Release: 2.1.0

Adding CTRL

.circleci/config.yml

@@ -81,7 +81,6 @@ jobs:
             - checkout
             - run: sudo pip install --progress-bar off -r docs/requirements.txt
             - run: sudo pip install --progress-bar off -r requirements.txt
-            - run: cd docs/source && ln -s ../../examples/README.md examples.md && cd -
             - run: cd docs && make clean && make html && scp -r -oStrictHostKeyChecking=no _build/html/* $doc:$dir
 workflow_filters: &workflow_filters
     filters:

.github/ISSUE_TEMPLATE/--new-model-addition.md

@@ -0,0 +1,23 @@
+---
+name: "\U0001F31FNew model addition"
+about: Submit a proposal/request to implement a new Transformer-based model
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+# 🌟New model addition
+
+## Model description
+
+<!-- Important information -->
+
+## Open Source status
+
+* [ ] the model implementation is available: (give details)
+* [ ] the model weights are available: (give details)
+
+## Additional context
+
+<!-- Add any other context about the problem here. -->

.github/ISSUE_TEMPLATE/bug-report.md

@@ -1,6 +1,10 @@
 ---
 name: "\U0001F41B Bug Report"
 about: Submit a bug report to help us improve PyTorch Transformers
+title: ''
+labels: ''
+assignees: ''
+
 ---
 
 ## 🐛 Bug
@@ -45,4 +49,4 @@ Steps to reproduce the behavior:
 
 ## Additional context
 
-<!-- Add any other context about the problem here. -->
+<!-- Add any other context about the problem here. -->

.github/ISSUE_TEMPLATE/feature-request.md

@@ -1,6 +1,10 @@
 ---
 name: "\U0001F680 Feature Request"
 about: Submit a proposal/request for a new PyTorch Transformers feature
+title: ''
+labels: ''
+assignees: ''
+
 ---
 
 ## 🚀 Feature
@@ -13,4 +17,4 @@ about: Submit a proposal/request for a new PyTorch Transformers feature
 
 ## Additional context
 
-<!-- Add any other context or screenshots about the feature request here. -->
+<!-- Add any other context or screenshots about the feature request here. -->

.github/ISSUE_TEMPLATE/migration.md

@@ -1,6 +1,10 @@
 ---
 name: "\U0001F4DA Migration from PyTorch-pretrained-Bert"
 about: Report a problem when migrating from PyTorch-pretrained-Bert to Transformers
+title: ''
+labels: ''
+assignees: ''
+
 ---
 
 ## 📚 Migration
@@ -40,4 +44,4 @@ Details of the issue:
 
 ## Additional context
 
-<!-- Add any other context about the problem here. -->
+<!-- Add any other context about the problem here. -->

.github/ISSUE_TEMPLATE/question-help.md

@@ -1,8 +1,12 @@
 ---
 name: "❓Questions & Help"
 about: Start a general discussion related to PyTorch Transformers
+title: ''
+labels: ''
+assignees: ''
+
 ---
 
 ## ❓ Questions & Help
 
-<!-- A clear and concise description of the question. -->
+<!-- A clear and concise description of the question. -->

.gitignore

@@ -118,6 +118,9 @@ dmypy.json
 # vscode
 .vscode
 
+# Pycharm
+.idea
+
 # TF code
 tensorflow_code
 
@@ -131,4 +134,7 @@ examples/runs
 
 # data
 /data
-serialization_dir
+serialization_dir
+
+# emacs
+*.*~

CONTRIBUTING.md

@@ -0,0 +1,175 @@
+# How to contribute to transformers?
+
+Everyone is welcome to contribute, and we value everybody's contribution. Code
+is thus not the only way to help the community. Answering questions, helping
+others, reaching out and improving the documentations are immensely valuable to
+the community.
+
+It also helps us if you spread the word: reference the library from blog posts
+on the awesome projects it made possible, shout out on Twitter every time it has
+helped you, or simply star the repo to say "thank you".
+
+## You can contribute in so many ways!
+
+There are 4 ways you can contribute to transformers:
+* Fixing outstanding issues with the existing code;
+* Implementing new models;
+* Contributing to the examples or to the documentation;
+* Submitting issues related to bugs or desired new features.
+
+*All are equally valuable to the community.*
+
+## Submitting a new issue or feature request
+
+Do your best to follow these guidelines when submitting an issue or a feature
+request. It will make it easier for us to come back to you quickly and with good
+feedback.
+
+### Did you find a bug?
+
+The transformers are robust and reliable thanks to the users who notify us of
+the problems they encounter. So thank you for reporting an issue.
+
+First, we would really appreciate it if you could **make sure the bug was not
+already reported** (use the search bar on Github under Issues).
+
+Did not find it? :( So we can act quickly on it, please follow these steps:
+
+* Include your **OS type and version**, the versions of **Python**, **PyTorch** and
+  **Tensorflow** when applicable;
+* A short, self-contained, code snippet that allows us to reproduce the bug in
+  less than 30s;
+* Provide the *full* traceback if an exception is raised.
+
+To get the OS and software versions, execute the following code and copy-paste
+the output:
+
+```
+import platform; print("Platform", platform.platform())
+import sys; print("Python", sys.version)
+import torch; print("PyTorch", torch.__version__)
+import tensorflow; print("Tensorflow", tensorflow.__version__)
+```
+
+### Do you want to implement a new model?
+
+Awesome! Please provide the following information:
+
+* Short description of the model and link to the paper;
+* Link to the implementation if it is open-source;
+* Link to the model weights if they are available.
+
+If you are willing to contribute the model yourself, let us know so we can best
+guide you.
+
+### Do you want a new feature (that is not a model)?
+
+A world-class feature request addresses the following points:
+
+1. Motivation first:
+  * Is it related to a problem/frustration with the library? If so, please explain
+    why. Providing a code snippet that demonstrates the problem is best.
+  * Is it related to something you would need for a project? We'd love to hear
+    about it!
+  * Is it something you worked on and think could benefit the community?
+    Awesome! Tell us what problem it solved for you.
+2. Write a *full paragraph* describing the feature;
+3. Provide a **code snippet** that demonstrates its future use;
+4. In case this is related to a paper, please attach a link;
+5. Attach any additional information (drawings, screenshots, etc.) you think may help.
+
+If your issue is well written we're already 80% of the way there by the time you
+post it.
+
+## Start contributing! (Pull Requests)
+
+Before writing code, we strongly advise you to search through the exising PRs or
+issues to make sure that nobody is already working on the same thing. If you are
+unsure, it is always a good idea to open an issue to get some feedback.
+
+You will need basic `git` proficiency to be able to contribute to
+`transformers`. `git` is not the easiest tool to use but it has the greatest
+manual. Type `git --help` in a shell and enjoy. If you prefer books, [Pro
+Git](https://git-scm.com/book/en/v2) is a very good reference.
+
+Follow these steps to start contributing:
+
+1. Fork the [repository](https://github.com/huggingface/transformers) by
+   clicking on the 'Fork' button on the repository's page. This creates a copy of the code
+   under your github user account.
+2. Clone your fork to your local disk, and add the base repository as a remote:
+   
+   ```bash
+   $ git clone git@github.com:<your Github handle>/transformers.git
+   $ cd transformers
+   $ git remote add upstream git@github.com:huggingface/transformers.git
+   ```
+
+3. Create a new branch to hold your development changes:
+
+   ```bash
+   $ git checkout -b a-descriptive-name-for-my-changes
+   ```
+   
+   **do not** work on the `master` branch.
+   
+4. Set up a development environment by running the following command in a virtual environment:
+
+   ```bash
+   $ pip install -r requirements-dev.txt
+   ```
+
+5. Develop the features on your branch. Add changed files using `git add` and
+   then `git commit` to record your changes locally:
+   
+   ```bash
+   $ git add modified_file.py
+   $ git commit
+   ```
+   
+   Please write [good commit
+   messages](https://chris.beams.io/posts/git-commit/). It
+   is a good idea to sync your copy of the code with the original repository
+   regularly. This way you can quickly account for changes:
+   
+   ```bash
+   $ git fetch upstream
+   $ git rebase upstream/master
+   ```
+   
+   Push the changes to your account using:
+   
+   ```bash
+   $ git push -u origin a-descriptive-name-for-my-changes
+   ```
+   
+6. Once you are satisfied (**and the checklist below is happy too**), go to the
+   webpage of your fork on Github. Click on 'Pull request' to send your changes
+   to the project maintainers for review.
+   
+7. It's ok if maintainers ask you for changes. It happens to core contributors
+   too! So everyone can see the changes in the Pull request, work in your local
+   branch and push the changes to your fork. They will automatically appear in
+   the pull request.
+
+
+### Checklist
+
+1. The title of your pull request should be a summary of its contribution;
+2. If your pull request adresses an issue, please mention the issue number in
+   the pull request description to make sure they are linked (and people
+   consulting the issue know you are working on it);
+3. To indicate a work in progress please prefix the title with `[WIP]`. These
+   are useful to avoid duplicated work, and to differentiate it from PRs ready
+   to be merged;
+4. Make sure pre-existing tests still pass;
+5. Add high-coverage tests. No quality test, no merge;
+6. All public methods must have informative doctrings;
+
+
+### Style guide
+
+For documentation strings, `transformers` follows the [google
+style](https://google.github.io/styleguide/pyguide.html).
+
+#### This guide was heavily inspired by the awesome [scikit-learn guide to contributing](https://github.com/scikit-learn/scikit-learn/blob/master/CONTRIBUTING.md)

README.md

@@ -4,7 +4,7 @@
     <br>
 <p>
 <p align="center">
-    <a href="https://github.com/huggingface/transformers/blob/master/LICENSE">
+    <a href="https://circleci.com/gh/huggingface/transformers">
         <img alt="Build" src="https://img.shields.io/circleci/build/github/huggingface/transformers/master">
     </a>
     <a href="https://github.com/huggingface/transformers/blob/master/LICENSE">
@@ -22,7 +22,7 @@
 <p>State-of-the-art Natural Language Processing for TensorFlow 2.0 and PyTorch
 </h3>
 
-🤗 Transformers (formerly known as `pytorch-transformers` and `pytorch-pretrained-bert`) provides state-of-the-art general-purpose architectures (BERT, GPT-2, RoBERTa, XLM, DistilBert, XLNet...) for Natural Language Understanding (NLU) and Natural Language Generation (NLG) with over 32+ pretrained models in 100+ languages and deep interoperability between TensorFlow 2.0 and PyTorch.
+🤗 Transformers (formerly known as `pytorch-transformers` and `pytorch-pretrained-bert`) provides state-of-the-art general-purpose architectures (BERT, GPT-2, RoBERTa, XLM, DistilBert, XLNet, CTRL...) for Natural Language Understanding (NLU) and Natural Language Generation (NLG) with over 32+ pretrained models in 100+ languages and deep interoperability between TensorFlow 2.0 and PyTorch.
 
 ### Features
 
@@ -54,19 +54,22 @@ Choose the right framework for every part of a model's lifetime
 | [Model architectures](#model-architectures) | Architectures (with pretrained weights) |
 | [Online demo](#online-demo) | Experimenting with this repo’s text generation capabilities |
 | [Quick tour: Usage](#quick-tour) | Tokenizers & models usage: Bert and GPT-2 |
-| [Quick tour: TF 2.0 and PyTorch ](#Quick-tour-TF-2.0-training-and-PyTorch-interoperability) | Train a TF 2.0 model in 10 lines of code, load it in PyTorch |
+| [Quick tour: TF 2.0 and PyTorch ](#Quick-tour-TF-20-training-and-PyTorch-interoperability) | Train a TF 2.0 model in 10 lines of code, load it in PyTorch |
 | [Quick tour: Fine-tuning/usage scripts](#quick-tour-of-the-fine-tuningusage-scripts) | Using provided scripts: GLUE, SQuAD and Text generation |
-| [Migrating from pytorch-transformers to transformers](#Migrating-from-pytorch-transformers-to-transformers) | Migrating your code from pytorch-pretrained-bert to transformers |
+| [Migrating from pytorch-transformers to transformers](#Migrating-from-pytorch-transformers-to-transformers) | Migrating your code from pytorch-transformers to transformers |
 | [Migrating from pytorch-pretrained-bert to pytorch-transformers](#Migrating-from-pytorch-pretrained-bert-to-transformers) | Migrating your code from pytorch-pretrained-bert to transformers |
 | [Documentation](https://huggingface.co/transformers/) | Full API documentation and more |
 
 ## Installation
 
-This repo is tested on Python 2.7 and 3.5+ (examples are tested only on python 3.5+) and PyTorch 1.0.0+
+This repo is tested on Python 2.7 and 3.5+ (examples are tested only on python 3.5+), PyTorch 1.0.0+ and TensorFlow 2.0.0-rc1
 
 ### With pip
 
-Transformers can be installed by pip as follows:
+First you need to install one of, or both, TensorFlow 2.0 and PyTorch.
+Please refer to [TensorFlow installation page](https://www.tensorflow.org/install/pip#tensorflow-2.0-rc-is-available) and/or [PyTorch installation page](https://pytorch.org/get-started/locally/#start-locally) regarding the specific install command for your platform.
+
+When TensorFlow 2.0 and/or PyTorch has been installed, 🤗 Transformers can be installed using pip as follows:
 
 ```bash
 pip install transformers
@@ -74,7 +77,10 @@ pip install transformers
 
 ### From source
 
-Clone the repository and run:
+Here also, you first need to install one of, or both, TensorFlow 2.0 and PyTorch.
+Please refer to [TensorFlow installation page](https://www.tensorflow.org/install/pip#tensorflow-2.0-rc-is-available) and/or [PyTorch installation page](https://pytorch.org/get-started/locally/#start-locally) regarding the specific install command for your platform.
+
+When TensorFlow 2.0 and/or PyTorch has been installed, you can install from source by cloning the repository and running:
 
 ```bash
 pip install [--editable] .
@@ -82,10 +88,12 @@ pip install [--editable] .
 
 ### Tests
 
-A series of tests is included for the library and the example scripts. Library tests can be found in the [tests folder](https://github.com/huggingface/transformers/tree/master/transformers/tests) and examples tests in the [examples folder](https://github.com/huggingface/transformers/tree/master/examples).
+A series of tests are included for the library and the example scripts. Library tests can be found in the [tests folder](https://github.com/huggingface/transformers/tree/master/transformers/tests) and examples tests in the [examples folder](https://github.com/huggingface/transformers/tree/master/examples).
 
 These tests can be run using `pytest` (install pytest if needed with `pip install pytest`).
 
+Depending on which framework is installed (TensorFlow 2.0 and/or PyTorch), the irrelevant tests will be skipped. Ensure that both frameworks are installed if you want to execute all tests.
+
 You can run the tests from the root of the cloned repository with the commands:
 
 ```bash
@@ -97,10 +105,9 @@ python -m pytest -sv ./examples/
 
 You should check out our [`swift-coreml-transformers`](https://github.com/huggingface/swift-coreml-transformers) repo.
 
-It contains an example of a conversion script from a Pytorch trained Transformer model (here, `GPT-2`) to a CoreML model that runs on iOS devices.
+It contains a set of tools to convert PyTorch or TensorFlow 2.0 trained Transformer models (currently contains `GPT-2`, `DistilGPT-2`, `BERT`, and `DistilBERT`) to CoreML models that run on iOS devices.
 
-At some point in the future, you'll be able to seamlessly move from pre-training or fine-tuning models in PyTorch to productizing them in CoreML,
-or prototype a model or an app in CoreML then research its hyperparameters or architecture from PyTorch. Super exciting!
+At some point in the future, you'll be able to seamlessly move from pre-training or fine-tuning models to productizing them in CoreML, or prototype a model or an app in CoreML then research its hyperparameters or architecture from TensorFlow 2.0 and/or PyTorch. Super exciting!
 
 ## Model architectures
 
@@ -113,8 +120,8 @@ or prototype a model or an app in CoreML then research its hyperparameters or ar
 5. **[XLNet](https://github.com/zihangdai/xlnet/)** (from Google/CMU) released with the paper [​XLNet: Generalized Autoregressive Pretraining for Language Understanding](https://arxiv.org/abs/1906.08237) by Zhilin Yang*, Zihang Dai*, Yiming Yang, Jaime Carbonell, Ruslan Salakhutdinov, Quoc V. Le.
 6. **[XLM](https://github.com/facebookresearch/XLM/)** (from Facebook) released together with the paper [Cross-lingual Language Model Pretraining](https://arxiv.org/abs/1901.07291) by Guillaume Lample and Alexis Conneau.
 7. **[RoBERTa](https://github.com/pytorch/fairseq/tree/master/examples/roberta)** (from Facebook), released together with the paper a [Robustly Optimized BERT Pretraining Approach](https://arxiv.org/abs/1907.11692) by Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, Veselin Stoyanov.
-8. **[DistilBERT](https://github.com/huggingface/transformers/tree/master/examples/distillation)** (from HuggingFace), released together with the blogpost [Smaller, faster, cheaper, lighter: Introducing DistilBERT, a distilled version of BERT](https://medium.com/huggingface/distilbert-8cf3380435b5
-) by Victor Sanh, Lysandre Debut and Thomas Wolf.
+8. **[DistilBERT](https://github.com/huggingface/transformers/tree/master/examples/distillation)** (from HuggingFace), released together with the paper [DistilBERT, a distilled version of BERT: smaller, faster, cheaper and lighter](https://arxiv.org/abs/1910.01108) by Victor Sanh, Lysandre Debut and Thomas Wolf. The same method has been applied to compress GPT2 into [DistilGPT2](https://github.com/huggingface/transformers/tree/master/examples/distillation).
+9. **[CTRL](https://github.com/salesforce/ctrl/)** (from Salesforce) released with the paper [CTRL: A Conditional Transformer Language Model for Controllable Generation](https://arxiv.org/abs/1909.05858) by Nitish Shirish Keskar*, Bryan McCann*, Lav R. Varshney, Caiming Xiong and Richard Socher.
 
 These implementations have been tested on several datasets (see the example scripts) and should match the performances of the original implementations (e.g. ~93 F1 on SQuAD for BERT Whole-Word-Masking, ~88 F1 on RocStories for OpenAI GPT, ~18.3 perplexity on WikiText 103 for Transformer-XL, ~0.916 Peason R coefficient on STS-B for XLNet). You can find more details on the performances in the Examples section of the [documentation](https://huggingface.co/transformers/examples.html).
 
@@ -141,6 +148,7 @@ from transformers import *
 MODELS = [(BertModel,       BertTokenizer,       'bert-base-uncased'),
           (OpenAIGPTModel,  OpenAIGPTTokenizer,  'openai-gpt'),
           (GPT2Model,       GPT2Tokenizer,       'gpt2'),
+          (CTRLModel,       CTRLTokenizer,       'ctrl'),
           (TransfoXLModel,  TransfoXLTokenizer,  'transfo-xl-wt103'),
           (XLNetModel,      XLNetTokenizer,      'xlnet-base-cased'),
           (XLMModel,        XLMTokenizer,        'xlm-mlm-enfr-1024'),
@@ -173,24 +181,24 @@ for model_class in BERT_MODEL_CLASSES:
     # Load pretrained model/tokenizer
     model = model_class.from_pretrained('bert-base-uncased')
 
-# Models can return full list of hidden-states & attentions weights at each layer
-model = model_class.from_pretrained(pretrained_weights,
-                                    output_hidden_states=True,
-                                    output_attentions=True)
-input_ids = torch.tensor([tokenizer.encode("Let's see all hidden-states and attentions on this text")])
-all_hidden_states, all_attentions = model(input_ids)[-2:]
+    # Models can return full list of hidden-states & attentions weights at each layer
+    model = model_class.from_pretrained(pretrained_weights,
+                                        output_hidden_states=True,
+                                        output_attentions=True)
+    input_ids = torch.tensor([tokenizer.encode("Let's see all hidden-states and attentions on this text")])
+    all_hidden_states, all_attentions = model(input_ids)[-2:]
 
-# Models are compatible with Torchscript
-model = model_class.from_pretrained(pretrained_weights, torchscript=True)
-traced_model = torch.jit.trace(model, (input_ids,))
+    # Models are compatible with Torchscript
+    model = model_class.from_pretrained(pretrained_weights, torchscript=True)
+    traced_model = torch.jit.trace(model, (input_ids,))
 
-# Simple serialization for models and tokenizers
-model.save_pretrained('./directory/to/save/')  # save
-model = model_class.from_pretrained('./directory/to/save/')  # re-load
-tokenizer.save_pretrained('./directory/to/save/')  # save
-tokenizer = tokenizer_class.from_pretrained('./directory/to/save/')  # re-load
+    # Simple serialization for models and tokenizers
+    model.save_pretrained('./directory/to/save/')  # save
+    model = model_class.from_pretrained('./directory/to/save/')  # re-load
+    tokenizer.save_pretrained('./directory/to/save/')  # save
+    tokenizer = BertTokenizer.from_pretrained('./directory/to/save/')  # re-load
 
-# SOTA examples for GLUE, SQUAD, text generation...
+    # SOTA examples for GLUE, SQUAD, text generation...
 ```
 
 ## Quick tour TF 2.0 training and PyTorch interoperability
@@ -200,7 +208,7 @@ Let's do a quick example of how a TensorFlow 2.0 model can be trained in 12 line
 ```python
 import tensorflow as tf
 import tensorflow_datasets
-from pytorch_transformers import *
+from transformers import *
 
 # Load dataset, tokenizer, model from pretrained model/vocabulary
 tokenizer = BertTokenizer.from_pretrained('bert-base-cased')
@@ -208,8 +216,8 @@ model = TFBertForSequenceClassification.from_pretrained('bert-base-cased')
 data = tensorflow_datasets.load('glue/mrpc')
 
 # Prepare dataset for GLUE as a tf.data.Dataset instance
-train_dataset = glue_convert_examples_to_features(data['train'], tokenizer, 128, 'mrpc')
-valid_dataset = glue_convert_examples_to_features(data['validation'], tokenizer, 128, 'mrpc')
+train_dataset = glue_convert_examples_to_features(data['train'], tokenizer, max_length=128, task='mrpc')
+valid_dataset = glue_convert_examples_to_features(data['validation'], tokenizer, max_length=128, task='mrpc')
 train_dataset = train_dataset.shuffle(100).batch(32).repeat(2)
 valid_dataset = valid_dataset.batch(64)
 
@@ -246,7 +254,7 @@ The library comprises several example scripts with SOTA performances for NLU and
 
 - `run_glue.py`: an example fine-tuning Bert, XLNet and XLM on nine different GLUE tasks (*sequence-level classification*)
 - `run_squad.py`: an example fine-tuning Bert, XLNet and XLM on the question answering dataset SQuAD 2.0 (*token-level classification*)
-- `run_generation.py`: an example using GPT, GPT-2, Transformer-XL and XLNet for conditional language generation
+- `run_generation.py`: an example using GPT, GPT-2, CTRL, Transformer-XL and XLNet for conditional language generation
 - other model-specific examples (see the documentation).
 
 Here are three quick usage examples for these scripts:
@@ -384,10 +392,10 @@ python $SQUAD_DIR/evaluate-v1.1.py $SQUAD_DIR/dev-v1.1.json ../models/wwm_uncase
 
 This is the model provided as `bert-large-uncased-whole-word-masking-finetuned-squad`.
 
-### `run_generation.py`: Text generation with GPT, GPT-2, Transformer-XL and XLNet
+### `run_generation.py`: Text generation with GPT, GPT-2, CTRL, Transformer-XL and XLNet
 
 A conditional generation script is also included to generate text from a prompt.
-The generation script includes the [tricks](https://github.com/rusiaaman/XLNet-gen#methodology) proposed by Aman Rusia to get high quality generation with memory models like Transformer-XL and XLNet (include a predefined text to make short inputs longer).
+The generation script includes the [tricks](https://github.com/rusiaaman/XLNet-gen#methodology) proposed by Aman Rusia to get high-quality generation with memory models like Transformer-XL and XLNet (include a predefined text to make short inputs longer).
 
 Here is how to run the script with the small version of OpenAI GPT-2 model:
 
@@ -398,6 +406,16 @@ python ./examples/run_generation.py \
     --model_name_or_path=gpt2 \
 ```
 
+and from the Salesforce CTRL model: 
+```shell
+python ./examples/run_generation.py \
+    --model_type=ctrl \
+    --length=20 \
+    --model_name_or_path=gpt2 \
+    --temperature=0 \
+    --repetition_penalty=1.2 \
+```
+
 ## Migrating from pytorch-transformers to transformers
 
 Here is a quick summary of what you should take care of when migrating from `pytorch-transformers` to `transformers`.
@@ -417,9 +435,9 @@ Here is a quick summary of what you should take care of when migrating from `pyt
 
 ### Models always output `tuples`
 
-The main breaking change when migrating from `pytorch-pretrained-bert` to `transformers` is that the models forward method always outputs a `tuple` with various elements depending on the model and the configuration parameters.
+The main breaking change when migrating from `pytorch-pretrained-bert` to `transformers` is that every model's forward method always outputs a `tuple` with various elements depending on the model and the configuration parameters.
 
-The exact content of the tuples for each model are detailed in the models' docstrings and the [documentation](https://huggingface.co/transformers/).
+The exact content of the tuples for each model is detailed in the models' docstrings and the [documentation](https://huggingface.co/transformers/).
 
 In pretty much every case, you will be fine by taking the first element of the output as the output you previously used in `pytorch-pretrained-bert`.
 
@@ -445,13 +463,17 @@ outputs = model(input_ids, labels=labels)
 loss, logits, attentions = outputs
 ```
 
+### Using hidden states
+
+By enabling the configuration option `output_hidden_states`, it was possible to retrieve the last hidden states of the encoder. In `pytorch-transformers` as well as `transformers` the return value has changed slightly: `all_hidden_states` now also includes the hidden state of the embeddings in addition to those of the encoding layers. This allows users to easily access the embeddings final state.
+
 ### Serialization
 
-Breaking change in the `from_pretrained()`method:
+Breaking change in the `from_pretrained()` method:
 
-1. Models are now set in evaluation mode by default when instantiated with the `from_pretrained()` method. To train them don't forget to set them back in training mode (`model.train()`) to activate the dropout modules.
+1. Models are now set in evaluation mode by default when instantiated with the `from_pretrained()` method. To train them, don't forget to set them back in training mode (`model.train()`) to activate the dropout modules.
 
-2. The additional `*input` and `**kwargs` arguments supplied to the `from_pretrained()` method used to be directly passed to the underlying model's class `__init__()` method. They are now used to update the model configuration attribute instead which can break derived model classes build based on the previous `BertForSequenceClassification` examples. We are working on a way to mitigate this breaking change in [#866](https://github.com/huggingface/transformers/pull/866) by forwarding the the model `__init__()` method (i) the provided positional arguments and (ii) the keyword arguments which do not match any configuration class attributes.
+2. The additional `*input` and `**kwargs` arguments supplied to the `from_pretrained()` method used to be directly passed to the underlying model's class `__init__()` method. They are now used to update the model configuration attribute instead, which can break derived model classes built based on the previous `BertForSequenceClassification` examples. We are working on a way to mitigate this breaking change in [#866](https://github.com/huggingface/transformers/pull/866) by forwarding the the model's `__init__()` method (i) the provided positional arguments and (ii) the keyword arguments which do not match any configuration class attributes.
 
 Also, while not a breaking change, the serialization methods have been standardized and you probably should switch to the new method `save_pretrained(save_directory)` if you were using any other serialization method before.
 
@@ -523,4 +545,4 @@ for batch in train_data:
 
 ## Citation
 
-At the moment, there is no paper associated to Transformers but we are working on preparing one. In the meantime, please include a mention of the library and a link to the present repository if you use this work in a published or open-source project.
+At the moment, there is no paper associated with Transformers but we are working on preparing one. In the meantime, please include a mention of the library and a link to the present repository if you use this work in a published or open-source project.

docs/README.md

@@ -34,11 +34,11 @@ pip install recommonmark
 
 ## Building the documentation
 
-Make sure that there is a symlink from the `example` file (in /examples) inside the source folder. Run the followig 
+Make sure that there is a symlink from the `example` file (in /examples) inside the source folder. Run the following 
 command to generate it:
 
 ```bash
-ln -s ../../examples/README.md source/examples.md
+ln -s ../../examples/README.md examples.md
 ```
 
 Once you have setup `sphinx`, you can build the documentation by running the following command in the `/docs` folder:
@@ -50,7 +50,7 @@ make html
 ---
 **NOTE**
 
-If you are adding/removing elements from the toc-tree or from any strutural item, it is recommended to clean the build
+If you are adding/removing elements from the toc-tree or from any structural item, it is recommended to clean the build
 directory before rebuilding. Run the following command to clean and build:
 
 ```bash

docs/requirements.txt

@@ -26,4 +26,7 @@ sphinxcontrib-jsmath==1.0.1
 sphinxcontrib-qthelp==1.0.2
 sphinxcontrib-serializinghtml==1.1.3
 urllib3==1.25.3
-sphinx-markdown-tables==0.0.9
+sphinx-markdown-tables==0.0.9
+numpy==1.17.2
+tensorflow==2.0.0rc2
+torch==1.2.0

docs/source/_static/css/huggingface.css

@@ -1,5 +1,3 @@
-huggingface.css
-
 /* The literal code blocks */
 .rst-content tt.literal, .rst-content tt.literal, .rst-content code.literal {
     color: #6670FF;
@@ -44,11 +42,11 @@ huggingface.css
 /* The text items on the toc tree */
 .wy-menu-vertical a {
     color: #FFFFDD;
-    font-family: Calibre-Light;
+    font-family: Calibre-Light, sans-serif;
 }
 .wy-menu-vertical header, .wy-menu-vertical p.caption{
     color: white;
-    font-family: Calibre-Light;
+    font-family: Calibre-Light, sans-serif;
 }
 
 /* The color inside the selected toc tree block */
@@ -85,7 +83,7 @@ a {
     border-right: solid 2px #FB8D68;
     border-left: solid 2px #FB8D68;
     color: #FB8D68;
-    font-family: Calibre-Light;
+    font-family: Calibre-Light, sans-serif;
     border-top: none;
     font-style: normal !important;
 }
@@ -136,14 +134,14 @@ a {
 
 /* class and method names in doc */
 .rst-content dl:not(.docutils) tt.descname, .rst-content dl:not(.docutils) tt.descclassname, .rst-content dl:not(.docutils) tt.descname, .rst-content dl:not(.docutils) code.descname, .rst-content dl:not(.docutils) tt.descclassname, .rst-content dl:not(.docutils) code.descclassname{
-    font-family: Calibre;
+    font-family: Calibre, sans-serif;
     font-size: 20px !important;
 }
 
 /* class name in doc*/
 .rst-content dl:not(.docutils) tt.descname, .rst-content dl:not(.docutils) tt.descname, .rst-content dl:not(.docutils) code.descname{
     margin-right: 10px;
-    font-family: Calibre-Medium;
+    font-family: Calibre-Medium, sans-serif;
 }
 
 /* Method and class parameters */
@@ -160,17 +158,17 @@ a {
 
 /* FONTS */
 body{
-    font-family: Calibre;
+    font-family: Calibre, sans-serif;
     font-size: 16px;
 }
 
 h1 {
-    font-family: Calibre-Thin;
+    font-family: Calibre-Thin, sans-serif;
     font-size: 70px;
 }
 
 h2, .rst-content .toctree-wrapper p.caption, h3, h4, h5, h6, legend{
-    font-family: Calibre-Medium;
+    font-family: Calibre-Medium, sans-serif;
 }
 
 @font-face {
@@ -196,4 +194,3 @@ h2, .rst-content .toctree-wrapper p.caption, h3, h4, h5, h6, legend{
     src: url(./Calibre-Thin.otf);
     font-weight:400;
 }
-

docs/source/conf.py

@@ -26,7 +26,7 @@ author = u'huggingface'
 # The short X.Y version
 version = u''
 # The full version, including alpha/beta/rc tags
-release = u'1.2.0'
+release = u'2.1.0'
 
 
 # -- General configuration ---------------------------------------------------

docs/source/examples.md

@@ -0,0 +1 @@
+../../examples/README.md

docs/source/index.rst

@@ -5,6 +5,8 @@ Transformers
 (BERT, GPT-2, RoBERTa, XLM, DistilBert, XLNet...) for Natural Language Understanding (NLU) and Natural Language Generation
 (NLG) with over 32+ pretrained models in 100+ languages and deep interoperability between TensorFlow 2.0 and PyTorch.
 
+This is the documentation of our repository `transformers <https://github.com/huggingface/transformers>`__.
+
 Features
 ---------------------------------------------------
 
@@ -13,17 +15,20 @@ Features
 - High performance on NLU and NLG tasks
 - Low barrier to entry for educators and practitioners
 
-State-of-the-art NLP for everyone
+State-of-the-art NLP for everyone:
+
 - Deep learning researchers
 - Hands-on practitioners
 - AI/ML/NLP teachers and educators
 
-Lower compute costs, smaller carbon footprint
+Lower compute costs, smaller carbon footprint:
+
 - Researchers can share trained models instead of always retraining
 - Practitioners can reduce compute time and production costs
 - 8 architectures with over 30 pretrained models, some in more than 100 languages
 
-Choose the right framework for every part of a model's lifetime
+Choose the right framework for every part of a model's lifetime:
+
 - Train state-of-the-art models in 3 lines of code
 - Deep interoperability between TensorFlow 2.0 and PyTorch models
 - Move a single model between TF2.0/PyTorch frameworks at will
@@ -41,8 +46,7 @@ The library currently contains PyTorch and Tensorflow implementations, pre-train
 5. `XLNet <https://github.com/zihangdai/xlnet>`_ (from Google/CMU) released with the paper `​XLNet: Generalized Autoregressive Pretraining for Language Understanding <https://arxiv.org/abs/1906.08237>`_ by Zhilin Yang*, Zihang Dai*, Yiming Yang, Jaime Carbonell, Ruslan Salakhutdinov, Quoc V. Le.
 6. `XLM <https://github.com/facebookresearch/XLM>`_ (from Facebook) released together with the paper `Cross-lingual Language Model Pretraining <https://arxiv.org/abs/1901.07291>`_ by Guillaume Lample and Alexis Conneau.
 7. `RoBERTa <https://github.com/pytorch/fairseq/tree/master/examples/roberta>`_ (from Facebook), released together with the paper a `Robustly Optimized BERT Pretraining Approach <https://arxiv.org/abs/1907.11692>`_ by Yinhan Liu, Myle Ott, Naman Goyal, Jingfei Du, Mandar Joshi, Danqi Chen, Omer Levy, Mike Lewis, Luke Zettlemoyer, Veselin Stoyanov.
-8. `DistilBERT <https://huggingface.co/transformers/model_doc/distilbert.html>`_ (from HuggingFace) released together with the blog post `Smaller, faster, cheaper, lighter: Introducing DistilBERT, a distilled version of BERT <https://medium.com/huggingface/distilbert-8cf3380435b5>`_ by Victor Sanh, Lysandre Debut and Thomas Wolf.
-
+8. `DistilBERT <https://huggingface.co/transformers/model_doc/distilbert.html>`_ (from HuggingFace) released together with the paper `DistilBERT, a distilled version of BERT: smaller, faster, cheaper and lighter <https://arxiv.org/abs/1910.01108>`_ by Victor Sanh, Lysandre Debut and Thomas Wolf. The same method has been applied to compress GPT2 into `DistilGPT2 <https://github.com/huggingface/transformers/tree/master/examples/distillation>`_.
 
 .. toctree::
     :maxdepth: 2
@@ -58,6 +62,7 @@ The library currently contains PyTorch and Tensorflow implementations, pre-train
     migration
     bertology
     torchscript
+    multilingual
 
 .. toctree::
     :maxdepth: 2
@@ -82,3 +87,4 @@ The library currently contains PyTorch and Tensorflow implementations, pre-train
     model_doc/xlnet
     model_doc/roberta
     model_doc/distilbert
+    model_doc/ctrl

docs/source/installation.md

@@ -0,0 +1,58 @@
+# Installation
+
+Transformers is tested on Python 2.7 and 3.5+ (examples are tested only on python 3.5+) and PyTorch 1.1.0
+
+## With pip
+
+PyTorch Transformers can be installed using pip as follows:
+
+``` bash
+pip install transformers
+```
+
+## From source
+
+To install from source, clone the repository and install with:
+
+``` bash
+git clone https://github.com/huggingface/transformers.git
+cd transformers
+pip install [--editable] .
+```
+
+## Tests
+
+An extensive test suite is included to test the library behavior and several examples. Library tests can be found in the [tests folder](https://github.com/huggingface/transformers/tree/master/transformers/tests) and examples tests in the [examples folder](https://github.com/huggingface/transformers/tree/master/examples).
+
+Tests can be run using `pytest` (install pytest if needed with `pip install pytest`).
+
+Run all the tests from the root of the cloned repository with the commands:
+
+``` bash
+python -m pytest -sv ./transformers/tests/
+python -m pytest -sv ./examples/
+```
+
+## OpenAI GPT original tokenization workflow
+
+If you want to reproduce the original tokenization process of the `OpenAI GPT` paper, you will need to install `ftfy` (use version 4.4.3 if you are using Python 2) and `SpaCy`:
+
+``` bash
+pip install spacy ftfy==4.4.3
+python -m spacy download en
+```
+
+If you don't install `ftfy` and `SpaCy`, the `OpenAI GPT` tokenizer will default to tokenize using BERT's `BasicTokenizer` followed by Byte-Pair Encoding (which should be fine for most usage, don't worry).
+
+## Note on model downloads (Continuous Integration or large-scale deployments)
+
+If you expect to be downloading large volumes of models (more than 1,000) from our hosted bucket (for instance through your CI setup, or a large-scale production deployment), please cache the model files on your end. It will be way faster, and cheaper. Feel free to contact us privately if you need any help.
+
+## Do you want to run a Transformer model on a mobile device?
+
+You should check out our [swift-coreml-transformers](https://github.com/huggingface/swift-coreml-transformers) repo.
+
+It contains a set of tools to convert PyTorch or TensorFlow 2.0 trained Transformer models (currently contains `GPT-2`, `DistilGPT-2`, `BERT`, and `DistilBERT`) to CoreML models that run on iOS devices.
+
+At some point in the future, you'll be able to seamlessly move from pre-training or fine-tuning models in PyTorch to productizing them in CoreML,
+or prototype a model or an app in CoreML then research its hyperparameters or architecture from PyTorch. Super exciting!

docs/source/installation.rst

@@ -1,71 +0,0 @@
-Installation
-================================================
-
-Transformers is tested on Python 2.7 and 3.5+ (examples are tested only on python 3.5+) and PyTorch 1.1.0
-
-With pip
-^^^^^^^^
-
-PyTorch Transformers can be installed using pip as follows:
-
-.. code-block:: bash
-
-   pip install transformers
-
-From source
-^^^^^^^^^^^
-
-To install from source, clone the repository and install with:
-
-.. code-block:: bash
-
-    git clone https://github.com/huggingface/transformers.git
-    cd transformers
-    pip install [--editable] .
-
-
-Tests
-^^^^^
-
-An extensive test suite is included to test the library behavior and several examples. Library tests can be found in the `tests folder <https://github.com/huggingface/transformers/tree/master/transformers/tests>`_ and examples tests in the `examples folder <https://github.com/huggingface/transformers/tree/master/examples>`_.
-
-Tests can be run using `pytest` (install pytest if needed with `pip install pytest`).
-
-Run all the tests from the root of the cloned repository with the commands:
-
-.. code-block:: bash
-
-    python -m pytest -sv ./transformers/tests/
-    python -m pytest -sv ./examples/
-
-
-OpenAI GPT original tokenization workflow
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-If you want to reproduce the original tokenization process of the ``OpenAI GPT`` paper, you will need to install ``ftfy`` (use version 4.4.3 if you are using Python 2) and ``SpaCy`` :
-
-.. code-block:: bash
-
-   pip install spacy ftfy==4.4.3
-   python -m spacy download en
-
-If you don't install ``ftfy`` and ``SpaCy``\ , the ``OpenAI GPT`` tokenizer will default to tokenize using BERT's ``BasicTokenizer`` followed by Byte-Pair Encoding (which should be fine for most usage, don't worry).
-
-
-Note on model downloads (Continuous Integration or large-scale deployments)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-If you expect to be downloading large volumes of models (more than 1,000) from our hosted bucket (for instance through your CI setup, or a large-scale production deployment), please cache the model files on your end. It will be way faster, and cheaper. Feel free to contact us privately if you need any help.
-
-
-Do you want to run a Transformer model on a mobile device?
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-You should check out our `swift-coreml-transformers <https://github.com/huggingface/swift-coreml-transformers>`_ repo.
-
-It contains an example of a conversion script from a Pytorch trained Transformer model (here, ``GPT-2``) to a CoreML model that runs on iOS devices.
-
-It also contains an implementation of BERT for Question answering.
-
-At some point in the future, you'll be able to seamlessly move from pre-training or fine-tuning models in PyTorch to productizing them in CoreML,
-or prototype a model or an app in CoreML then research its hyperparameters or architecture from PyTorch. Super exciting!

docs/source/main_classes/model.rst

@@ -17,5 +17,5 @@ The base class ``PreTrainedModel`` implements the common methods for loading/sav
 ``TFPreTrainedModel``
 ~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFPreTrainedModel
+.. autoclass:: transformers.TFPreTrainedModel
     :members:

docs/source/main_classes/processors.rst

@@ -8,20 +8,20 @@ Processors
 ~~~~~~~~~~~~~~~~~~~~~
 
 All processors follow the same architecture which is that of the
-:class:`~pytorch_transformers.data.processors.utils.DataProcessor`. The processor returns a list
-of :class:`~pytorch_transformers.data.processors.utils.InputExample`. These
-:class:`~pytorch_transformers.data.processors.utils.InputExample` can be converted to
-:class:`~pytorch_transformers.data.processors.utils.InputFeatures` in order to be fed to the model.
+:class:`~transformers.data.processors.utils.DataProcessor`. The processor returns a list
+of :class:`~transformers.data.processors.utils.InputExample`. These
+:class:`~transformers.data.processors.utils.InputExample` can be converted to
+:class:`~transformers.data.processors.utils.InputFeatures` in order to be fed to the model.
 
-.. autoclass:: pytorch_transformers.data.processors.utils.DataProcessor
+.. autoclass:: transformers.data.processors.utils.DataProcessor
     :members:
 
 
-.. autoclass:: pytorch_transformers.data.processors.utils.InputExample
+.. autoclass:: transformers.data.processors.utils.InputExample
     :members:
 
 
-.. autoclass:: pytorch_transformers.data.processors.utils.InputFeatures
+.. autoclass:: transformers.data.processors.utils.InputFeatures
     :members:
 
 
@@ -36,20 +36,20 @@ This library hosts a total of 10 processors for the following tasks: MRPC, MNLI,
 CoLA, SST2, STSB, QQP, QNLI, RTE and WNLI.
 
 Those processors are:
-    - :class:`~pytorch_transformers.data.processors.utils.MrpcProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.MnliProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.MnliMismatchedProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.Sst2Processor`
-    - :class:`~pytorch_transformers.data.processors.utils.StsbProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.QqpProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.QnliProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.RteProcessor`
-    - :class:`~pytorch_transformers.data.processors.utils.WnliProcessor`
+    - :class:`~transformers.data.processors.utils.MrpcProcessor`
+    - :class:`~transformers.data.processors.utils.MnliProcessor`
+    - :class:`~transformers.data.processors.utils.MnliMismatchedProcessor`
+    - :class:`~transformers.data.processors.utils.Sst2Processor`
+    - :class:`~transformers.data.processors.utils.StsbProcessor`
+    - :class:`~transformers.data.processors.utils.QqpProcessor`
+    - :class:`~transformers.data.processors.utils.QnliProcessor`
+    - :class:`~transformers.data.processors.utils.RteProcessor`
+    - :class:`~transformers.data.processors.utils.WnliProcessor`
 
 Additionally, the following method  can be used to load values from a data file and convert them to a list of
-:class:`~pytorch_transformers.data.processors.utils.InputExample`.
+:class:`~transformers.data.processors.utils.InputExample`.
 
-.. automethod:: pytorch_transformers.data.processors.glue.glue_convert_examples_to_features
+.. automethod:: transformers.data.processors.glue.glue_convert_examples_to_features
 
 Example usage
 ^^^^^^^^^^^^^^^^^^^^^^^^^

docs/source/model_doc/bert.rst

@@ -74,55 +74,55 @@ BERT
 ``TFBertModel``
 ~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertModel
+.. autoclass:: transformers.TFBertModel
     :members:
 
 
 ``TFBertForPreTraining``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForPreTraining
+.. autoclass:: transformers.TFBertForPreTraining
     :members:
 
 
 ``TFBertForMaskedLM``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForMaskedLM
+.. autoclass:: transformers.TFBertForMaskedLM
     :members:
 
 
 ``TFBertForNextSentencePrediction``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForNextSentencePrediction
+.. autoclass:: transformers.TFBertForNextSentencePrediction
     :members:
 
 
 ``TFBertForSequenceClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForSequenceClassification
+.. autoclass:: transformers.TFBertForSequenceClassification
     :members:
 
 
 ``TFBertForMultipleChoice``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForMultipleChoice
+.. autoclass:: transformers.TFBertForMultipleChoice
     :members:
 
 
 ``TFBertForTokenClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForTokenClassification
+.. autoclass:: transformers.TFBertForTokenClassification
     :members:
 
 
 ``TFBertForQuestionAnswering``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFBertForQuestionAnswering
+.. autoclass:: transformers.TFBertForQuestionAnswering
     :members:
 

docs/source/model_doc/ctrl.rst

@@ -0,0 +1,44 @@
+CTRL
+----------------------------------------------------
+
+``CTRLConfig``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.CTRLConfig
+    :members:
+
+
+``CTRLTokenizer``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.CTRLTokenizer
+    :members:
+
+
+``CTRLModel``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.CTRLModel
+    :members:
+
+
+``CTRLLMHeadModel``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.CTRLLMHeadModel
+    :members:
+
+
+``TFCTRLModel``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFCTRLModel
+    :members:
+
+
+``TFCTRLLMHeadModel``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autoclass:: transformers.TFCTRLLMHeadModel
+    :members:
+

docs/source/model_doc/distilbert.rst

@@ -45,26 +45,26 @@ DistilBERT
 ``TFDistilBertModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFDistilBertModel
+.. autoclass:: transformers.TFDistilBertModel
     :members:
 
 
 ``TFDistilBertForMaskedLM``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFDistilBertForMaskedLM
+.. autoclass:: transformers.TFDistilBertForMaskedLM
     :members:
 
 
 ``TFDistilBertForSequenceClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFDistilBertForSequenceClassification
+.. autoclass:: transformers.TFDistilBertForSequenceClassification
     :members:
 
 
 ``TFDistilBertForQuestionAnswering``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFDistilBertForQuestionAnswering
+.. autoclass:: transformers.TFDistilBertForQuestionAnswering
     :members:

docs/source/model_doc/gpt.rst

@@ -39,19 +39,19 @@ OpenAI GPT
 ``TFOpenAIGPTModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFOpenAIGPTModel
+.. autoclass:: transformers.TFOpenAIGPTModel
     :members:
 
 
 ``TFOpenAIGPTLMHeadModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFOpenAIGPTLMHeadModel
+.. autoclass:: transformers.TFOpenAIGPTLMHeadModel
     :members:
 
 
 ``TFOpenAIGPTDoubleHeadsModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFOpenAIGPTDoubleHeadsModel
+.. autoclass:: transformers.TFOpenAIGPTDoubleHeadsModel
     :members:

docs/source/model_doc/gpt2.rst

@@ -39,19 +39,19 @@ OpenAI GPT2
 ``TFGPT2Model``
 ~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFGPT2Model
+.. autoclass:: transformers.TFGPT2Model
     :members:
 
 
 ``TFGPT2LMHeadModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFGPT2LMHeadModel
+.. autoclass:: transformers.TFGPT2LMHeadModel
     :members:
 
 
 ``TFGPT2DoubleHeadsModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFGPT2DoubleHeadsModel
+.. autoclass:: transformers.TFGPT2DoubleHeadsModel
     :members:

docs/source/model_doc/roberta.rst

@@ -39,19 +39,19 @@ RoBERTa
 ``TFRobertaModel``
 ~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFRobertaModel
+.. autoclass:: transformers.TFRobertaModel
     :members:
 
 
 ``TFRobertaForMaskedLM``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFRobertaForMaskedLM
+.. autoclass:: transformers.TFRobertaForMaskedLM
     :members:
 
 
 ``TFRobertaForSequenceClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFRobertaForSequenceClassification
+.. autoclass:: transformers.TFRobertaForSequenceClassification
     :members:

docs/source/model_doc/transformerxl.rst

@@ -33,12 +33,12 @@ Transformer XL
 ``TFTransfoXLModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFTransfoXLModel
+.. autoclass:: transformers.TFTransfoXLModel
     :members:
 
 
 ``TFTransfoXLLMHeadModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFTransfoXLLMHeadModel
+.. autoclass:: transformers.TFTransfoXLLMHeadModel
     :members:

docs/source/model_doc/xlm.rst

@@ -44,26 +44,26 @@ XLM
 ``TFXLMModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLMModel
+.. autoclass:: transformers.TFXLMModel
     :members:
 
 
 ``TFXLMWithLMHeadModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLMWithLMHeadModel
+.. autoclass:: transformers.TFXLMWithLMHeadModel
     :members:
 
 
 ``TFXLMForSequenceClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLMForSequenceClassification
+.. autoclass:: transformers.TFXLMForSequenceClassification
     :members:
 
 
 ``TFXLMForQuestionAnsweringSimple``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLMForQuestionAnsweringSimple
+.. autoclass:: transformers.TFXLMForQuestionAnsweringSimple
     :members:

docs/source/model_doc/xlnet.rst

@@ -46,26 +46,26 @@ XLNet
 ``TFXLNetModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLNetModel
+.. autoclass:: transformers.TFXLNetModel
     :members:
 
 
 ``TFXLNetLMHeadModel``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLNetLMHeadModel
+.. autoclass:: transformers.TFXLNetLMHeadModel
     :members:
 
 
 ``TFXLNetForSequenceClassification``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLNetForSequenceClassification
+.. autoclass:: transformers.TFXLNetForSequenceClassification
     :members:
 
 
 ``TFXLNetForQuestionAnsweringSimple``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. autoclass:: pytorch_transformers.TFXLNetForQuestionAnsweringSimple
+.. autoclass:: transformers.TFXLNetForQuestionAnsweringSimple
     :members:

docs/source/multilingual.rst

@@ -0,0 +1,103 @@
+Multi-lingual models
+================================================
+
+Most of the models available in this library are mono-lingual models (English, Chinese and German). A few
+multi-lingual models are available and have a different mechanisms than mono-lingual models.
+This page details the usage of these models.
+
+The two models that currently support multiple languages are BERT and XLM.
+
+XLM
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+XLM has a total of 10 different checkpoints, only one of which is mono-lingual. The 9 remaining model checkpoints can
+be split in two categories: the checkpoints that make use of language embeddings, and those that don't
+
+XLM & Language Embeddings
+------------------------------------------------
+
+This section concerns the following checkpoints:
+
+- ``xlm-mlm-ende-1024`` (Masked language modeling, English-German)
+- ``xlm-mlm-enfr-1024`` (Masked language modeling, English-French)
+- ``xlm-mlm-enro-1024`` (Masked language modeling, English-Romanian)
+- ``xlm-mlm-xnli15-1024`` (Masked language modeling, XNLI languages)
+- ``xlm-mlm-tlm-xnli15-1024`` (Masked language modeling + Translation, XNLI languages)
+- ``xlm-clm-enfr-1024`` (Causal language modeling, English-French)
+- ``xlm-clm-ende-1024`` (Causal language modeling, English-German)
+
+These checkpoints require language embeddings that will specify the language used at inference time. These language
+embeddings are represented as a tensor that is of the same shape as the input ids passed to the model. The values in
+these tensors depend on the language used and are identifiable using the ``lang2id`` and ``id2lang`` attributes
+from the tokenizer.
+
+Here is an example using the ``xlm-clm-enfr-1024`` checkpoint (Causal language modeling, English-French):
+
+
+.. code-block::
+
+    import torch
+    from transformers import XLMTokenizer, XLMWithLMHeadModel
+
+    tokenizer = XLMTokenizer.from_pretrained("xlm-clm-1024-enfr")
+
+
+The different languages this model/tokenizer handles, as well as the ids of these languages are visible using the
+``lang2id`` attribute:
+
+.. code-block::
+
+    print(tokenizer.lang2id)  # {'en': 0, 'fr': 1}
+
+
+These ids should be used when passing a language parameter during a model pass. Let's define our inputs:
+
+.. code-block::
+
+    input_ids = torch.tensor([tokenizer.encode("Wikipedia was used to")]) # batch size of 1
+
+
+We should now define the language embedding by using the previously defined language id. We want to create a tensor
+filled with the appropriate language ids, of the same size as input_ids. For english, the id is 0:
+
+.. code-block::
+
+    language_id = tokenizer.lang2id['en']  # 0
+    langs = torch.tensor([language_id] * input_ids.shape[1])  # torch.tensor([0, 0, 0, ..., 0])
+
+    # We reshape it to be of size (batch_size, sequence_length)
+    langs = langs.view(1, -1) # is now of shape [1, sequence_length] (we have a batch size of 1)
+
+
+You can then feed it all as input to your model:
+
+.. code-block::
+
+    outputs = model(input_ids, langs=langs)
+
+
+The example `run_generation.py <https://github.com/huggingface/transformers/blob/master/examples/run_generation.py>`__
+can generate text using the CLM checkpoints from XLM, using the language embeddings.
+
+XLM without Language Embeddings
+------------------------------------------------
+
+This section concerns the following checkpoints:
+
+- ``xlm-mlm-17-1280`` (Masked language modeling, 17 languages)
+- ``xlm-mlm-100-1280`` (Masked language modeling, 100 languages)
+
+These checkpoints do not require language embeddings at inference time. These models are used to have generic
+sentence representations, differently from previously-mentioned XLM checkpoints.
+
+
+BERT
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+BERT has two checkpoints that can be used for multi-lingual tasks:
+
+- ``bert-base-multilingual-uncased`` (Masked language modeling + Next sentence prediction, 102 languages)
+- ``bert-base-multilingual-cased`` (Masked language modeling + Next sentence prediction, 104 languages)
+
+These checkpoints do not require language embeddings at inference time. They should identify the language
+used in the context and infer accordingly.

docs/source/pretrained_models.rst

@@ -98,6 +98,12 @@ Here is the full list of the currently provided pretrained models together with
 |                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
 |                   | ``xlm-clm-ende-1024``                                      | | 6-layer, 1024-hidden, 8-heads                                                                                                       |
 |                   |                                                            | | XLM English-German model trained with CLM (Causal Language Modeling) on the concatenation of English and German wikipedia           |
+|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                   | ``xlm-mlm-17-1280``                                        | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
+|                   |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 17 languages.                                                              |
+|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                   | ``xlm-mlm-100-1280``                                       | | 16-layer, 1280-hidden, 16-heads                                                                                                     |
+|                   |                                                            | | XLM model trained with MLM (Masked Language Modeling) on 100 languages.                                                             |
 +-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
 | RoBERTa           | ``roberta-base``                                           | | 12-layer, 768-hidden, 12-heads, 125M parameters                                                                                     |
 |                   |                                                            | | RoBERTa using the BERT-base architecture                                                                                            |
@@ -113,11 +119,18 @@ Here is the full list of the currently provided pretrained models together with
 +-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
 | DistilBERT        | ``distilbert-base-uncased``                                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
 |                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint                                                   |
-|                   |                                                            | (see `details <https://medium.com/huggingface/distilbert-8cf3380435b5>`__)                                                            |
+|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
 |                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
 |                   | ``distilbert-base-uncased-distilled-squad``                | | 6-layer, 768-hidden, 12-heads, 66M parameters                                                                                       |
 |                   |                                                            | | The DistilBERT model distilled from the BERT model `bert-base-uncased` checkpoint, with an additional linear layer.                 |
-|                   |                                                            | (see `details <https://medium.com/huggingface/distilbert-8cf3380435b5>`__)                                                            |
+|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
+|                   +------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+|                   | ``distilgpt2``                                             | | 6-layer, 768-hidden, 12-heads, 82M parameters                                                                                       |
+|                   |                                                            | | The DistilGPT2 model distilled from the GPT2 model `gpt2` checkpoint.                                                               |
+|                   |                                                            | (see `details <https://github.com/huggingface/transformers/tree/master/examples/distillation>`__)                                     |
++-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
+| CTRL              | ``ctrl``                                                   | | 48-layer, 1280-hidden, 16-heads, 1.6B parameters                                                                                    |
+|                   |                                                            | | Salesforce's Large-sized CTRL English model                                                                                         |
 +-------------------+------------------------------------------------------------+---------------------------------------------------------------------------------------------------------------------------------------+
 
 .. <https://huggingface.co/transformers/examples.html>`__

docs/source/quickstart.md

@@ -19,12 +19,12 @@ The library was designed with two strong goals in mind:
 
 A few other goals:
 
-- expose the models internals as consistently as possible:
+- expose the models' internals as consistently as possible:
 
   - we give access, using a single API to the full hidden-states and attention weights,
   - tokenizer and base model's API are standardized to easily switch between models.
 
-- incorporate a subjective selection of promising tools for fine-tuning/investiguating these models:
+- incorporate a subjective selection of promising tools for fine-tuning/investigating these models:
 
   - a simple/consistent way to add new tokens to the vocabulary and embeddings for fine-tuning,
   - simple ways to mask and prune transformer heads.
@@ -33,7 +33,7 @@ A few other goals:
 
 The library is build around three type of classes for each models:
 
-- **model classes** which are PyTorch models (`torch.nn.Modules`) of the 6 models architectures currently provided in the library, e.g. `BertModel`
+- **model classes** which are PyTorch models (`torch.nn.Modules`) of the 8 models architectures currently provided in the library, e.g. `BertModel`
 - **configuration classes** which store all the parameters required to build a model, e.g. `BertConfig`. You don't always need to instantiate these your-self, in particular if you are using a pretrained model without any modification, creating the model will automatically take care of instantiating the configuration (which is part of the model)
 - **tokenizer classes** which store the vocabulary for each model and provide methods for encoding/decoding strings in list of token embeddings indices to be fed to a model, e.g. `BertTokenizer`
 
@@ -51,7 +51,7 @@ We'll finish this quickstart tour by going through a few simple quick-start exam
 
 Here are two examples showcasing a few `Bert` and `GPT2` classes and pre-trained models.
 
-See full API reference for examples for each model classe.
+See full API reference for examples for each model class.
 
 ### BERT example
 
@@ -93,8 +93,8 @@ Let's see how we can use `BertModel` to encode our inputs in hidden-states:
 # Load pre-trained model (weights)
 model = BertModel.from_pretrained('bert-base-uncased')
 
-# Set the model in evaluation mode to desactivate the DropOut modules
-# This is IMPORTANT to have reproductible results during evaluation!
+# Set the model in evaluation mode to deactivate the DropOut modules
+# This is IMPORTANT to have reproducible results during evaluation!
 model.eval()
 
 # If you have a GPU, put everything on cuda
@@ -168,8 +168,8 @@ Let's see how to use `GPT2LMHeadModel` to generate the next token following our
 # Load pre-trained model (weights)
 model = GPT2LMHeadModel.from_pretrained('gpt2')
 
-# Set the model in evaluation mode to desactivate the DropOut modules
-# This is IMPORTANT to have reproductible results during evaluation!
+# Set the model in evaluation mode to deactivate the DropOut modules
+# This is IMPORTANT to have reproducible results during evaluation!
 model.eval()
 
 # If you have a GPU, put everything on cuda

examples/README.md

@@ -9,7 +9,7 @@ similar API between the different models.
 | [Language Generation](#language-generation) | Conditional text generation using the auto-regressive models of the library: GPT, GPT-2, Transformer-XL and XLNet.                                         |
 | [GLUE](#glue) | Examples running BERT/XLM/XLNet/RoBERTa on the 9 GLUE tasks. Examples feature distributed training as well as half-precision.                              |
 | [SQuAD](#squad) | Using BERT for question answering, examples with distributed training.                                                                                  |
-| [Multiple Choice](#multiple choice) | Examples running BERT/XLNet/RoBERTa on the SWAG/RACE/ARC tasks. 
+| [Multiple Choice](#multiple-choice) | Examples running BERT/XLNet/RoBERTa on the SWAG/RACE/ARC tasks. 
 
 ## Language model fine-tuning
 
@@ -283,17 +283,17 @@ The results  are the following:
   loss = 0.04755385363816904
 ```
 
-##Multiple Choice
+## Multiple Choice
 
 Based on the script [`run_multiple_choice.py`]().
 
 #### Fine-tuning on SWAG
 Download [swag](https://github.com/rowanz/swagaf/tree/master/data) data
 
-```
+```bash
 #training on 4 tesla V100(16GB) GPUS
 export SWAG_DIR=/path/to/swag_data_dir
-python ./examples/single_model_scripts/run_multiple_choice.py \
+python ./examples/run_multiple_choice.py \
 --model_type roberta \
 --task_name swag \
 --model_name_or_path roberta-base \

examples/distillation/README.md

@@ -1,22 +1,25 @@
-# DistilBERT
+# Distil*
 
-This folder contains the original code used to train DistilBERT as well as examples showcasing how to use DistilBERT.
+This folder contains the original code used to train Distil* as well as examples showcasing how to use DistilBERT and DistilGPT2.
+
+**2019, October 3rd - Update** We release our [NeurIPS workshop paper](https://arxiv.org/abs/1910.01108) explaining our approach on **DistilBERT**. It includes updated results and further experiments. We applied the same method to GPT2 and release the weights of **DistilGPT2**. DistilGPT2 is two times faster and 33% smaller than GPT2.
 
 **2019, September 19th - Update:** We fixed bugs in the code and released an upadted version of the weights trained with a modification of the distillation loss. DistilBERT now reaches 97% of `BERT-base`'s performance on GLUE, and 86.9 F1 score on SQuAD v1.1 dev set (compared to 88.5 for `BERT-base`). We will publish a formal write-up of our approach in the near future!
 
-## What is DistilBERT
+## What is Distil*
 
-DistilBERT stands for Distillated-BERT. DistilBERT is a small, fast, cheap and light Transformer model based on Bert architecture. It has 40% less parameters than `bert-base-uncased`, runs 60% faster while preserving 97% of BERT's performances as measured on the GLUE language understanding benchmark. DistilBERT is trained using knowledge distillation, a technique to compress a large model called the teacher into a smaller model called the student. By distillating Bert, we obtain a smaller Transformer model that bears a lot of similarities with the original BERT model while being lighter, smaller and faster to run. DistilBERT is thus an interesting option to put large-scaled trained Transformer model into production.
+Distil* is a class of compressed models that started with DistilBERT. DistilBERT stands for Distillated-BERT. DistilBERT is a small, fast, cheap and light Transformer model based on Bert architecture. It has 40% less parameters than `bert-base-uncased`, runs 60% faster while preserving 97% of BERT's performances as measured on the GLUE language understanding benchmark. DistilBERT is trained using knowledge distillation, a technique to compress a large model called the teacher into a smaller model called the student. By distillating Bert, we obtain a smaller Transformer model that bears a lot of similarities with the original BERT model while being lighter, smaller and faster to run. DistilBERT is thus an interesting option to put large-scaled trained Transformer model into production.
 
-For more information on DistilBERT, please refer to our [detailed blog post](https://medium.com/huggingface/smaller-faster-cheaper-lighter-introducing-distilbert-a-distilled-version-of-bert-8cf3380435b5
-). *Please note that we will publish a formal write-up with updated and more complete results in the near future (September 19th).*
+We have applied the same method to GPT2 and release the weights of the compressed model. On the [WikiText-103](https://blog.einstein.ai/the-wikitext-long-term-dependency-language-modeling-dataset/) benchmark, GPT2 reaches a perplexity on the test set of 15.0 compared to 18.5 for DistilGPT2 (after fine-tuning on the train set).
 
-Here's the updated results on the dev sets of GLUE:
+For more information on DistilBERT, please refer to our [NeurIPS workshop paper](https://arxiv.org/abs/1910.01108). The paper superseeds our [previous blogpost](https://medium.com/huggingface/distilbert-8cf3380435b5) with a different distillation loss and better performances.
 
-| Model      | Macro-score | CoLA | MNLI | MRPC | QNLI | QQP | RTE | SST-2 | STS-B | WNLI |
+Here are the results on the dev sets of GLUE:
+
+| Model      | Macro-score | CoLA | MNLI | MRPC | QNLI | QQP  | RTE  | SST-2| STS-B| WNLI |
 | :---:      |    :---:    | :---:| :---:| :---:| :---:| :---:| :---:| :---:| :---:| :---:|
 | BERT-base  |  **77.6**   | 48.9 | 84.3 | 88.6 | 89.3 | 89.5 | 71.3 | 91.7 | 91.2 | 43.7 |
-| DistilBERT |  **75.2**   | 49.1 | 81.8 | 90.2 | 87.0 | 89.2 | 62.9 | 92.7 | 90.7 | 44.4 |
+| DistilBERT |  **76.8**   | 49.1 | 81.8 | 90.2 | 90.2 | 89.2 | 62.9 | 92.7 | 90.7 | 44.4 |
 
 ## Setup
 
@@ -26,10 +29,12 @@ This part of the library has only be tested with Python3.6+. There are few speci
 
 ## How to use DistilBERT
 
-Transformers includes two pre-trained DistilBERT models, currently only provided for English (we are investigating the possibility to train and release a multilingual version of DistilBERT):
+Transformers includes two pre-trained Distil* models, currently only provided for English (we are investigating the possibility to train and release a multilingual version of DistilBERT):
 
 - `distilbert-base-uncased`: DistilBERT English language model pretrained on the same data used to pretrain Bert (concatenation of the Toronto Book Corpus and full English Wikipedia) using distillation with the supervision of the `bert-base-uncased` version of Bert. The model has 6 layers, 768 dimension and 12 heads, totalizing 66M parameters.
 - `distilbert-base-uncased-distilled-squad`: A finetuned version of `distilbert-base-uncased` finetuned using (a second step of) knwoledge distillation on SQuAD 1.0. This model reaches a F1 score of 86.9 on the dev set (for comparison, Bert `bert-base-uncased` version reaches a 88.5 F1 score).
+- `distilgpt2`: DistilGPT2 English language model pretrained with the supervision of `gpt2` (the smallest version of GPT2) on [OpenWebTextCorpus](https://skylion007.github.io/OpenWebTextCorpus/), a reproduction of OpenAI's WebText dataset and . The model has 6 layers, 768 dimension and 12 heads, totalizing 82M (compared to 124M parameters for GPT2). On average, DistilGPT2 is two times faster than GPT2.
+- and more to come! 🤗🤗🤗
 
 Using DistilBERT is very similar to using BERT. DistilBERT share the same tokenizer as BERT's `bert-base-uncased` even though we provide a link to this tokenizer under the `DistilBertTokenizer` name to have a consistent naming between the library models.
 
@@ -42,9 +47,11 @@ outputs = model(input_ids)
 last_hidden_states = outputs[0]  # The last hidden-state is the first element of the output tuple
 ```
 
-## How to train DistilBERT
+Similarly, using DistilGPT2 simply consists in calling the GPT2 classes from a different pretrained checkpoint: `model = GPT2Model.from_pretrained('distilgpt2')`.
 
-In the following, we will explain how you can train your own compressed model.
+## How to train Distil*
+
+In the following, we will explain how you can train DistilBERT.
 
 ### A. Preparing the data
 
@@ -57,7 +64,8 @@ First, we will binarize the data, i.e. tokenize the data and convert each token
 ```bash
 python scripts/binarized_data.py \
     --file_path data/dump.txt \
-    --bert_tokenizer bert-base-uncased \
+    --tokenizer_type bert \
+    --tokenizer_name bert-base-uncased \
     --dump_file data/binarized_text
 ```
 
@@ -66,7 +74,8 @@ Our implementation of masked language modeling loss follows [XLM](https://github
 ```bash
 python scripts/token_counts.py \
     --data_file data/binarized_text.bert-base-uncased.pickle \
-    --token_counts_dump data/token_counts.bert-base-uncased.pickle
+    --token_counts_dump data/token_counts.bert-base-uncased.pickle \
+    --vocab_size 30522
 ```
 
 ### B. Training
@@ -75,6 +84,12 @@ Training with distillation is really simple once you have pre-processed the data
 
 ```bash
 python train.py \
+    --student_type distilbert \
+    --student_config training_configs/distilbert-base-uncased.json \
+    --teacher_type bert \
+    --teacher_name bert-base-uncased \
+    --alpha_ce 5.0 --alpha_mlm 2.0 --alpha_cos 1.0 --mlm \
+    --freeze_pos_embs \
     --dump_path serialization_dir/my_first_training \
     --data_file data/binarized_text.bert-base-uncased.pickle \
     --token_counts data/token_counts.bert-base-uncased.pickle \
@@ -83,7 +98,7 @@ python train.py \
 
 By default, this will launch a training on a single GPU (even if more are available on the cluster). Other parameters are available in the command line, please look in `train.py` or run `python train.py --help` to list them.
 
-We highly encourage you to use distributed training for training DistilBert as the training corpus is quite large. Here's an example that runs a distributed training on a single node having 4 GPUs:
+We highly encourage you to use distributed training for training DistilBERT as the training corpus is quite large. Here's an example that runs a distributed training on a single node having 4 GPUs:
 
 ```bash
 export NODE_RANK=0
@@ -105,11 +120,17 @@ python -m torch.distributed.launch \
     train.py \
         --force \
         --n_gpu $WORLD_SIZE \
+        --student_type distilbert \
+        --student_config training_configs/distilbert-base-uncased.json \
+        --teacher_type bert \
+        --teacher_name bert-base-uncased \
+        --alpha_ce 0.33 --alpha_mlm 0.33 --alpha_cos 0.33 --mlm \
+        --freeze_pos_embs \
+        --dump_path serialization_dir/my_first_training \
         --data_file data/binarized_text.bert-base-uncased.pickle \
-        --token_counts data/token_counts.bert-base-uncased.pickle \
-        --dump_path serialization_dir/my_first_distillation
+        --token_counts data/token_counts.bert-base-uncased.pickle
 ```
 
-**Tips:** Starting distillated training with good initialization of the model weights is crucial to reach decent performance. In our experiments, we initialized our model from a few layers of the teacher (Bert) itself! Please refer to `scripts/extract_for_distil.py` to create a valid initialization checkpoint and use `--from_pretrained_weights` and `--from_pretrained_config` arguments to use this initialization for the distilled training!
+**Tips:** Starting distillated training with good initialization of the model weights is crucial to reach decent performance. In our experiments, we initialized our model from a few layers of the teacher (Bert) itself! Please refer to `scripts/extract.py` and `scripts/extract_distilbert.py` to create a valid initialization checkpoint and use `--student_pretrained_weights` argument to use this initialization for the distilled training!
 
 Happy distillation!

examples/distillation/distiller.py

@@ -12,8 +12,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" The distiller to distil DistilBERT
-    adapted in part from Facebook, Inc XLM model (https://github.com/facebookresearch/XLM)
+""" The distiller to distil the student.
+    Adapted in part from Facebook, Inc XLM model (https://github.com/facebookresearch/XLM)
 """
 import os
 import math
@@ -28,16 +28,19 @@ import torch
 import torch.nn as nn
 import torch.nn.functional as F
 from torch.optim import AdamW
+from torch.utils.data.distributed import DistributedSampler
+from torch.utils.data import RandomSampler, BatchSampler, DataLoader
 
 from transformers import WarmupLinearSchedule
 
 from utils import logger
-from dataset import Dataset
+from lm_seqs_dataset import LmSeqsDataset
+from grouped_batch_sampler import GroupedBatchSampler, create_lengths_groups
 
 class Distiller:
     def __init__(self,
                  params: dict,
-                 dataloader: Dataset,
+                 dataset: LmSeqsDataset,
                  token_probs: torch.tensor,
                  student: nn.Module,
                  teacher: nn.Module):
@@ -50,33 +53,47 @@ class Distiller:
         self.student = student
         self.teacher = teacher
 
-        self.dataloader = dataloader
-        if self.params.n_gpu > 1:
-            self.dataloader.split()
-        self.get_iterator(seed=params.seed)
+        self.student_config = student.config
+        self.vocab_size = student.config.vocab_size
+
+        if params.n_gpu <= 1:
+            sampler = RandomSampler(dataset)
+        else:
+            sampler = DistributedSampler(dataset)
+
+        if params.group_by_size:
+            groups = create_lengths_groups(lengths=dataset.lengths, k=params.max_model_input_size)
+            sampler = GroupedBatchSampler(sampler=sampler, group_ids=groups, batch_size=params.batch_size)
+        else:
+            sampler = BatchSampler(sampler=sampler, batch_size=params.batch_size, drop_last=False)
+
+        self.dataloader = DataLoader(dataset=dataset,
+                                     batch_sampler=sampler,
+                                     collate_fn=dataset.batch_sequences)
 
         self.temperature = params.temperature
         assert self.temperature > 0.
 
         self.alpha_ce = params.alpha_ce
         self.alpha_mlm = params.alpha_mlm
+        self.alpha_clm = params.alpha_clm
         self.alpha_mse = params.alpha_mse
         self.alpha_cos = params.alpha_cos
-        assert self.alpha_ce >= 0.
-        assert self.alpha_mlm >= 0.
-        assert self.alpha_mse >= 0.
-        assert self.alpha_cos >= 0.
-        assert self.alpha_ce + self.alpha_mlm + self.alpha_mse + self.alpha_cos > 0.
 
-        self.mlm_mask_prop = params.mlm_mask_prop
-        assert 0.0 <= self.mlm_mask_prop <= 1.0
-        assert params.word_mask + params.word_keep + params.word_rand == 1.0
-        self.pred_probs = torch.FloatTensor([params.word_mask, params.word_keep, params.word_rand])
-        self.pred_probs = self.pred_probs.to(f'cuda:{params.local_rank}') if params.n_gpu > 0 else self.pred_probs
-        self.token_probs = token_probs.to(f'cuda:{params.local_rank}') if params.n_gpu > 0 else token_probs
-        if self.fp16:
-            self.pred_probs = self.pred_probs.half()
-            self.token_probs = self.token_probs.half()
+        self.mlm = params.mlm
+        if self.mlm:
+            logger.info(f'Using MLM loss for LM step.')
+            self.mlm_mask_prop = params.mlm_mask_prop
+            assert 0.0 <= self.mlm_mask_prop <= 1.0
+            assert params.word_mask + params.word_keep + params.word_rand == 1.0
+            self.pred_probs = torch.FloatTensor([params.word_mask, params.word_keep, params.word_rand])
+            self.pred_probs = self.pred_probs.to(f'cuda:{params.local_rank}') if params.n_gpu > 0 else self.pred_probs
+            self.token_probs = token_probs.to(f'cuda:{params.local_rank}') if params.n_gpu > 0 else token_probs
+            if self.fp16:
+                self.pred_probs = self.pred_probs.half()
+                self.token_probs = self.token_probs.half()
+        else:
+            logger.info(f'Using CLM loss for LM step.')
 
         self.epoch = 0
         self.n_iter = 0
@@ -86,12 +103,13 @@ class Distiller:
         self.last_loss = 0
         self.last_loss_ce = 0
         self.last_loss_mlm = 0
+        self.last_loss_clm = 0
         if self.alpha_mse > 0.: self.last_loss_mse = 0
         if self.alpha_cos > 0.: self.last_loss_cos = 0
         self.last_log = 0
 
         self.ce_loss_fct = nn.KLDivLoss(reduction='batchmean')
-        self.mlm_loss_fct = nn.CrossEntropyLoss(ignore_index=-1)
+        self.lm_loss_fct = nn.CrossEntropyLoss(ignore_index=-1)
         if self.alpha_mse > 0.:
             self.mse_loss_fct = nn.MSELoss(reduction='sum')
         if self.alpha_cos > 0.:
@@ -99,7 +117,7 @@ class Distiller:
 
         logger.info('--- Initializing model optimizer')
         assert params.gradient_accumulation_steps >= 1
-        self.num_steps_epoch = int(len(self.dataloader) / params.batch_size) + 1
+        self.num_steps_epoch = len(self.dataloader)
         num_train_optimization_steps = int(self.num_steps_epoch / params.gradient_accumulation_steps * params.n_epoch) + 1
 
         no_decay = ['bias', 'LayerNorm.weight']
@@ -140,43 +158,18 @@ class Distiller:
                 logger.info("Using nn.parallel.DistributedDataParallel for distributed training.")
                 self.student = DistributedDataParallel(self.student,
                                                        device_ids=[params.local_rank],
-                                                       output_device=params.local_rank)
+                                                       output_device=params.local_rank,
+                                                       find_unused_parameters=True)
 
         self.is_master = params.is_master
         if self.is_master:
             logger.info('--- Initializing Tensorboard')
             self.tensorboard = SummaryWriter(log_dir=os.path.join(self.dump_path, 'log', 'train'))
-            self.tensorboard.add_text(tag='config', text_string=str(self.params), global_step=0)
+            self.tensorboard.add_text(tag='config/training', text_string=str(self.params), global_step=0)
+            self.tensorboard.add_text(tag='config/student', text_string=str(self.student_config), global_step=0)
 
-    def get_iterator(self,
-                     seed: int = None):
-        """
-        Initialize the data iterator.
-        Each process has its own data iterator (iterating on his own random portion of the dataset).
-
-        Input:
-        ------
-            seed: `int` - The random seed.
-        """
-        logger.info('--- Initializing Data Iterator')
-        self.data_iterator = self.dataloader.get_iterator(seed=seed)
-
-    def get_batch(self):
-        """
-        Call the data iterator to output a new batch.
-        If the data iterator went through the whole dataset, create a new iterator.
-        """
-        assert hasattr(self, 'data_iterator')
-        try:
-            x = next(self.data_iterator)
-        except StopIteration:
-            logger.warning('--- Went through the whole dataset. Creating new data iterator.')
-            self.data_iterator = self.dataloader.get_iterator()
-            x = next(self.data_iterator)
-        return x
-
-    def prepare_batch(self,
-                      batch):
+    def prepare_batch_mlm(self,
+                          batch):
         """
         Prepare the batch: from the token_ids and the lenghts, compute the attention mask and the masked label for MLM.
 
@@ -222,7 +215,7 @@ class Distiller:
                 assert pred_mask.sum().item() % 8 == 0, pred_mask.sum().item()
 
         _token_ids_real = token_ids[pred_mask]
-        _token_ids_rand = _token_ids_real.clone().random_(self.params.vocab_size)
+        _token_ids_rand = _token_ids_real.clone().random_(self.vocab_size)
         _token_ids_mask = _token_ids_real.clone().fill_(self.params.special_tok_ids['mask_token'])
         probs = torch.multinomial(self.pred_probs, len(_token_ids_real), replacement=True)
         _token_ids = _token_ids_mask * (probs == 0).long() + _token_ids_real * (probs == 1).long() + _token_ids_rand * (probs == 2).long()
@@ -230,8 +223,41 @@ class Distiller:
 
         mlm_labels[~pred_mask] = -1 # previously `mlm_labels[1-pred_mask] = -1`, cf pytorch 1.2.0 compatibility
 
+        # sanity checks
+        assert 0 <= token_ids.min() <= token_ids.max() < self.vocab_size
+
         return token_ids, attn_mask, mlm_labels
 
+    def prepare_batch_clm(self,
+                          batch):
+        """
+        Prepare the batch: from the token_ids and the lenghts, compute the attention mask and the labels for CLM.
+
+        Input:
+        ------
+            batch: `Tuple`
+                token_ids: `torch.tensor(bs, seq_length)` - The token ids for each of the sequence. It is padded.
+                lengths: `torch.tensor(bs)` - The lengths of each of the sequences in the batch.
+
+        Output:
+        -------
+            token_ids: `torch.tensor(bs, seq_length)` - The token ids after the modifications for MLM.
+            attn_mask: `torch.tensor(bs, seq_length)` - The attention mask for the self-attention.
+            clm_labels: `torch.tensor(bs, seq_length)` - The causal languge modeling labels. There is a -1 where there is nothing to predict.
+        """
+        token_ids, lengths = batch
+        token_ids, lengths = self.round_batch(x=token_ids, lengths=lengths)
+        assert token_ids.size(0) == lengths.size(0)
+
+        attn_mask = (torch.arange(token_ids.size(1), dtype=torch.long, device=lengths.device) < lengths[:, None])
+        clm_labels = token_ids.new(token_ids.size()).copy_(token_ids)
+        clm_labels[~attn_mask] = -1 # previously `clm_labels[1-attn_mask] = -1`, cf pytorch 1.2.0 compatibility
+
+        # sanity checks
+        assert 0 <= token_ids.min() <= token_ids.max() < self.vocab_size
+
+        return token_ids, attn_mask, clm_labels
+
     def round_batch(self,
                     x: torch.tensor,
                     lengths: torch.tensor):
@@ -269,7 +295,10 @@ class Distiller:
         if ml1 % 8 != 0:
             pad = 8 - (ml1 % 8)
             ml2 = ml1 + pad
-            pad_id = self.params.special_tok_ids['pad_token']
+            if self.mlm:
+                pad_id = self.params.special_tok_ids['pad_token']
+            else:
+                pad_id = self.params.special_tok_ids['unk_token']
             padding_tensor = torch.zeros(bs2, pad, dtype=torch.long, device=x.device).fill_(pad_id)
             x = torch.cat([x, padding_tensor], 1)
             assert x.size() == (bs2, ml2)
@@ -292,14 +321,16 @@ class Distiller:
             if self.multi_gpu:
                 torch.distributed.barrier()
 
-            iter_bar = trange(self.num_steps_epoch, desc="-Iter", disable=self.params.local_rank not in [-1, 0])
-            for __ in range(self.num_steps_epoch):
-                batch = self.get_batch()
+            iter_bar = tqdm(self.dataloader, desc="-Iter", disable=self.params.local_rank not in [-1, 0])
+            for batch in iter_bar:
                 if self.params.n_gpu > 0:
                     batch = tuple(t.to(f'cuda:{self.params.local_rank}') for t in batch)
-                token_ids, attn_mask, mlm_labels = self.prepare_batch(batch=batch)
 
-                self.step(input_ids=token_ids, attention_mask=attn_mask, mlm_labels=mlm_labels)
+                if self.mlm:
+                    token_ids, attn_mask, lm_labels = self.prepare_batch_mlm(batch=batch)
+                else:
+                    token_ids, attn_mask, lm_labels = self.prepare_batch_clm(batch=batch)
+                self.step(input_ids=token_ids, attention_mask=attn_mask, lm_labels=lm_labels)
 
                 iter_bar.update()
                 iter_bar.set_postfix({'Last_loss': f'{self.last_loss:.2f}',
@@ -317,7 +348,7 @@ class Distiller:
     def step(self,
              input_ids: torch.tensor,
              attention_mask: torch.tensor,
-             mlm_labels: torch.tensor):
+             lm_labels: torch.tensor):
         """
         One optimization step: forward of student AND teacher, backward on the loss (for gradient accumulation),
         and possibly a parameter update (depending on the gradient accumulation).
@@ -326,17 +357,22 @@ class Distiller:
         ------
         input_ids: `torch.tensor(bs, seq_length)` - The token ids.
         attention_mask: `torch.tensor(bs, seq_length)` - The attention mask for self attention.
-        mlm_labels: `torch.tensor(bs, seq_length)` - The masked language modeling labels.
+        lm_labels: `torch.tensor(bs, seq_length)` - The language modeling labels (mlm labels for MLM and clm labels for CLM).
         """
-        s_logits, s_hidden_states = self.student(input_ids=input_ids, attention_mask=attention_mask)     # (bs, seq_length, voc_size)
-        with torch.no_grad():
-            t_logits, t_hidden_states = self.teacher(input_ids=input_ids, attention_mask=attention_mask) # (bs, seq_length, voc_size)
+        if self.mlm:
+            s_logits, s_hidden_states = self.student(input_ids=input_ids, attention_mask=attention_mask)     # (bs, seq_length, voc_size)
+            with torch.no_grad():
+                t_logits, t_hidden_states = self.teacher(input_ids=input_ids, attention_mask=attention_mask) # (bs, seq_length, voc_size)
+        else:
+            s_logits, _, s_hidden_states = self.student(input_ids=input_ids, attention_mask=None)            # (bs, seq_length, voc_size)
+            with torch.no_grad():
+                t_logits, _, t_hidden_states = self.teacher(input_ids=input_ids, attention_mask=None)           # (bs, seq_length, voc_size)
         assert s_logits.size() == t_logits.size()
 
         #https://github.com/peterliht/knowledge-distillation-pytorch/blob/master/model/net.py#L100
         #https://github.com/peterliht/knowledge-distillation-pytorch/issues/2
         if self.params.restrict_ce_to_mask:
-            mask = (mlm_labels>-1).unsqueeze(-1).expand_as(s_logits)   # (bs, seq_lenth, voc_size)
+            mask = (lm_labels>-1).unsqueeze(-1).expand_as(s_logits)    # (bs, seq_lenth, voc_size)
         else:
             mask = attention_mask.unsqueeze(-1).expand_as(s_logits)    # (bs, seq_lenth, voc_size)
         s_logits_slct = torch.masked_select(s_logits, mask)            # (bs * seq_length * voc_size) modulo the 1s in mask
@@ -348,13 +384,20 @@ class Distiller:
         loss_ce = self.ce_loss_fct(F.log_softmax(s_logits_slct/self.temperature, dim=-1),
                                    F.softmax(t_logits_slct/self.temperature, dim=-1)) * (self.temperature)**2
         loss = self.alpha_ce*loss_ce
+
         if self.alpha_mlm > 0.:
-            loss_mlm = self.mlm_loss_fct(s_logits.view(-1, s_logits.size(-1)), mlm_labels.view(-1))
+            loss_mlm = self.lm_loss_fct(s_logits.view(-1, s_logits.size(-1)), lm_labels.view(-1))
             loss += self.alpha_mlm * loss_mlm
+        if self.alpha_clm > 0.:
+            shift_logits = s_logits[..., :-1, :].contiguous()
+            shift_labels = lm_labels[..., 1:].contiguous()
+            loss_clm = self.lm_loss_fct(shift_logits.view(-1, shift_logits.size(-1)),
+                                        shift_labels.view(-1))
+            loss += self.alpha_clm * loss_clm
+
         if self.alpha_mse > 0.:
             loss_mse = self.mse_loss_fct(s_logits_slct, t_logits_slct)/s_logits_slct.size(0) # Reproducing batchmean reduction
             loss += self.alpha_mse * loss_mse
-        
         if self.alpha_cos > 0.:
             s_hidden_states = s_hidden_states[-1]                              # (bs, seq_length, dim)
             t_hidden_states = t_hidden_states[-1]                              # (bs, seq_length, dim)
@@ -376,6 +419,8 @@ class Distiller:
         self.last_loss_ce = loss_ce.item()
         if self.alpha_mlm > 0.:
             self.last_loss_mlm = loss_mlm.item()
+        if self.alpha_clm > 0.:
+            self.last_loss_clm = loss_clm.item()
         if self.alpha_mse > 0.:
             self.last_loss_mse = loss_mse.item()
         if self.alpha_cos > 0.:
@@ -452,6 +497,8 @@ class Distiller:
         self.tensorboard.add_scalar(tag="losses/loss_ce", scalar_value=self.last_loss_ce, global_step=self.n_total_iter)
         if self.alpha_mlm > 0.:
             self.tensorboard.add_scalar(tag="losses/loss_mlm", scalar_value=self.last_loss_mlm, global_step=self.n_total_iter)
+        if self.alpha_clm > 0.:
+            self.tensorboard.add_scalar(tag="losses/loss_clm", scalar_value=self.last_loss_clm, global_step=self.n_total_iter)
         if self.alpha_mse > 0.:
             self.tensorboard.add_scalar(tag="losses/loss_mse", scalar_value=self.last_loss_mse, global_step=self.n_total_iter)
         if self.alpha_cos > 0.:

examples/distillation/grouped_batch_sampler.py

@@ -0,0 +1,105 @@
+# coding=utf-8
+# Copyright 2019-present, the HuggingFace Inc. team and Facebook, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" Adapted from PyTorch Vision (https://github.com/pytorch/vision/blob/master/references/detection/group_by_aspect_ratio.py)
+"""
+import bisect
+import copy
+from collections import defaultdict
+import numpy as np
+
+from torch.utils.data.sampler import BatchSampler, Sampler
+
+from utils import logger
+
+def _quantize(x, bins):
+    bins = copy.deepcopy(bins)
+    bins = sorted(bins)
+    quantized = list(map(lambda y: bisect.bisect_right(bins, y), x))
+    return quantized
+
+def create_lengths_groups(lengths, k=0):
+    bins = np.arange(start=3, stop=k, step=4).tolist() if k > 0 else [10]
+    groups = _quantize(lengths, bins)
+    # count number of elements per group
+    counts = np.unique(groups, return_counts=True)[1]
+    fbins = [0] + bins + [np.inf]
+    logger.info("Using {} as bins for aspect lengths quantization".format(fbins))
+    logger.info("Count of instances per bin: {}".format(counts))
+    return groups
+
+class GroupedBatchSampler(BatchSampler):
+    """
+    Wraps another sampler to yield a mini-batch of indices.
+    It enforces that the batch only contain elements from the same group.
+    It also tries to provide mini-batches which follows an ordering which is
+    as close as possible to the ordering from the original sampler.
+    Arguments:
+        sampler (Sampler): Base sampler.
+        group_ids (list[int]): If the sampler produces indices in range [0, N),
+            `group_ids` must be a list of `N` ints which contains the group id of each sample.
+            The group ids must be a continuous set of integers starting from
+            0, i.e. they must be in the range [0, num_groups).
+        batch_size (int): Size of mini-batch.
+    """
+    def __init__(self, sampler, group_ids, batch_size):
+        if not isinstance(sampler, Sampler):
+            raise ValueError(
+                "sampler should be an instance of "
+                "torch.utils.data.Sampler, but got sampler={}".format(sampler)
+            )
+        self.sampler = sampler
+        self.group_ids = group_ids
+        self.batch_size = batch_size
+
+    def __iter__(self):
+        buffer_per_group = defaultdict(list)
+        samples_per_group = defaultdict(list)
+
+        num_batches = 0
+        for idx in self.sampler:
+            group_id = self.group_ids[idx]
+            buffer_per_group[group_id].append(idx)
+            samples_per_group[group_id].append(idx)
+            if len(buffer_per_group[group_id]) == self.batch_size:
+                yield buffer_per_group[group_id] #TODO
+                num_batches += 1
+                del buffer_per_group[group_id]
+            assert len(buffer_per_group[group_id]) < self.batch_size
+
+        # now we have run out of elements that satisfy
+        # the group criteria, let's return the remaining
+        # elements so that the size of the sampler is
+        # deterministic
+        expected_num_batches = len(self)
+        num_remaining = expected_num_batches - num_batches
+        if num_remaining > 0:
+            # for the remaining batches, group the batches by similar lengths
+            batch_idx = []
+            for group_id, idxs in sorted(buffer_per_group.items(), key=lambda x: x[0]):
+                batch_idx.extend(idxs)
+                if len(batch_idx) >= self.batch_size:
+                    yield batch_idx[:self.batch_size]
+                    batch_idx = batch_idx[self.batch_size:]
+                    num_remaining -= 1
+            if len(batch_idx) > 0:
+                yield batch_idx
+                num_remaining -= 1
+        assert num_remaining == 0
+
+    def __len__(self):
+        """
+        Return the number of mini-batches rather than the number of samples.
+        """
+        return (len(self.sampler) + self.batch_size - 1) // self.batch_size

examples/distillation/lm_seqs_dataset.py

@@ -12,30 +12,33 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" Dataloaders to train DistilBERT
+""" Dataset to distilled models
     adapted in part from Facebook, Inc XLM model (https://github.com/facebookresearch/XLM)
 """
-from typing import List
-import math
-from itertools import chain
-from collections import Counter
-import numpy as np
 import torch
+from torch.utils.data import Dataset
 
+import numpy as np
 from utils import logger
 
-class Dataset:
+class LmSeqsDataset(Dataset):
+    """Custom Dataset wrapping language modeling sequences.
+
+    Each sample will be retrieved by indexing the list of token_ids and their corresponding lengths.
+
+    Input:
+    ------
+        params: `NameSpace` parameters
+        data: `List[np.array[int]]
+    """
+
     def __init__(self,
                  params,
                  data):
         self.params = params
-        self.tokens_per_batch = params.tokens_per_batch
-        self.batch_size = params.batch_size
-        self.shuffle = params.shuffle
-        self.group_by_size = params.group_by_size
 
         self.token_ids = np.array(data)
-        self.lengths = np.uint16([len(t) for t in data])
+        self.lengths = np.array([len(t) for t in data])
 
         self.check()
         self.remove_long_sequences()
@@ -43,6 +46,9 @@ class Dataset:
         self.check()
         self.print_statistics()
 
+    def __getitem__(self, index):
+        return (self.token_ids[index], self.lengths[index])
+
     def __len__(self):
         return len(self.lengths)
 
@@ -51,12 +57,14 @@ class Dataset:
         Some sanity checks
         """
         assert len(self.token_ids) == len(self.lengths)
+        assert all(self.lengths[i] == len(self.token_ids[i]) for i in range(len(self.lengths))) 
 
     def remove_long_sequences(self):
         """
-        Sequences that are too long are splitted by chunk of max_position_embeddings.
+        Sequences that are too long are splitted by chunk of max_model_input_size.
         """
-        indices = self.lengths >= self.params.max_position_embeddings
+        max_len = self.params.max_model_input_size
+        indices = self.lengths > max_len
         logger.info(f'Splitting {sum(indices)} too long sequences.')
 
         def divide_chunks(l, n):
@@ -64,10 +72,13 @@ class Dataset:
 
         new_tok_ids = []
         new_lengths = []
-        cls_id, sep_id = self.params.special_tok_ids['cls_token'], self.params.special_tok_ids['sep_token']
-        max_len = self.params.max_position_embeddings
+        if self.params.mlm:
+            cls_id, sep_id = self.params.special_tok_ids['cls_token'], self.params.special_tok_ids['sep_token']
+        else:
+            cls_id, sep_id = self.params.special_tok_ids['bos_token'], self.params.special_tok_ids['eos_token']
 
         for seq_, len_ in zip(self.token_ids, self.lengths):
+            assert (seq_[0] == cls_id) and (seq_[-1] == sep_id), seq_
             if len_ <= max_len:
                 new_tok_ids.append(seq_)
                 new_lengths.append(len_)
@@ -79,6 +90,7 @@ class Dataset:
                     if sub_s[-1] != sep_id:
                         sub_s = np.insert(sub_s, len(sub_s), sep_id)
                     assert len(sub_s) <= max_len
+                    assert (sub_s[0] == cls_id) and (sub_s[-1] == sep_id), sub_s
                     sub_seqs.append(sub_s)
 
                 new_tok_ids.extend(sub_seqs)
@@ -113,89 +125,27 @@ class Dataset:
         # nb_unkown = sum([(t==unk_idx).sum() for t in self.token_ids])
         # logger.info(f'{nb_unkown} unknown tokens (covering {100*nb_unkown/data_len:.2f}% of the data)')
 
-    def select_data(self, a: int, b: int):
-        """
-        Select a subportion of the data.
-        """
-        n_sequences = len(self)
-        assert 0 <= a < b <= n_sequences, ValueError(f'`0 <= a < b <= n_sequences` is not met with a={a} and b={b}')
-
-        logger.info(f'Selecting sequences from {a} to {b} (excluded).')
-        self.token_ids = self.token_ids[a:b]
-        self.lengths = self.lengths[a:b]
-
-        self.check()
-
-    def split(self):
-        """
-        Distributed training: split the data accross the processes.
-        """
-        assert self.params.n_gpu > 1
-        logger.info('Splitting the data accross the processuses.')
-        n_seq = len(self)
-        n_seq_per_procesus = n_seq // self.params.world_size
-        a = n_seq_per_procesus * self.params.global_rank
-        b = a + n_seq_per_procesus
-        self.select_data(a=a, b=b)
-
     def batch_sequences(self,
-                        token_ids: List[List[int]],
-                        lengths: List[int]):
+                        batch):
         """
         Do the padding and transform into torch.tensor.
         """
+        token_ids = [t[0] for t in batch]
+        lengths = [t[1] for t in batch]
         assert len(token_ids) == len(lengths)
 
         # Max for paddings
         max_seq_len_ = max(lengths)
 
         # Pad token ids
-        pad_idx = self.params.special_tok_ids['pad_token']
+        if self.params.mlm:
+            pad_idx = self.params.special_tok_ids['pad_token']
+        else:
+            pad_idx = self.params.special_tok_ids['unk_token']
         tk_ = [list(t.astype(int)) + [pad_idx]*(max_seq_len_-len(t)) for t in token_ids]
         assert len(tk_) == len(token_ids)
         assert all(len(t) == max_seq_len_ for t in tk_)
 
-        tk_t = torch.tensor(tk_)                  # (bs, max_seq_len_)
-        lg_t = torch.tensor(lengths.astype(int))  # (bs)
+        tk_t = torch.tensor(tk_)      # (bs, max_seq_len_)
+        lg_t = torch.tensor(lengths)  # (bs)
         return tk_t, lg_t
-
-    def get_batches_iterator(self,
-                             batches):
-        """
-        Return an iterator over batches.
-        """
-        for sequences_ids in batches:
-            token_ids, lengths = self.batch_sequences(self.token_ids[sequences_ids],
-                                                    self.lengths[sequences_ids])
-            yield (token_ids, lengths)
-
-    def get_iterator(self,
-                     seed: int = None):
-        """
-        Return a data iterator.
-        """
-        rng = np.random.RandomState(seed)
-
-        n_sequences = len(self)
-        indices = np.arange(n_sequences)
-
-        if self.group_by_size:
-            indices = indices[np.argsort(self.lengths[indices], kind='mergesort')]
-
-        if self.tokens_per_batch == -1:
-            batches = np.array_split(indices, math.ceil(len(indices) * 1. / self.batch_size))
-        else:
-            assert self.tokens_per_batch > 0
-            batch_ids = np.cumsum(self.lengths[indices]) // self.tokens_per_batch
-            _, bounds = np.unique(batch_ids, return_index=True)
-            batches = [indices[bounds[i]:bounds[i + 1]] for i in range(len(bounds) - 1)]
-            if bounds[-1] < len(indices):
-                batches.append(indices[bounds[-1]:])
-
-        if self.shuffle:
-            rng.shuffle(batches)
-
-        assert n_sequences == sum([len(x) for x in batches])
-        assert self.lengths[indices].sum() == sum([self.lengths[x].sum() for x in batches])
-
-        return self.get_batches_iterator(batches=batches)

examples/distillation/requirements.txt

@@ -3,4 +3,4 @@ tensorboard>=1.14.0
 tensorboardX==1.8
 psutil==5.6.3
 scipy==1.3.1
-pytorch_transformers==1.2.0
+transformers==2.0.0

examples/distillation/run_squad_w_distillation.py

@@ -0,0 +1,585 @@
+# coding=utf-8
+# Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
+# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" This is the exact same script as `examples/run_squad.py` (as of 2019, October 4th) with an additional and optional step of distillation."""
+
+from __future__ import absolute_import, division, print_function
+
+import argparse
+import logging
+import os
+import random
+import glob
+
+import numpy as np
+import torch
+from torch.utils.data import (DataLoader, RandomSampler, SequentialSampler,
+                              TensorDataset)
+from torch.utils.data.distributed import DistributedSampler
+import torch.nn.functional as F
+import torch.nn as nn
+from tqdm import tqdm, trange
+
+from tensorboardX import SummaryWriter
+
+from transformers import (WEIGHTS_NAME, BertConfig,
+                                  BertForQuestionAnswering, BertTokenizer,
+                                  XLMConfig, XLMForQuestionAnswering,
+                                  XLMTokenizer, XLNetConfig,
+                                  XLNetForQuestionAnswering,
+                                  XLNetTokenizer,
+                                  DistilBertConfig, DistilBertForQuestionAnswering, DistilBertTokenizer)
+
+from transformers import AdamW, WarmupLinearSchedule
+
+from ..utils_squad import (read_squad_examples, convert_examples_to_features,
+                         RawResult, write_predictions,
+                         RawResultExtended, write_predictions_extended)
+
+# The follwing import is the official SQuAD evaluation script (2.0).
+# You can remove it from the dependencies if you are using this script outside of the library
+# We've added it here for automated tests (see examples/test_examples.py file)
+from ..utils_squad_evaluate import EVAL_OPTS, main as evaluate_on_squad
+
+logger = logging.getLogger(__name__)
+
+ALL_MODELS = sum((tuple(conf.pretrained_config_archive_map.keys()) \
+                  for conf in (BertConfig, XLNetConfig, XLMConfig)), ())
+
+MODEL_CLASSES = {
+    'bert': (BertConfig, BertForQuestionAnswering, BertTokenizer),
+    'xlnet': (XLNetConfig, XLNetForQuestionAnswering, XLNetTokenizer),
+    'xlm': (XLMConfig, XLMForQuestionAnswering, XLMTokenizer),
+    'distilbert': (DistilBertConfig, DistilBertForQuestionAnswering, DistilBertTokenizer)
+}
+
+def set_seed(args):
+    random.seed(args.seed)
+    np.random.seed(args.seed)
+    torch.manual_seed(args.seed)
+    if args.n_gpu > 0:
+        torch.cuda.manual_seed_all(args.seed)
+
+def to_list(tensor):
+    return tensor.detach().cpu().tolist()
+
+def train(args, train_dataset, model, tokenizer, teacher=None):
+    """ Train the model """
+    if args.local_rank in [-1, 0]:
+        tb_writer = SummaryWriter()
+
+    args.train_batch_size = args.per_gpu_train_batch_size * max(1, args.n_gpu)
+    train_sampler = RandomSampler(train_dataset) if args.local_rank == -1 else DistributedSampler(train_dataset)
+    train_dataloader = DataLoader(train_dataset, sampler=train_sampler, batch_size=args.train_batch_size)
+
+    if args.max_steps > 0:
+        t_total = args.max_steps
+        args.num_train_epochs = args.max_steps // (len(train_dataloader) // args.gradient_accumulation_steps) + 1
+    else:
+        t_total = len(train_dataloader) // args.gradient_accumulation_steps * args.num_train_epochs
+
+    # Prepare optimizer and schedule (linear warmup and decay)
+    no_decay = ['bias', 'LayerNorm.weight']
+    optimizer_grouped_parameters = [
+        {'params': [p for n, p in model.named_parameters() if not any(nd in n for nd in no_decay)], 'weight_decay': args.weight_decay},
+        {'params': [p for n, p in model.named_parameters() if any(nd in n for nd in no_decay)], 'weight_decay': 0.0}
+        ]
+    optimizer = AdamW(optimizer_grouped_parameters, lr=args.learning_rate, eps=args.adam_epsilon)
+    scheduler = WarmupLinearSchedule(optimizer, warmup_steps=args.warmup_steps, t_total=t_total)
+    if args.fp16:
+        try:
+            from apex import amp
+        except ImportError:
+            raise ImportError("Please install apex from https://www.github.com/nvidia/apex to use fp16 training.")
+        model, optimizer = amp.initialize(model, optimizer, opt_level=args.fp16_opt_level)
+
+    # multi-gpu training (should be after apex fp16 initialization)
+    if args.n_gpu > 1:
+        model = torch.nn.DataParallel(model)
+
+    # Distributed training (should be after apex fp16 initialization)
+    if args.local_rank != -1:
+        model = torch.nn.parallel.DistributedDataParallel(model, device_ids=[args.local_rank],
+                                                          output_device=args.local_rank,
+                                                          find_unused_parameters=True)
+
+    # Train!
+    logger.info("***** Running training *****")
+    logger.info("  Num examples = %d", len(train_dataset))
+    logger.info("  Num Epochs = %d", args.num_train_epochs)
+    logger.info("  Instantaneous batch size per GPU = %d", args.per_gpu_train_batch_size)
+    logger.info("  Total train batch size (w. parallel, distributed & accumulation) = %d",
+                   args.train_batch_size * args.gradient_accumulation_steps * (torch.distributed.get_world_size() if args.local_rank != -1 else 1))
+    logger.info("  Gradient Accumulation steps = %d", args.gradient_accumulation_steps)
+    logger.info("  Total optimization steps = %d", t_total)
+
+    global_step = 0
+    tr_loss, logging_loss = 0.0, 0.0
+    model.zero_grad()
+    train_iterator = trange(int(args.num_train_epochs), desc="Epoch", disable=args.local_rank not in [-1, 0])
+    set_seed(args)  # Added here for reproductibility (even between python 2 and 3)
+    for _ in train_iterator:
+        epoch_iterator = tqdm(train_dataloader, desc="Iteration", disable=args.local_rank not in [-1, 0])
+        for step, batch in enumerate(epoch_iterator):
+            model.train()
+            if teacher is not None:
+                teacher.eval()
+            batch = tuple(t.to(args.device) for t in batch)
+            inputs = {'input_ids':       batch[0],
+                      'attention_mask':  batch[1], 
+                      'start_positions': batch[3], 
+                      'end_positions':   batch[4]}
+            if args.model_type != 'distilbert':
+                inputs['token_type_ids'] = None if args.model_type == 'xlm' else batch[2]
+            if args.model_type in ['xlnet', 'xlm']:
+                inputs.update({'cls_index': batch[5],
+                               'p_mask':       batch[6]})
+            outputs = model(**inputs)
+            loss, start_logits_stu, end_logits_stu = outputs
+
+            # Distillation loss
+            if teacher is not None:
+                if 'token_type_ids' not in inputs:
+                    inputs['token_type_ids'] = None if args.teacher_type == 'xlm' else batch[2]
+                with torch.no_grad():
+                    start_logits_tea, end_logits_tea = teacher(input_ids=inputs['input_ids'],
+                                                               token_type_ids=inputs['token_type_ids'],
+                                                               attention_mask=inputs['attention_mask'])
+                assert start_logits_tea.size() == start_logits_stu.size()
+                assert end_logits_tea.size() == end_logits_stu.size()
+                
+                loss_fct = nn.KLDivLoss(reduction='batchmean')
+                loss_start = loss_fct(F.log_softmax(start_logits_stu/args.temperature, dim=-1),
+                                      F.softmax(start_logits_tea/args.temperature, dim=-1)) * (args.temperature**2)
+                loss_end = loss_fct(F.log_softmax(end_logits_stu/args.temperature, dim=-1),
+                                    F.softmax(end_logits_tea/args.temperature, dim=-1)) * (args.temperature**2)
+                loss_ce = (loss_start + loss_end)/2.
+
+                loss = args.alpha_ce*loss_ce + args.alpha_squad*loss
+
+            if args.n_gpu > 1:
+                loss = loss.mean() # mean() to average on multi-gpu parallel (not distributed) training
+            if args.gradient_accumulation_steps > 1:
+                loss = loss / args.gradient_accumulation_steps
+
+            if args.fp16:
+                with amp.scale_loss(loss, optimizer) as scaled_loss:
+                    scaled_loss.backward()
+                torch.nn.utils.clip_grad_norm_(amp.master_params(optimizer), args.max_grad_norm)
+            else:
+                loss.backward()
+                torch.nn.utils.clip_grad_norm_(model.parameters(), args.max_grad_norm)
+
+            tr_loss += loss.item()
+            if (step + 1) % args.gradient_accumulation_steps == 0:
+                optimizer.step()
+                scheduler.step()  # Update learning rate schedule
+                model.zero_grad()
+                global_step += 1
+
+                if args.local_rank in [-1, 0] and args.logging_steps > 0 and global_step % args.logging_steps == 0:
+                    # Log metrics
+                    if args.local_rank == -1 and args.evaluate_during_training:  # Only evaluate when single GPU otherwise metrics may not average well
+                        results = evaluate(args, model, tokenizer)
+                        for key, value in results.items():
+                            tb_writer.add_scalar('eval_{}'.format(key), value, global_step)
+                    tb_writer.add_scalar('lr', scheduler.get_lr()[0], global_step)
+                    tb_writer.add_scalar('loss', (tr_loss - logging_loss)/args.logging_steps, global_step)
+                    logging_loss = tr_loss
+
+                if args.local_rank in [-1, 0] and args.save_steps > 0 and global_step % args.save_steps == 0:
+                    # Save model checkpoint
+                    output_dir = os.path.join(args.output_dir, 'checkpoint-{}'.format(global_step))
+                    if not os.path.exists(output_dir):
+                        os.makedirs(output_dir)
+                    model_to_save = model.module if hasattr(model, 'module') else model  # Take care of distributed/parallel training
+                    model_to_save.save_pretrained(output_dir)
+                    torch.save(args, os.path.join(output_dir, 'training_args.bin'))
+                    logger.info("Saving model checkpoint to %s", output_dir)
+
+            if args.max_steps > 0 and global_step > args.max_steps:
+                epoch_iterator.close()
+                break
+        if args.max_steps > 0 and global_step > args.max_steps:
+            train_iterator.close()
+            break
+
+    if args.local_rank in [-1, 0]:
+        tb_writer.close()
+
+    return global_step, tr_loss / global_step
+
+
+def evaluate(args, model, tokenizer, prefix=""):
+    dataset, examples, features = load_and_cache_examples(args, tokenizer, evaluate=True, output_examples=True)
+
+    if not os.path.exists(args.output_dir) and args.local_rank in [-1, 0]:
+        os.makedirs(args.output_dir)
+
+    args.eval_batch_size = args.per_gpu_eval_batch_size * max(1, args.n_gpu)
+    # Note that DistributedSampler samples randomly
+    eval_sampler = SequentialSampler(dataset) if args.local_rank == -1 else DistributedSampler(dataset)
+    eval_dataloader = DataLoader(dataset, sampler=eval_sampler, batch_size=args.eval_batch_size)
+
+    # Eval!
+    logger.info("***** Running evaluation {} *****".format(prefix))
+    logger.info("  Num examples = %d", len(dataset))
+    logger.info("  Batch size = %d", args.eval_batch_size)
+    all_results = []
+    for batch in tqdm(eval_dataloader, desc="Evaluating"):
+        model.eval()
+        batch = tuple(t.to(args.device) for t in batch)
+        with torch.no_grad():
+            inputs = {'input_ids':      batch[0],
+                      'attention_mask': batch[1]
+                      }
+            if args.model_type != 'distilbert':
+                inputs['token_type_ids'] = None if args.model_type == 'xlm' else batch[2]  # XLM don't use segment_ids
+            example_indices = batch[3]
+            if args.model_type in ['xlnet', 'xlm']:
+                inputs.update({'cls_index': batch[4],
+                               'p_mask':    batch[5]})
+            outputs = model(**inputs)
+
+        for i, example_index in enumerate(example_indices):
+            eval_feature = features[example_index.item()]
+            unique_id = int(eval_feature.unique_id)
+            if args.model_type in ['xlnet', 'xlm']:
+                # XLNet uses a more complex post-processing procedure
+                result = RawResultExtended(unique_id            = unique_id,
+                                           start_top_log_probs  = to_list(outputs[0][i]),
+                                           start_top_index      = to_list(outputs[1][i]),
+                                           end_top_log_probs    = to_list(outputs[2][i]),
+                                           end_top_index        = to_list(outputs[3][i]),
+                                           cls_logits           = to_list(outputs[4][i]))
+            else:
+                result = RawResult(unique_id    = unique_id,
+                                   start_logits = to_list(outputs[0][i]),
+                                   end_logits   = to_list(outputs[1][i]))
+            all_results.append(result)
+
+    # Compute predictions
+    output_prediction_file = os.path.join(args.output_dir, "predictions_{}.json".format(prefix))
+    output_nbest_file = os.path.join(args.output_dir, "nbest_predictions_{}.json".format(prefix))
+    if args.version_2_with_negative:
+        output_null_log_odds_file = os.path.join(args.output_dir, "null_odds_{}.json".format(prefix))
+    else:
+        output_null_log_odds_file = None
+
+    if args.model_type in ['xlnet', 'xlm']:
+        # XLNet uses a more complex post-processing procedure
+        write_predictions_extended(examples, features, all_results, args.n_best_size,
+                        args.max_answer_length, output_prediction_file,
+                        output_nbest_file, output_null_log_odds_file, args.predict_file,
+                        model.config.start_n_top, model.config.end_n_top,
+                        args.version_2_with_negative, tokenizer, args.verbose_logging)
+    else:
+        write_predictions(examples, features, all_results, args.n_best_size,
+                        args.max_answer_length, args.do_lower_case, output_prediction_file,
+                        output_nbest_file, output_null_log_odds_file, args.verbose_logging,
+                        args.version_2_with_negative, args.null_score_diff_threshold)
+
+    # Evaluate with the official SQuAD script
+    evaluate_options = EVAL_OPTS(data_file=args.predict_file,
+                                 pred_file=output_prediction_file,
+                                 na_prob_file=output_null_log_odds_file)
+    results = evaluate_on_squad(evaluate_options)
+    return results
+
+
+def load_and_cache_examples(args, tokenizer, evaluate=False, output_examples=False):
+    if args.local_rank not in [-1, 0] and not evaluate:
+        torch.distributed.barrier()  # Make sure only the first process in distributed training process the dataset, and the others will use the cache
+
+    # Load data features from cache or dataset file
+    input_file = args.predict_file if evaluate else args.train_file
+    cached_features_file = os.path.join(os.path.dirname(input_file), 'cached_{}_{}_{}'.format(
+        'dev' if evaluate else 'train',
+        list(filter(None, args.model_name_or_path.split('/'))).pop(),
+        str(args.max_seq_length)))
+    if os.path.exists(cached_features_file) and not args.overwrite_cache and not output_examples:
+        logger.info("Loading features from cached file %s", cached_features_file)
+        features = torch.load(cached_features_file)
+    else:
+        logger.info("Creating features from dataset file at %s", input_file)
+        examples = read_squad_examples(input_file=input_file,
+                                                is_training=not evaluate,
+                                                version_2_with_negative=args.version_2_with_negative)
+        features = convert_examples_to_features(examples=examples,
+                                                tokenizer=tokenizer,
+                                                max_seq_length=args.max_seq_length,
+                                                doc_stride=args.doc_stride,
+                                                max_query_length=args.max_query_length,
+                                                is_training=not evaluate)
+        if args.local_rank in [-1, 0]:
+            logger.info("Saving features into cached file %s", cached_features_file)
+            torch.save(features, cached_features_file)
+
+    if args.local_rank == 0 and not evaluate:
+        torch.distributed.barrier()  # Make sure only the first process in distributed training process the dataset, and the others will use the cache
+
+    # Convert to Tensors and build dataset
+    all_input_ids = torch.tensor([f.input_ids for f in features], dtype=torch.long)
+    all_input_mask = torch.tensor([f.input_mask for f in features], dtype=torch.long)
+    all_segment_ids = torch.tensor([f.segment_ids for f in features], dtype=torch.long)
+    all_cls_index = torch.tensor([f.cls_index for f in features], dtype=torch.long)
+    all_p_mask = torch.tensor([f.p_mask for f in features], dtype=torch.float)
+    if evaluate:
+        all_example_index = torch.arange(all_input_ids.size(0), dtype=torch.long)
+        dataset = TensorDataset(all_input_ids, all_input_mask, all_segment_ids,
+                                all_example_index, all_cls_index, all_p_mask)
+    else:
+        all_start_positions = torch.tensor([f.start_position for f in features], dtype=torch.long)
+        all_end_positions = torch.tensor([f.end_position for f in features], dtype=torch.long)
+        dataset = TensorDataset(all_input_ids, all_input_mask, all_segment_ids,
+                                all_start_positions, all_end_positions,
+                                all_cls_index, all_p_mask)
+
+    if output_examples:
+        return dataset, examples, features
+    return dataset
+
+
+def main():
+    parser = argparse.ArgumentParser()
+
+    ## Required parameters
+    parser.add_argument("--train_file", default=None, type=str, required=True,
+                        help="SQuAD json for training. E.g., train-v1.1.json")
+    parser.add_argument("--predict_file", default=None, type=str, required=True,
+                        help="SQuAD json for predictions. E.g., dev-v1.1.json or test-v1.1.json")
+    parser.add_argument("--model_type", default=None, type=str, required=True,
+                        help="Model type selected in the list: " + ", ".join(MODEL_CLASSES.keys()))
+    parser.add_argument("--model_name_or_path", default=None, type=str, required=True,
+                        help="Path to pre-trained model or shortcut name selected in the list: " + ", ".join(ALL_MODELS))
+    parser.add_argument("--output_dir", default=None, type=str, required=True,
+                        help="The output directory where the model checkpoints and predictions will be written.")
+
+    # Distillation parameters (optional)
+    parser.add_argument('--teacher_type', default=None, type=str,
+                        help="Teacher type. Teacher tokenizer and student (model) tokenizer must output the same tokenization. Only for distillation.")
+    parser.add_argument('--teacher_name_or_path', default=None, type=str,
+                        help="Path to the already SQuAD fine-tuned teacher model. Only for distillation.")
+    parser.add_argument('--alpha_ce', default=0.5, type=float,
+                        help="Distillation loss linear weight. Only for distillation.")
+    parser.add_argument('--alpha_squad', default=0.5, type=float,
+                        help="True SQuAD loss linear weight. Only for distillation.")
+    parser.add_argument('--temperature', default=2.0, type=float,
+                        help="Distillation temperature. Only for distillation.")
+
+    ## Other parameters
+    parser.add_argument("--config_name", default="", type=str,
+                        help="Pretrained config name or path if not the same as model_name")
+    parser.add_argument("--tokenizer_name", default="", type=str,
+                        help="Pretrained tokenizer name or path if not the same as model_name")
+    parser.add_argument("--cache_dir", default="", type=str,
+                        help="Where do you want to store the pre-trained models downloaded from s3")
+
+    parser.add_argument('--version_2_with_negative', action='store_true',
+                        help='If true, the SQuAD examples contain some that do not have an answer.')
+    parser.add_argument('--null_score_diff_threshold', type=float, default=0.0,
+                        help="If null_score - best_non_null is greater than the threshold predict null.")
+
+    parser.add_argument("--max_seq_length", default=384, type=int,
+                        help="The maximum total input sequence length after WordPiece tokenization. Sequences "
+                             "longer than this will be truncated, and sequences shorter than this will be padded.")
+    parser.add_argument("--doc_stride", default=128, type=int,
+                        help="When splitting up a long document into chunks, how much stride to take between chunks.")
+    parser.add_argument("--max_query_length", default=64, type=int,
+                        help="The maximum number of tokens for the question. Questions longer than this will "
+                             "be truncated to this length.")
+    parser.add_argument("--do_train", action='store_true',
+                        help="Whether to run training.")
+    parser.add_argument("--do_eval", action='store_true',
+                        help="Whether to run eval on the dev set.")
+    parser.add_argument("--evaluate_during_training", action='store_true',
+                        help="Rul evaluation during training at each logging step.")
+    parser.add_argument("--do_lower_case", action='store_true',
+                        help="Set this flag if you are using an uncased model.")
+
+    parser.add_argument("--per_gpu_train_batch_size", default=8, type=int,
+                        help="Batch size per GPU/CPU for training.")
+    parser.add_argument("--per_gpu_eval_batch_size", default=8, type=int,
+                        help="Batch size per GPU/CPU for evaluation.")
+    parser.add_argument("--learning_rate", default=5e-5, type=float,
+                        help="The initial learning rate for Adam.")
+    parser.add_argument('--gradient_accumulation_steps', type=int, default=1,
+                        help="Number of updates steps to accumulate before performing a backward/update pass.")
+    parser.add_argument("--weight_decay", default=0.0, type=float,
+                        help="Weight deay if we apply some.")
+    parser.add_argument("--adam_epsilon", default=1e-8, type=float,
+                        help="Epsilon for Adam optimizer.")
+    parser.add_argument("--max_grad_norm", default=1.0, type=float,
+                        help="Max gradient norm.")
+    parser.add_argument("--num_train_epochs", default=3.0, type=float,
+                        help="Total number of training epochs to perform.")
+    parser.add_argument("--max_steps", default=-1, type=int,
+                        help="If > 0: set total number of training steps to perform. Override num_train_epochs.")
+    parser.add_argument("--warmup_steps", default=0, type=int,
+                        help="Linear warmup over warmup_steps.")
+    parser.add_argument("--n_best_size", default=20, type=int,
+                        help="The total number of n-best predictions to generate in the nbest_predictions.json output file.")
+    parser.add_argument("--max_answer_length", default=30, type=int,
+                        help="The maximum length of an answer that can be generated. This is needed because the start "
+                             "and end predictions are not conditioned on one another.")
+    parser.add_argument("--verbose_logging", action='store_true',
+                        help="If true, all of the warnings related to data processing will be printed. "
+                             "A number of warnings are expected for a normal SQuAD evaluation.")
+
+    parser.add_argument('--logging_steps', type=int, default=50,
+                        help="Log every X updates steps.")
+    parser.add_argument('--save_steps', type=int, default=50,
+                        help="Save checkpoint every X updates steps.")
+    parser.add_argument("--eval_all_checkpoints", action='store_true',
+                        help="Evaluate all checkpoints starting with the same prefix as model_name ending and ending with step number")
+    parser.add_argument("--no_cuda", action='store_true',
+                        help="Whether not to use CUDA when available")
+    parser.add_argument('--overwrite_output_dir', action='store_true',
+                        help="Overwrite the content of the output directory")
+    parser.add_argument('--overwrite_cache', action='store_true',
+                        help="Overwrite the cached training and evaluation sets")
+    parser.add_argument('--seed', type=int, default=42,
+                        help="random seed for initialization")
+
+    parser.add_argument("--local_rank", type=int, default=-1,
+                        help="local_rank for distributed training on gpus")
+    parser.add_argument('--fp16', action='store_true',
+                        help="Whether to use 16-bit (mixed) precision (through NVIDIA apex) instead of 32-bit")
+    parser.add_argument('--fp16_opt_level', type=str, default='O1',
+                        help="For fp16: Apex AMP optimization level selected in ['O0', 'O1', 'O2', and 'O3']."
+                             "See details at https://nvidia.github.io/apex/amp.html")
+    parser.add_argument('--server_ip', type=str, default='', help="Can be used for distant debugging.")
+    parser.add_argument('--server_port', type=str, default='', help="Can be used for distant debugging.")
+    args = parser.parse_args()
+
+    if os.path.exists(args.output_dir) and os.listdir(args.output_dir) and args.do_train and not args.overwrite_output_dir:
+        raise ValueError("Output directory ({}) already exists and is not empty. Use --overwrite_output_dir to overcome.".format(args.output_dir))
+
+    # Setup distant debugging if needed
+    if args.server_ip and args.server_port:
+        # Distant debugging - see https://code.visualstudio.com/docs/python/debugging#_attach-to-a-local-script
+        import ptvsd
+        print("Waiting for debugger attach")
+        ptvsd.enable_attach(address=(args.server_ip, args.server_port), redirect_output=True)
+        ptvsd.wait_for_attach()
+
+    # Setup CUDA, GPU & distributed training
+    if args.local_rank == -1 or args.no_cuda:
+        device = torch.device("cuda" if torch.cuda.is_available() and not args.no_cuda else "cpu")
+        args.n_gpu = torch.cuda.device_count()
+    else:  # Initializes the distributed backend which will take care of sychronizing nodes/GPUs
+        torch.cuda.set_device(args.local_rank)
+        device = torch.device("cuda", args.local_rank)
+        torch.distributed.init_process_group(backend='nccl')
+        args.n_gpu = 1
+    args.device = device
+
+    # Setup logging
+    logging.basicConfig(format = '%(asctime)s - %(levelname)s - %(name)s -   %(message)s',
+                        datefmt = '%m/%d/%Y %H:%M:%S',
+                        level = logging.INFO if args.local_rank in [-1, 0] else logging.WARN)
+    logger.warning("Process rank: %s, device: %s, n_gpu: %s, distributed training: %s, 16-bits training: %s",
+                    args.local_rank, device, args.n_gpu, bool(args.local_rank != -1), args.fp16)
+
+    # Set seed
+    set_seed(args)
+
+    # Load pretrained model and tokenizer
+    if args.local_rank not in [-1, 0]:
+        torch.distributed.barrier()  # Make sure only the first process in distributed training will download model & vocab
+
+    args.model_type = args.model_type.lower()
+    config_class, model_class, tokenizer_class = MODEL_CLASSES[args.model_type]
+    config = config_class.from_pretrained(args.config_name if args.config_name else args.model_name_or_path)
+    tokenizer = tokenizer_class.from_pretrained(args.tokenizer_name if args.tokenizer_name else args.model_name_or_path, do_lower_case=args.do_lower_case)
+    model = model_class.from_pretrained(args.model_name_or_path, from_tf=bool('.ckpt' in args.model_name_or_path), config=config)
+
+    if args.teacher_type is not None:
+        assert args.teacher_name_or_path is not None
+        assert args.alpha_ce > 0.
+        assert args.alpha_ce + args.alpha_squad > 0.
+        assert args.teacher_type != 'distilbert', "We constraint teachers not to be of type DistilBERT."
+        teacher_config_class, teacher_model_class, _ = MODEL_CLASSES[args.teacher_type]
+        teacher_config = teacher_config_class.from_pretrained(args.teacher_name_or_path)
+        teacher = teacher_model_class.from_pretrained(args.teacher_name_or_path, config=teacher_config)
+        teacher.to(args.device)
+    else:
+        teacher = None
+
+    if args.local_rank == 0:
+        torch.distributed.barrier()  # Make sure only the first process in distributed training will download model & vocab
+
+    model.to(args.device)
+
+    logger.info("Training/evaluation parameters %s", args)
+
+    # Training
+    if args.do_train:
+        train_dataset = load_and_cache_examples(args, tokenizer, evaluate=False, output_examples=False)
+        global_step, tr_loss = train(args, train_dataset, model, tokenizer, teacher=teacher)
+        logger.info(" global_step = %s, average loss = %s", global_step, tr_loss)
+
+
+    # Save the trained model and the tokenizer
+    if args.do_train and (args.local_rank == -1 or torch.distributed.get_rank() == 0):
+        # Create output directory if needed
+        if not os.path.exists(args.output_dir) and args.local_rank in [-1, 0]:
+            os.makedirs(args.output_dir)
+
+        logger.info("Saving model checkpoint to %s", args.output_dir)
+        # Save a trained model, configuration and tokenizer using `save_pretrained()`.
+        # They can then be reloaded using `from_pretrained()`
+        model_to_save = model.module if hasattr(model, 'module') else model  # Take care of distributed/parallel training
+        model_to_save.save_pretrained(args.output_dir)
+        tokenizer.save_pretrained(args.output_dir)
+
+        # Good practice: save your training arguments together with the trained model
+        torch.save(args, os.path.join(args.output_dir, 'training_args.bin'))
+
+        # Load a trained model and vocabulary that you have fine-tuned
+        model = model_class.from_pretrained(args.output_dir)
+        tokenizer = tokenizer_class.from_pretrained(args.output_dir, do_lower_case=args.do_lower_case)
+        model.to(args.device)
+
+
+    # Evaluation - we can ask to evaluate all the checkpoints (sub-directories) in a directory
+    results = {}
+    if args.do_eval and args.local_rank in [-1, 0]:
+        checkpoints = [args.output_dir]
+        if args.eval_all_checkpoints:
+            checkpoints = list(os.path.dirname(c) for c in sorted(glob.glob(args.output_dir + '/**/' + WEIGHTS_NAME, recursive=True)))
+            logging.getLogger("transformers.modeling_utils").setLevel(logging.WARN)  # Reduce model loading logs
+
+        logger.info("Evaluate the following checkpoints: %s", checkpoints)
+
+        for checkpoint in checkpoints:
+            # Reload the model
+            global_step = checkpoint.split('-')[-1] if len(checkpoints) > 1 else ""
+            model = model_class.from_pretrained(checkpoint)
+            model.to(args.device)
+
+            # Evaluate
+            result = evaluate(args, model, tokenizer, prefix=global_step)
+
+            result = dict((k + ('_{}'.format(global_step) if global_step else ''), v) for k, v in result.items())
+            results.update(result)
+
+    logger.info("Results: {}".format(results))
+
+    return results
+
+
+if __name__ == "__main__":
+    main()

examples/distillation/scripts/binarized_data.py

@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """
-Preprocessing script before training DistilBERT.
+Preprocessing script before distillation.
 """
 import argparse
 import pickle
 import random
 import time
 import numpy as np
-from transformers import BertTokenizer, RobertaTokenizer
+from transformers import BertTokenizer, RobertaTokenizer, GPT2Tokenizer
 import logging
 
 logging.basicConfig(format = '%(asctime)s - %(levelname)s - %(name)s -   %(message)s',
@@ -32,7 +32,7 @@ def main():
     parser = argparse.ArgumentParser(description="Preprocess the data to avoid re-doing it several times by (tokenization + token_to_ids).")
     parser.add_argument('--file_path', type=str, default='data/dump.txt',
                         help='The path to the data.')
-    parser.add_argument('--tokenizer_type', type=str, default='bert', choices=['bert', 'roberta'])
+    parser.add_argument('--tokenizer_type', type=str, default='bert', choices=['bert', 'roberta', 'gpt2'])
     parser.add_argument('--tokenizer_name', type=str, default='bert-base-uncased',
                         help="The tokenizer to use.")
     parser.add_argument('--dump_file', type=str, default='data/dump',
@@ -43,10 +43,16 @@ def main():
     logger.info(f'Loading Tokenizer ({args.tokenizer_name})')
     if args.tokenizer_type == 'bert':
         tokenizer = BertTokenizer.from_pretrained(args.tokenizer_name)
+        bos = tokenizer.special_tokens_map['cls_token'] # `[CLS]`
+        sep = tokenizer.special_tokens_map['sep_token'] # `[SEP]`
     elif args.tokenizer_type == 'roberta':
         tokenizer = RobertaTokenizer.from_pretrained(args.tokenizer_name)
-    bos = tokenizer.special_tokens_map['bos_token'] # `[CLS]` for bert, `<s>` for roberta
-    sep = tokenizer.special_tokens_map['sep_token'] # `[SEP]` for bert, `</s>` for roberta
+        bos = tokenizer.special_tokens_map['cls_token'] # `<s>`
+        sep = tokenizer.special_tokens_map['sep_token'] # `</s>`
+    elif args.tokenizer_type == 'gpt2':
+        tokenizer = GPT2Tokenizer.from_pretrained(args.tokenizer_name)
+        bos = tokenizer.special_tokens_map['bos_token'] # `<|endoftext|>`
+        sep = tokenizer.special_tokens_map['eos_token'] # `<|endoftext|>`    
 
     logger.info(f'Loading text from {args.file_path}')
     with open(args.file_path, 'r', encoding='utf8') as fp:

examples/distillation/scripts/extract.py

@@ -0,0 +1,89 @@
+# coding=utf-8
+# Copyright 2019-present, the HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Preprocessing script before training the distilled model.
+Specific to RoBERTa -> DistilRoBERTa and GPT2 -> DistilGPT2.
+"""
+from transformers import BertForMaskedLM, RobertaForMaskedLM, GPT2LMHeadModel
+import torch
+import argparse
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description="Extraction some layers of the full RobertaForMaskedLM or GPT2LMHeadModel for Transfer Learned Distillation")
+    parser.add_argument("--model_type", default="roberta", choices=["roberta", "gpt2"])
+    parser.add_argument("--model_name", default='roberta-large', type=str)
+    parser.add_argument("--dump_checkpoint", default='serialization_dir/tf_roberta_048131723.pth', type=str)
+    parser.add_argument("--vocab_transform", action='store_true')
+    args = parser.parse_args()
+
+
+    if args.model_type == 'roberta':
+        model = RobertaForMaskedLM.from_pretrained(args.model_name)
+        prefix = 'roberta'
+    elif args.model_type == 'gpt2':
+        model = GPT2LMHeadModel.from_pretrained(args.model_name)
+        prefix = 'transformer'
+
+    state_dict = model.state_dict()
+    compressed_sd = {}
+
+    ### Embeddings ###
+    if args.model_type == 'gpt2':
+        for param_name in ['wte.weight', 'wpe.weight']:
+            compressed_sd[f'{prefix}.{param_name}'] = state_dict[f'{prefix}.{param_name}']
+    else:
+        for w in ['word_embeddings', 'position_embeddings', 'token_type_embeddings']:
+            param_name = f'{prefix}.embeddings.{w}.weight'
+            compressed_sd[param_name] = state_dict[param_name]
+        for w in ['weight', 'bias']:
+            param_name = f'{prefix}.embeddings.LayerNorm.{w}'
+            compressed_sd[param_name] = state_dict[param_name]
+
+    ### Transformer Blocks ###
+    std_idx = 0
+    for teacher_idx in [0, 2, 4, 7, 9, 11]:
+        if args.model_type == 'gpt2':
+            for layer in ['ln_1', 'attn.c_attn', 'attn.c_proj', 'ln_2', 'mlp.c_fc', 'mlp.c_proj']:
+                for w in ['weight', 'bias']:
+                    compressed_sd[f'{prefix}.h.{std_idx}.{layer}.{w}'] = \
+                        state_dict[f'{prefix}.h.{teacher_idx}.{layer}.{w}']
+            compressed_sd[f'{prefix}.h.{std_idx}.attn.bias'] = state_dict[f'{prefix}.h.{teacher_idx}.attn.bias']
+        else:
+            for layer in ['attention.self.query', 'attention.self.key', 'attention.self.value',
+                        'attention.output.dense', 'attention.output.LayerNorm',
+                        'intermediate.dense', 'output.dense', 'output.LayerNorm']:
+                for w in ['weight', 'bias']:
+                    compressed_sd[f'{prefix}.encoder.layer.{std_idx}.{layer}.{w}'] = \
+                        state_dict[f'{prefix}.encoder.layer.{teacher_idx}.{layer}.{w}']
+        std_idx += 1
+
+    ### Language Modeling Head ###s
+    if args.model_type == 'roberta':
+        for layer in ['lm_head.decoder.weight', 'lm_head.bias']:
+            compressed_sd[f'{layer}'] = state_dict[f'{layer}']
+        if args.vocab_transform:
+            for w in ['weight', 'bias']:
+                compressed_sd[f'lm_head.dense.{w}'] = state_dict[f'lm_head.dense.{w}']
+                compressed_sd[f'lm_head.layer_norm.{w}'] = state_dict[f'lm_head.layer_norm.{w}']
+    elif args.model_type == 'gpt2':
+        for w in ['weight', 'bias']:
+            compressed_sd[f'{prefix}.ln_f.{w}'] = state_dict[f'{prefix}.ln_f.{w}']
+        compressed_sd[f'lm_head.weight'] = state_dict[f'lm_head.weight']
+
+    print(f'N layers selected for distillation: {std_idx}')
+    print(f'Number of params transfered for distillation: {len(compressed_sd.keys())}')
+
+    print(f'Save transfered checkpoint to {args.dump_checkpoint}.')
+    torch.save(compressed_sd, args.dump_checkpoint)

examples/distillation/scripts/extract_distilbert.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 """
 Preprocessing script before training DistilBERT.
+Specific to BERT -> DistilBERT.
 """
 from transformers import BertForMaskedLM, RobertaForMaskedLM
 import torch
@@ -21,7 +22,7 @@ import argparse
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser(description="Extraction some layers of the full BertForMaskedLM or RObertaForMaskedLM for Transfer Learned Distillation")
-    parser.add_argument("--model_type", default="bert", choices=["bert", "roberta"])
+    parser.add_argument("--model_type", default="bert", choices=["bert"])
     parser.add_argument("--model_name", default='bert-base-uncased', type=str)
     parser.add_argument("--dump_checkpoint", default='serialization_dir/tf_bert-base-uncased_0247911.pth', type=str)
     parser.add_argument("--vocab_transform", action='store_true')
@@ -31,9 +32,8 @@ if __name__ == '__main__':
     if args.model_type == 'bert':
         model = BertForMaskedLM.from_pretrained(args.model_name)
         prefix = 'bert'
-    elif args.model_type == 'roberta':
-        model = RobertaForMaskedLM.from_pretrained(args.model_name)
-        prefix = 'roberta'
+    else:
+        raise ValueError(f'args.model_type should be "bert".')
 
     state_dict = model.state_dict()
     compressed_sd = {}
@@ -68,20 +68,12 @@ if __name__ == '__main__':
                 state_dict[f'{prefix}.encoder.layer.{teacher_idx}.output.LayerNorm.{w}']
         std_idx += 1
 
-    if args.model_type == 'bert':
-        compressed_sd[f'vocab_projector.weight'] = state_dict[f'cls.predictions.decoder.weight']
-        compressed_sd[f'vocab_projector.bias'] = state_dict[f'cls.predictions.bias']
-        if args.vocab_transform:
-            for w in ['weight', 'bias']:
-                compressed_sd[f'vocab_transform.{w}'] = state_dict[f'cls.predictions.transform.dense.{w}']
-                compressed_sd[f'vocab_layer_norm.{w}'] = state_dict[f'cls.predictions.transform.LayerNorm.{w}']
-    elif args.model_type == 'roberta':
-        compressed_sd[f'vocab_projector.weight'] = state_dict[f'lm_head.decoder.weight']
-        compressed_sd[f'vocab_projector.bias'] = state_dict[f'lm_head.bias']
-        if args.vocab_transform:
-            for w in ['weight', 'bias']:
-                compressed_sd[f'vocab_transform.{w}'] = state_dict[f'lm_head.dense.{w}']
-                compressed_sd[f'vocab_layer_norm.{w}'] = state_dict[f'lm_head.layer_norm.{w}']
+    compressed_sd[f'vocab_projector.weight'] = state_dict[f'cls.predictions.decoder.weight']
+    compressed_sd[f'vocab_projector.bias'] = state_dict[f'cls.predictions.bias']
+    if args.vocab_transform:
+        for w in ['weight', 'bias']:
+            compressed_sd[f'vocab_transform.{w}'] = state_dict[f'cls.predictions.transform.dense.{w}']
+            compressed_sd[f'vocab_layer_norm.{w}'] = state_dict[f'cls.predictions.transform.LayerNorm.{w}']
 
     print(f'N layers selected for distillation: {std_idx}')
     print(f'Number of params transfered for distillation: {len(compressed_sd.keys())}')

examples/distillation/scripts/token_counts.py

@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """
-Preprocessing script before training DistilBERT.
+Preprocessing script before training the distilled model.
 """
 from collections import Counter
 import argparse

examples/distillation/train.py

@@ -13,7 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 """
-Training DistilBERT.
+Training the distilled model.
+Supported architectures include: BERT -> DistilBERT, RoBERTa -> DistilRoBERTa, GPT2 -> DistilGPT2.
 """
 import os
 import argparse
@@ -23,68 +24,96 @@ import shutil
 import numpy as np
 import torch
 
-from transformers import BertTokenizer, BertForMaskedLM, RobertaTokenizer, RobertaForMaskedLM
-from transformers import DistilBertForMaskedLM, DistilBertConfig
+from transformers import BertConfig, BertForMaskedLM, BertTokenizer
+from transformers import RobertaConfig, RobertaForMaskedLM, RobertaTokenizer
+from transformers import DistilBertConfig, DistilBertForMaskedLM, DistilBertTokenizer
+from transformers import GPT2Config, GPT2LMHeadModel, GPT2Tokenizer
 
 from distiller import Distiller
 from utils import git_log, logger, init_gpu_params, set_seed
-from dataset import Dataset
+from lm_seqs_dataset import LmSeqsDataset
 
 
+MODEL_CLASSES = {
+    'distilbert': (DistilBertConfig, DistilBertForMaskedLM, DistilBertTokenizer),
+    'roberta': (RobertaConfig, RobertaForMaskedLM, RobertaTokenizer),
+    'bert': (BertConfig, BertForMaskedLM, BertTokenizer),
+    'gpt2': (GPT2Config, GPT2LMHeadModel, GPT2Tokenizer)
+}
+
+def sanity_checks(args):
+    """
+    A bunch of args sanity checks to perform even starting...
+    """
+    assert (args.mlm and args.alpha_mlm > 0.) or (not args.mlm and args.alpha_mlm == 0.)
+    assert (args.alpha_mlm > 0. and args.alpha_clm == 0.) or (args.alpha_mlm == 0. and args.alpha_clm > 0.)
+    if args.mlm:
+        assert os.path.isfile(args.token_counts)
+        assert (args.student_type in ['roberta', 'distilbert']) and (args.teacher_type in ['roberta', 'bert'])
+    else:
+        assert (args.student_type in ['gpt2']) and (args.teacher_type in ['gpt2'])
+
+    assert args.teacher_type == args.student_type or (args.student_type=='distilbert' and args.teacher_type=='bert')
+    assert os.path.isfile(args.student_config)
+    if args.student_pretrained_weights is not None:
+        assert os.path.isfile(args.student_pretrained_weights)
+
+    if args.freeze_token_type_embds: assert args.student_type in ['roberta']
+
+    assert args.alpha_ce >= 0.
+    assert args.alpha_mlm >= 0.
+    assert args.alpha_clm >= 0.
+    assert args.alpha_mse >= 0.
+    assert args.alpha_cos >= 0.
+    assert args.alpha_ce + args.alpha_mlm + args.alpha_clm + args.alpha_mse + args.alpha_cos > 0.
+
+def freeze_pos_embeddings(student, args):
+    if args.student_type == 'roberta':
+        student.roberta.embeddings.position_embeddings.weight.requires_grad = False
+    elif args.student_type == 'gpt2':
+        student.transformer.wpe.weight.requires_grad = False
+
+def freeze_token_type_embeddings(student, args):
+    if args.student_type == 'roberta':
+        student.roberta.embeddings.token_type_embeddings.weight.requires_grad = False
+
 def main():
     parser = argparse.ArgumentParser(description="Training")
+    parser.add_argument("--force", action='store_true',
+                        help="Overwrite dump_path if it already exists.")
 
     parser.add_argument("--dump_path", type=str, required=True,
                         help="The output directory (log, checkpoints, parameters, etc.)")
     parser.add_argument("--data_file", type=str, required=True,
                         help="The binarized file (tokenized + tokens_to_ids) and grouped by sequence.")
-    parser.add_argument("--token_counts", type=str, required=True,
-                        help="The token counts in the data_file for MLM.")
-    parser.add_argument("--force", action='store_true',
-                        help="Overwrite dump_path if it already exists.")
 
-    parser.add_argument("--vocab_size", default=30522, type=int,
-                        help="The vocabulary size.")
-    parser.add_argument("--max_position_embeddings", default=512, type=int,
-                        help="Maximum sequence length we can model (including [CLS] and [SEP]).")
-    parser.add_argument("--sinusoidal_pos_embds", action='store_false',
-                        help="If true, the position embeddings are simply fixed with sinusoidal embeddings.")
-    parser.add_argument("--n_layers", default=6, type=int,
-                        help="Number of Transformer blocks.")
-    parser.add_argument("--n_heads", default=12, type=int,
-                        help="Number of heads in the self-attention module.")
-    parser.add_argument("--dim", default=768, type=int,
-                        help="Dimension through the network. Must be divisible by n_heads")
-    parser.add_argument("--hidden_dim", default=3072, type=int,
-                        help="Intermediate dimension in the FFN.")
-    parser.add_argument("--dropout", default=0.1, type=float,
-                        help="Dropout.")
-    parser.add_argument("--attention_dropout", default=0.1, type=float,
-                        help="Dropout in self-attention.")
-    parser.add_argument("--activation", default='gelu', type=str,
-                        help="Activation to use in self-attention")
-    parser.add_argument("--tie_weights_", action='store_false',
-                        help="If true, we tie the embeddings matrix with the projection over the vocabulary matrix. Default is true.")
-
-    parser.add_argument("--from_pretrained_weights", default=None, type=str,
+    parser.add_argument("--student_type", type=str, choices=["distilbert", "roberta", "gpt2"], required=True,
+                        help="The student type (DistilBERT, RoBERTa).")
+    parser.add_argument("--student_config", type=str, required=True,
+                        help="Path to the student configuration.")
+    parser.add_argument("--student_pretrained_weights", default=None, type=str,
                         help="Load student initialization checkpoint.")
-    parser.add_argument("--from_pretrained_config", default=None, type=str,
-                        help="Load student initialization architecture config.")
-    parser.add_argument("--teacher_type", default="bert", choices=["bert", "roberta"],
+
+    parser.add_argument("--teacher_type", choices=["bert", "roberta", "gpt2"], required=True,
                         help="Teacher type (BERT, RoBERTa).")
-    parser.add_argument("--teacher_name", default="bert-base-uncased", type=str,
+    parser.add_argument("--teacher_name", type=str, required=True,
                         help="The teacher model.")
 
     parser.add_argument("--temperature", default=2., type=float,
                         help="Temperature for the softmax temperature.")
     parser.add_argument("--alpha_ce", default=0.5, type=float,
                         help="Linear weight for the distillation loss. Must be >=0.")
-    parser.add_argument("--alpha_mlm", default=0.5, type=float,
-                        help="Linear weight for the MLM loss. Must be >=0.")
+    parser.add_argument("--alpha_mlm", default=0.0, type=float,
+                        help="Linear weight for the MLM loss. Must be >=0. Should be used in coonjunction with `mlm` flag.")
+    parser.add_argument("--alpha_clm", default=0.5, type=float,
+                        help="Linear weight for the CLM loss. Must be >=0.")
     parser.add_argument("--alpha_mse", default=0.0, type=float,
                         help="Linear weight of the MSE loss. Must be >=0.")
     parser.add_argument("--alpha_cos", default=0.0, type=float,
                         help="Linear weight of the cosine embedding loss. Must be >=0.")
+
+    parser.add_argument("--mlm", action="store_true",
+                        help="The LM step: MLM or CLM. If `mlm` is True, the MLM is used over CLM.")
     parser.add_argument("--mlm_mask_prop", default=0.15, type=float,
                         help="Proportion of tokens for which we need to make a prediction.")
     parser.add_argument("--word_mask", default=0.8, type=float,
@@ -95,17 +124,20 @@ def main():
                         help="Proportion of tokens to randomly replace.")
     parser.add_argument("--mlm_smoothing", default=0.7, type=float,
                         help="Smoothing parameter to emphasize more rare tokens (see XLM, similar to word2vec).")
+    parser.add_argument("--token_counts", type=str,
+                        help="The token counts in the data_file for MLM.")
+
     parser.add_argument("--restrict_ce_to_mask", action='store_true',
                         help="If true, compute the distilation loss only the [MLM] prediction distribution.")
+    parser.add_argument("--freeze_pos_embs", action="store_true",
+                        help="Freeze positional embeddings during distillation. For student_type in ['roberta', 'gpt2'] only.")
+    parser.add_argument("--freeze_token_type_embds", action="store_true",
+                        help="Freeze token type embeddings during distillation if existent. For student_type in ['roberta'] only.")
 
     parser.add_argument("--n_epoch", type=int, default=3,
                         help="Number of pass on the whole dataset.")
     parser.add_argument("--batch_size", type=int, default=5,
                         help="Batch size (for each process).")
-    parser.add_argument("--tokens_per_batch", type=int, default=-1,
-                        help="If specified, modify the batches so that they have approximately this number of tokens.")
-    parser.add_argument("--shuffle", action='store_false',
-                        help="If true, shuffle the sequence order. Default is true.")
     parser.add_argument("--group_by_size", action='store_false',
                         help="If true, group sequences that have similar length into the same batch. Default is true.")
 
@@ -141,6 +173,7 @@ def main():
     parser.add_argument("--checkpoint_interval", type=int, default=4000,
                         help="Checkpoint interval.")
     args = parser.parse_args()
+    sanity_checks(args)
 
 
     ## ARGS ##
@@ -164,21 +197,19 @@ def main():
         with open(os.path.join(args.dump_path, 'parameters.json'), 'w') as f:
             json.dump(vars(args), f, indent=4)
         git_log(args.dump_path)
-    assert (args.from_pretrained_weights is None and args.from_pretrained_config is None) or \
-           (args.from_pretrained_weights is not None and args.from_pretrained_config is not None)
 
+    student_config_class, student_model_class, _ = MODEL_CLASSES[args.student_type]
+    teacher_config_class, teacher_model_class, teacher_tokenizer_class = MODEL_CLASSES[args.teacher_type]
 
     ### TOKENIZER ###
-    if args.teacher_type == 'bert':
-        tokenizer = BertTokenizer.from_pretrained(args.teacher_name)
-    elif args.teacher_type == 'roberta':
-        tokenizer = RobertaTokenizer.from_pretrained(args.teacher_name)
+    tokenizer = teacher_tokenizer_class.from_pretrained(args.teacher_name)
     special_tok_ids = {}
     for tok_name, tok_symbol in tokenizer.special_tokens_map.items():
         idx = tokenizer.all_special_tokens.index(tok_symbol)
         special_tok_ids[tok_name] = tokenizer.all_special_ids[idx]
     logger.info(f'Special tokens {special_tok_ids}')
     args.special_tok_ids = special_tok_ids
+    args.max_model_input_size = tokenizer.max_model_input_sizes[args.teacher_name]
 
 
     ## DATA LOADER ##
@@ -187,35 +218,34 @@ def main():
         data = pickle.load(fp)
 
 
-    assert os.path.isfile(args.token_counts)
-    logger.info(f'Loading token counts from {args.token_counts} (already pre-computed)')
-    with open(args.token_counts, 'rb') as fp:
-        counts = pickle.load(fp)
-        assert len(counts) == args.vocab_size
-    token_probs = np.maximum(counts, 1) ** -args.mlm_smoothing
-    for idx in special_tok_ids.values():
-        token_probs[idx] = 0.  # do not predict special tokens
-    token_probs = torch.from_numpy(token_probs)
+    if args.mlm:
+        logger.info(f'Loading token counts from {args.token_counts} (already pre-computed)')
+        with open(args.token_counts, 'rb') as fp:
+            counts = pickle.load(fp)
+        
+        token_probs = np.maximum(counts, 1) ** -args.mlm_smoothing
+        for idx in special_tok_ids.values():
+            token_probs[idx] = 0.  # do not predict special tokens
+        token_probs = torch.from_numpy(token_probs)
+    else:
+        token_probs = None
 
 
-    train_dataloader = Dataset(params=args, data=data)
+    train_lm_seq_dataset = LmSeqsDataset(params=args, data=data)
     logger.info(f'Data loader created.')
 
 
     ## STUDENT ##
-    if args.from_pretrained_weights is not None:
-        assert os.path.isfile(args.from_pretrained_weights)
-        assert os.path.isfile(args.from_pretrained_config)
-        logger.info(f'Loading pretrained weights from {args.from_pretrained_weights}')
-        logger.info(f'Loading pretrained config from {args.from_pretrained_config}')
-        stu_architecture_config = DistilBertConfig.from_json_file(args.from_pretrained_config)
-        stu_architecture_config.output_hidden_states = True
-        student = DistilBertForMaskedLM.from_pretrained(args.from_pretrained_weights,
-                                                        config=stu_architecture_config)
+    logger.info(f'Loading student config from {args.student_config}')
+    stu_architecture_config = student_config_class.from_pretrained(args.student_config)
+    stu_architecture_config.output_hidden_states = True
+
+    if args.student_pretrained_weights is not None:
+        logger.info(f'Loading pretrained weights from {args.student_pretrained_weights}')
+        student = student_model_class.from_pretrained(args.student_pretrained_weights,
+                                                      config=stu_architecture_config)
     else:
-        args.vocab_size_or_config_json_file = args.vocab_size
-        stu_architecture_config = DistilBertConfig(**vars(args), output_hidden_states=True)
-        student = DistilBertForMaskedLM(stu_architecture_config)
+        student = student_model_class(stu_architecture_config)
 
 
     if args.n_gpu > 0:
@@ -224,18 +254,31 @@ def main():
 
 
     ## TEACHER ##
-    if args.teacher_type == 'bert':
-        teacher = BertForMaskedLM.from_pretrained(args.teacher_name, output_hidden_states=True)
-    elif args.teacher_type == 'roberta':
-        teacher = RobertaForMaskedLM.from_pretrained(args.teacher_name, output_hidden_states=True)
+    teacher = teacher_model_class.from_pretrained(args.teacher_name, output_hidden_states=True)
     if args.n_gpu > 0:
         teacher.to(f'cuda:{args.local_rank}')
     logger.info(f'Teacher loaded from {args.teacher_name}.')
 
+
+    ## FREEZING ##
+    if args.freeze_pos_embs:
+        freeze_pos_embeddings(student, args)
+    if args.freeze_token_type_embds:
+        freeze_token_type_embeddings(student, args)
+
+
+    ## SANITY CHECKS ##
+    assert student.config.vocab_size == teacher.config.vocab_size
+    assert student.config.hidden_size == teacher.config.hidden_size
+    assert student.config.max_position_embeddings == teacher.config.max_position_embeddings
+    if args.mlm:
+        assert token_probs.size(0) == stu_architecture_config.vocab_size
+
+
     ## DISTILLER ##
     torch.cuda.empty_cache()
     distiller = Distiller(params=args,
-                          dataloader=train_dataloader,
+                          dataset=train_lm_seq_dataset,
                           token_probs=token_probs,
                           student=student,
                           teacher=teacher)

examples/distillation/training_configs/distilbert-base-uncased.json

@@ -0,0 +1,15 @@
+{
+	"activation": "gelu",
+	"attention_dropout": 0.1,
+	"dim": 768,
+	"dropout": 0.1,
+	"hidden_dim": 3072,
+	"initializer_range": 0.02,
+	"max_position_embeddings": 512,
+	"n_heads": 12,
+	"n_layers": 6,
+	"sinusoidal_pos_embds": true,
+	"tie_weights_": true,
+	"vocab_size": 30522
+  }
+  

examples/distillation/training_configs/distilgpt2.json

@@ -0,0 +1,10 @@
+{
+	"initializer_range": 0.02,
+	"layer_norm_epsilon": 0.00001,
+	"n_ctx": 1024,
+	"n_embd": 768,
+	"n_head": 12,
+	"n_layer": 6,
+	"n_positions": 1024,
+	"vocab_size": 50257
+}

examples/run_generation.py

@@ -14,7 +14,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" Conditional text generation with the auto-regressive models of the library (GPT/GPT-2/Transformer-XL/XLNet)
+""" Conditional text generation with the auto-regressive models of the library (GPT/GPT-2/CTRL/Transformer-XL/XLNet)
 """
 from __future__ import absolute_import, division, print_function, unicode_literals
 
@@ -26,12 +26,14 @@ import torch
 import torch.nn.functional as F
 import numpy as np
 
-from transformers import GPT2Config, OpenAIGPTConfig, XLNetConfig, TransfoXLConfig
+from transformers import GPT2Config, OpenAIGPTConfig, XLNetConfig, TransfoXLConfig, XLMConfig, CTRLConfig
 
 from transformers import GPT2LMHeadModel, GPT2Tokenizer
 from transformers import OpenAIGPTLMHeadModel, OpenAIGPTTokenizer
 from transformers import XLNetLMHeadModel, XLNetTokenizer
 from transformers import TransfoXLLMHeadModel, TransfoXLTokenizer
+from transformers import CTRLLMHeadModel, CTRLTokenizer
+from transformers import XLMWithLMHeadModel, XLMTokenizer
 
 
 logging.basicConfig(format = '%(asctime)s - %(levelname)s - %(name)s -   %(message)s',
@@ -41,13 +43,15 @@ logger = logging.getLogger(__name__)
 
 MAX_LENGTH = int(10000)  # Hardcoded max length to avoid infinite loop
 
-ALL_MODELS = sum((tuple(conf.pretrained_config_archive_map.keys()) for conf in (GPT2Config, OpenAIGPTConfig, XLNetConfig, TransfoXLConfig)), ())
+ALL_MODELS = sum((tuple(conf.pretrained_config_archive_map.keys()) for conf in (GPT2Config, OpenAIGPTConfig, XLNetConfig, TransfoXLConfig, XLMConfig, CTRLConfig)), ())
 
 MODEL_CLASSES = {
     'gpt2': (GPT2LMHeadModel, GPT2Tokenizer),
+    'ctrl': (CTRLLMHeadModel, CTRLTokenizer),
     'openai-gpt': (OpenAIGPTLMHeadModel, OpenAIGPTTokenizer),
     'xlnet': (XLNetLMHeadModel, XLNetTokenizer),
     'transfo-xl': (TransfoXLLMHeadModel, TransfoXLTokenizer),
+    'xlm': (XLMWithLMHeadModel, XLMTokenizer),
 }
 
 # Padding text to help Transformer-XL and XLNet with short prompts as proposed by Aman Rusia
@@ -103,7 +107,7 @@ def top_k_top_p_filtering(logits, top_k=0, top_p=0.0, filter_value=-float('Inf')
     return logits
 
 
-def sample_sequence(model, length, context, num_samples=1, temperature=1, top_k=0, top_p=0.0, is_xlnet=False, device='cpu'):
+def sample_sequence(model, length, context, num_samples=1, temperature=1, top_k=0, top_p=0.0, repetition_penalty=1.0, is_xlnet=False, xlm_lang=None, device='cpu'):
     context = torch.tensor(context, dtype=torch.long, device=device)
     context = context.unsqueeze(0).repeat(num_samples, 1)
     generated = context
@@ -121,10 +125,21 @@ def sample_sequence(model, length, context, num_samples=1, temperature=1, top_k=
                 target_mapping[0, 0, -1] = 1.0  # predict last token
                 inputs = {'input_ids': input_ids, 'perm_mask': perm_mask, 'target_mapping': target_mapping}
 
+            if xlm_lang is not None:
+                inputs["langs"] = torch.tensor([xlm_lang] * inputs["input_ids"].shape[1], device=device).view(1, -1)
+
             outputs = model(**inputs)  # Note: we could also use 'past' with GPT-2/Transfo-XL/XLNet (cached hidden-states)
-            next_token_logits = outputs[0][0, -1, :] / temperature
+            next_token_logits = outputs[0][0, -1, :] / (temperature if temperature > 0 else 1.)
+
+            # reptition penalty from CTRL (https://arxiv.org/abs/1909.05858)
+            for _ in set(generated):
+                next_token_logits[_] /= repetition_penalty
+                
             filtered_logits = top_k_top_p_filtering(next_token_logits, top_k=top_k, top_p=top_p)
-            next_token = torch.multinomial(F.softmax(filtered_logits, dim=-1), num_samples=1)
+            if temperature == 0: #greedy sampling:
+                next_token = torch.argmax(filtered_logits).unsqueeze(0)
+            else:
+                next_token = torch.multinomial(F.softmax(filtered_logits, dim=-1), num_samples=1)
             generated = torch.cat((generated, next_token.unsqueeze(0)), dim=1)
     return generated
 
@@ -137,16 +152,25 @@ def main():
                         help="Path to pre-trained model or shortcut name selected in the list: " + ", ".join(ALL_MODELS))
     parser.add_argument("--prompt", type=str, default="")
     parser.add_argument("--padding_text", type=str, default="")
+    parser.add_argument("--xlm_lang", type=str, default="", help="Optional language when used with the XLM model.")
     parser.add_argument("--length", type=int, default=20)
-    parser.add_argument("--temperature", type=float, default=1.0)
+    parser.add_argument("--temperature", type=float, default=1.0,
+                        help="temperature of 0 implies greedy sampling")
+    parser.add_argument("--repetition_penalty", type=float, default=1.0,
+                        help="primarily useful for CTRL model; in that case, use 1.2")
     parser.add_argument("--top_k", type=int, default=0)
     parser.add_argument("--top_p", type=float, default=0.9)
     parser.add_argument("--no_cuda", action='store_true',
                         help="Avoid using CUDA when available")
     parser.add_argument('--seed', type=int, default=42,
                         help="random seed for initialization")
+    parser.add_argument('--stop_token', type=str, default=None,
+                        help="Token at which text generation is stopped")
     args = parser.parse_args()
-
+    if args.model_type in ["ctrl"]:
+        if args.temperature > 0.7 : 
+            print('CTRL typically works better with lower temperatures (and lower top_k).')
+        
     args.device = torch.device("cuda" if torch.cuda.is_available() and not args.no_cuda else "cpu")
     args.n_gpu = torch.cuda.device_count()
 
@@ -168,6 +192,18 @@ def main():
 
     print(args)
     while True:
+        xlm_lang = None
+        # XLM Language usage detailed in the issues #1414
+        if args.model_type in ["xlm"] and hasattr(tokenizer, 'lang2id') and hasattr(model.config, 'use_lang_emb') \
+                and model.config.use_lang_emb:
+            if args.xlm_lang:
+                language = args.xlm_lang
+            else:
+                language = None
+                while language not in tokenizer.lang2id.keys():
+                    language = input("Using XLM. Select language in " + str(list(tokenizer.lang2id.keys())) + " >>> ")
+            xlm_lang = tokenizer.lang2id[language]
+
         raw_text = args.prompt if args.prompt else input("Model prompt >>> ")
         if args.model_type in ["transfo-xl", "xlnet"]:
             # Models with memory likes to have a long prompt for short inputs.
@@ -180,11 +216,16 @@ def main():
             temperature=args.temperature,
             top_k=args.top_k,
             top_p=args.top_p,
-            device=args.device,
+            repetition_penalty=args.repetition_penalty,
             is_xlnet=bool(args.model_type == "xlnet"),
+            xlm_lang=xlm_lang,
+            device=args.device,
         )
         out = out[0, len(context_tokens):].tolist()
-        text = tokenizer.decode(out, clean_up_tokenization_spaces=True)
+
+        text = tokenizer.decode(out, clean_up_tokenization_spaces=True, skip_special_tokens=True)
+        text = text[: text.find(args.stop_token) if args.stop_token else None]
+
         print(text)
         if args.prompt:
             break

examples/run_glue.py

@@ -53,7 +53,8 @@ from transformers import glue_convert_examples_to_features as convert_examples_t
 
 logger = logging.getLogger(__name__)
 
-ALL_MODELS = sum((tuple(conf.pretrained_config_archive_map.keys()) for conf in (BertConfig, XLNetConfig, XLMConfig, RobertaConfig)), ())
+ALL_MODELS = sum((tuple(conf.pretrained_config_archive_map.keys()) for conf in (BertConfig, XLNetConfig, XLMConfig, 
+                                                                                RobertaConfig, DistilBertConfig)), ())
 
 MODEL_CLASSES = {
     'bert': (BertConfig, BertForSequenceClassification, BertTokenizer),
@@ -134,8 +135,9 @@ def train(args, train_dataset, model, tokenizer):
             batch = tuple(t.to(args.device) for t in batch)
             inputs = {'input_ids':      batch[0],
                       'attention_mask': batch[1],
-                      'token_type_ids': batch[2] if args.model_type in ['bert', 'xlnet'] else None,  # XLM, DistilBERT and RoBERTa don't use segment_ids
                       'labels':         batch[3]}
+            if args.model_type != 'distilbert':
+                inputs['token_type_ids'] = batch[2] if args.model_type in ['bert', 'xlnet'] else None  # XLM, DistilBERT and RoBERTa don't use segment_ids
             outputs = model(**inputs)
             loss = outputs[0]  # model outputs are always tuple in transformers (see doc)
 
@@ -224,8 +226,9 @@ def evaluate(args, model, tokenizer, prefix=""):
             with torch.no_grad():
                 inputs = {'input_ids':      batch[0],
                           'attention_mask': batch[1],
-                          'token_type_ids': batch[2] if args.model_type in ['bert', 'xlnet'] else None,  # XLM, DistilBERT and RoBERTa don't use segment_ids
                           'labels':         batch[3]}
+                if args.model_type != 'distilbert':
+                    inputs['token_type_ids'] = batch[2] if args.model_type in ['bert', 'xlnet'] else None  # XLM, DistilBERT and RoBERTa don't use segment_ids
                 outputs = model(**inputs)
                 tmp_eval_loss, logits = outputs[:2]
 
@@ -246,7 +249,7 @@ def evaluate(args, model, tokenizer, prefix=""):
         result = compute_metrics(eval_task, preds, out_label_ids)
         results.update(result)
 
-        output_eval_file = os.path.join(eval_output_dir, "eval_results.txt")
+        output_eval_file = os.path.join(eval_output_dir, prefix, "eval_results.txt")
         with open(output_eval_file, "w") as writer:
             logger.info("***** Eval results {} *****".format(prefix))
             for key in sorted(result.keys()):
@@ -268,7 +271,7 @@ def load_and_cache_examples(args, task, tokenizer, evaluate=False):
         list(filter(None, args.model_name_or_path.split('/'))).pop(),
         str(args.max_seq_length),
         str(task)))
-    if os.path.exists(cached_features_file):
+    if os.path.exists(cached_features_file) and not args.overwrite_cache:
         logger.info("Loading features from cached file %s", cached_features_file)
         features = torch.load(cached_features_file)
     else:
@@ -487,9 +490,11 @@ def main():
         logger.info("Evaluate the following checkpoints: %s", checkpoints)
         for checkpoint in checkpoints:
             global_step = checkpoint.split('-')[-1] if len(checkpoints) > 1 else ""
+            prefix = checkpoint.split('/')[-1] if checkpoint.find('checkpoint') != -1 else ""
+            
             model = model_class.from_pretrained(checkpoint)
             model.to(args.device)
-            result = evaluate(args, model, tokenizer, prefix=global_step)
+            result = evaluate(args, model, tokenizer, prefix=prefix)
             result = dict((k + '_{}'.format(global_step), v) for k, v in result.items())
             results.update(result)
 

examples/run_lm_finetuning.py

@@ -27,6 +27,8 @@ import logging
 import os
 import pickle
 import random
+import re
+import shutil
 
 import numpy as np
 import torch
@@ -59,7 +61,7 @@ class TextDataset(Dataset):
     def __init__(self, tokenizer, file_path='train', block_size=512):
         assert os.path.isfile(file_path)
         directory, filename = os.path.split(file_path)
-        cached_features_file = os.path.join(directory, f'cached_lm_{block_size}_{filename}')
+        cached_features_file = os.path.join(directory, 'cached_lm_' + block_size + '_' + filename)
 
         if os.path.exists(cached_features_file):
             logger.info("Loading features from cached file %s", cached_features_file)
@@ -74,9 +76,8 @@ class TextDataset(Dataset):
 
             tokenized_text = tokenizer.convert_tokens_to_ids(tokenizer.tokenize(text))
 
-            while len(tokenized_text) >= block_size:  # Truncate in block of block_size
-                self.examples.append(tokenizer.add_special_tokens_single_sequence(tokenized_text[:block_size]))
-                tokenized_text = tokenized_text[block_size:]
+            for i in range(0, len(tokenized_text)-block_size+1, block_size): # Truncate in block of block_size
+                self.examples.append(tokenizer.build_inputs_with_special_tokens(tokenized_text[i:i+block_size]))
             # Note that we are loosing the last truncated example here for the sake of simplicity (no padding)
             # If your dataset is small, first you should loook for a bigger one :-) and second you
             # can change this behavior by adding (model specific) padding.
@@ -105,11 +106,43 @@ def set_seed(args):
         torch.cuda.manual_seed_all(args.seed)
 
 
+def _rotate_checkpoints(args, checkpoint_prefix, use_mtime=False):
+    if not args.save_total_limit:
+        return
+    if args.save_total_limit <= 0:
+        return
+
+    # Check if we should delete older checkpoint(s)
+    glob_checkpoints = glob.glob(os.path.join(args.output_dir, '{}-*'.format(checkpoint_prefix)))
+    if len(glob_checkpoints) <= args.save_total_limit:
+        return
+
+    ordering_and_checkpoint_path = []
+    for path in glob_checkpoints:
+        if use_mtime:
+            ordering_and_checkpoint_path.append((os.path.getmtime(path), path))
+        else:
+            regex_match = re.match('.*{}-([0-9]+)'.format(checkpoint_prefix), path)
+            if regex_match and regex_match.groups():
+                ordering_and_checkpoint_path.append((int(regex_match.groups()[0]), path))
+
+    checkpoints_sorted = sorted(ordering_and_checkpoint_path)
+    checkpoints_sorted = [checkpoint[1] for checkpoint in checkpoints_sorted]
+    number_of_checkpoints_to_delete = max(0, len(checkpoints_sorted) - args.save_total_limit)
+    checkpoints_to_be_deleted = checkpoints_sorted[:number_of_checkpoints_to_delete]
+    for checkpoint in checkpoints_to_be_deleted:
+        logger.info("Deleting older checkpoint [{}] due to args.save_total_limit".format(checkpoint))
+        shutil.rmtree(checkpoint)
+
+
 def mask_tokens(inputs, tokenizer, args):
     """ Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. """
     labels = inputs.clone()
     # We sample a few tokens in each sequence for masked-LM training (with probability args.mlm_probability defaults to 0.15 in Bert/RoBERTa)
-    masked_indices = torch.bernoulli(torch.full(labels.shape, args.mlm_probability)).bool()
+    probability_matrix = torch.full(labels.shape, args.mlm_probability)
+    special_tokens_mask = [tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True) for val in labels.tolist()]
+    probability_matrix.masked_fill_(torch.tensor(special_tokens_mask, dtype=torch.bool), value=0.0)
+    masked_indices = torch.bernoulli(probability_matrix).bool()
     labels[~masked_indices] = -1  # We only compute loss on masked tokens
 
     # 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
@@ -223,8 +256,9 @@ def train(args, train_dataset, model, tokenizer):
                     logging_loss = tr_loss
 
                 if args.local_rank in [-1, 0] and args.save_steps > 0 and global_step % args.save_steps == 0:
+                    checkpoint_prefix = 'checkpoint'
                     # Save model checkpoint
-                    output_dir = os.path.join(args.output_dir, 'checkpoint-{}'.format(global_step))
+                    output_dir = os.path.join(args.output_dir, '{}-{}'.format(checkpoint_prefix, global_step))
                     if not os.path.exists(output_dir):
                         os.makedirs(output_dir)
                     model_to_save = model.module if hasattr(model, 'module') else model  # Take care of distributed/parallel training
@@ -232,6 +266,8 @@ def train(args, train_dataset, model, tokenizer):
                     torch.save(args, os.path.join(output_dir, 'training_args.bin'))
                     logger.info("Saving model checkpoint to %s", output_dir)
 
+                    _rotate_checkpoints(args, checkpoint_prefix)
+
             if args.max_steps > 0 and global_step > args.max_steps:
                 epoch_iterator.close()
                 break
@@ -283,7 +319,7 @@ def evaluate(args, model, tokenizer, prefix=""):
         "perplexity": perplexity
     }
 
-    output_eval_file = os.path.join(eval_output_dir, "eval_results.txt")
+    output_eval_file = os.path.join(eval_output_dir, prefix, "eval_results.txt")
     with open(output_eval_file, "w") as writer:
         logger.info("***** Eval results {} *****".format(prefix))
         for key in sorted(result.keys()):
@@ -360,6 +396,8 @@ def main():
                         help="Log every X updates steps.")
     parser.add_argument('--save_steps', type=int, default=50,
                         help="Save checkpoint every X updates steps.")
+    parser.add_argument('--save_total_limit', type=int, default=None,
+                        help='Limit the total amount of checkpoints, delete the older checkpoints in the output_dir, does not delete by default')
     parser.add_argument("--eval_all_checkpoints", action='store_true',
                         help="Evaluate all checkpoints starting with the same prefix as model_name_or_path ending and ending with step number")
     parser.add_argument("--no_cuda", action='store_true',
@@ -485,9 +523,11 @@ def main():
         logger.info("Evaluate the following checkpoints: %s", checkpoints)
         for checkpoint in checkpoints:
             global_step = checkpoint.split('-')[-1] if len(checkpoints) > 1 else ""
+            prefix = checkpoint.split('/')[-1] if checkpoint.find('checkpoint') != -1 else ""
+            
             model = model_class.from_pretrained(checkpoint)
             model.to(args.device)
-            result = evaluate(args, model, tokenizer, prefix=global_step)
+            result = evaluate(args, model, tokenizer, prefix=prefix)
             result = dict((k + '_{}'.format(global_step), v) for k, v in result.items())
             results.update(result)
 

examples/run_multiple_choice.py

@@ -293,7 +293,7 @@ def load_and_cache_examples(args, task, tokenizer, evaluate=False, test=False):
         list(filter(None, args.model_name_or_path.split('/'))).pop(),
         str(args.max_seq_length),
         str(task)))
-    if os.path.exists(cached_features_file):
+    if os.path.exists(cached_features_file) and not args.overwrite_cache:
         logger.info("Loading features from cached file %s", cached_features_file)
         features = torch.load(cached_features_file)
     else:
@@ -306,14 +306,14 @@ def load_and_cache_examples(args, task, tokenizer, evaluate=False, test=False):
         else:
             examples = processor.get_train_examples(args.data_dir)
         logger.info("Training number: %s", str(len(examples)))
-        features = convert_examples_to_features(examples, label_list, args.max_seq_length, tokenizer,
-            cls_token_at_end=bool(args.model_type in ['xlnet']),            # xlnet has a cls token at the end
-            cls_token=tokenizer.cls_token,
-            sep_token=tokenizer.sep_token,
-            sep_token_extra=bool(args.model_type in ['roberta']),
-            cls_token_segment_id=2 if args.model_type in ['xlnet'] else 0,
+        features = convert_examples_to_features(
+            examples,
+            label_list,
+            args.max_seq_length,
+            tokenizer,
             pad_on_left=bool(args.model_type in ['xlnet']),                 # pad on the left for xlnet
-            pad_token_segment_id=4 if args.model_type in ['xlnet'] else 0)
+            pad_token_segment_id=4 if args.model_type in ['xlnet'] else 0
+        )
         if args.local_rank in [-1, 0]:
             logger.info("Saving features into cached file %s", cached_features_file)
             torch.save(features, cached_features_file)
@@ -362,7 +362,7 @@ def main():
                         help="Whether to run eval on the dev set.")
     parser.add_argument("--do_test", action='store_true', help='Whether to run test on the test set')
     parser.add_argument("--evaluate_during_training", action='store_true',
-                        help="Rul evaluation during training at each logging step.")
+                        help="Run evaluation during training at each logging step.")
     parser.add_argument("--do_lower_case", action='store_true',
                         help="Set this flag if you are using an uncased model.")
 
@@ -512,9 +512,11 @@ def main():
         logger.info("Evaluate the following checkpoints: %s", checkpoints)
         for checkpoint in checkpoints:
             global_step = checkpoint.split('-')[-1] if len(checkpoints) > 1 else ""
+            prefix = checkpoint.split('/')[-1] if checkpoint.find('checkpoint') != -1 else ""
+            
             model = model_class.from_pretrained(checkpoint)
             model.to(args.device)
-            result = evaluate(args, model, tokenizer, prefix=global_step)
+            result = evaluate(args, model, tokenizer, prefix=prefix)
             result = dict((k + '_{}'.format(global_step), v) for k, v in result.items())
             results.update(result)
 
@@ -528,9 +530,11 @@ def main():
         logger.info("Evaluate the following checkpoints: %s", checkpoints)
         for checkpoint in checkpoints:
             global_step = checkpoint.split('-')[-1] if len(checkpoints) > 1 else ""
+            prefix = checkpoint.split('/')[-1] if checkpoint.find('checkpoint') != -1 else ""
+            
             model = model_class.from_pretrained(checkpoint)
             model.to(args.device)
-            result = evaluate(args, model, tokenizer, prefix=global_step, test=True)
+            result = evaluate(args, model, tokenizer, prefix=prefix, test=True)
             result = dict((k + '_{}'.format(global_step), v) for k, v in result.items())
             results.update(result)
     if best_steps:

examples/run_squad.py

@@ -13,7 +13,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" Finetuning the library models for question-answering on SQuAD (Bert, XLM, XLNet)."""
+""" Finetuning the library models for question-answering on SQuAD (DistilBERT, Bert, XLM, XLNet)."""
 
 from __future__ import absolute_import, division, print_function
 
@@ -135,9 +135,10 @@ def train(args, train_dataset, model, tokenizer):
             batch = tuple(t.to(args.device) for t in batch)
             inputs = {'input_ids':       batch[0],
                       'attention_mask':  batch[1], 
-                      'token_type_ids':  None if args.model_type == 'xlm' else batch[2],  
                       'start_positions': batch[3], 
                       'end_positions':   batch[4]}
+            if args.model_type != 'distilbert':
+                inputs['token_type_ids'] = None if args.model_type == 'xlm' else batch[2]
             if args.model_type in ['xlnet', 'xlm']:
                 inputs.update({'cls_index': batch[5],
                                'p_mask':       batch[6]})
@@ -218,9 +219,10 @@ def evaluate(args, model, tokenizer, prefix=""):
         batch = tuple(t.to(args.device) for t in batch)
         with torch.no_grad():
             inputs = {'input_ids':      batch[0],
-                      'attention_mask': batch[1],
-                      'token_type_ids': None if args.model_type == 'xlm' else batch[2]  # XLM don't use segment_ids
+                      'attention_mask': batch[1]
                       }
+            if args.model_type != 'distilbert':
+                inputs['token_type_ids'] = None if args.model_type == 'xlm' else batch[2]  # XLM don't use segment_ids
             example_indices = batch[3]
             if args.model_type in ['xlnet', 'xlm']:
                 inputs.update({'cls_index': batch[4],

examples/run_tf_glue.py

@@ -1,6 +1,6 @@
 import tensorflow as tf
 import tensorflow_datasets
-from transformers import *
+from transformers import BertTokenizer, TFBertForSequenceClassification, glue_convert_examples_to_features, BertForSequenceClassification
 
 # Load dataset, tokenizer, model from pretrained model/vocabulary
 tokenizer = BertTokenizer.from_pretrained('bert-base-cased')
@@ -23,12 +23,6 @@ model.compile(optimizer=optimizer, loss=loss, metrics=[metric])
 history = model.fit(train_dataset, epochs=2, steps_per_epoch=115,
                     validation_data=valid_dataset, validation_steps=7)
 
->>> Train for 115 steps, validate for 7 steps
->>> Epoch 1/2
->>> 115/115 [==============================] - 53s 459ms/step - loss: 0.6033 - accuracy: 0.6712 - val_loss: 0.4964 - val_accuracy: 0.7647
->>> Epoch 2/2
->>> 115/115 [==============================] - 33s 289ms/step - loss: 0.4141 - accuracy: 0.8160 - val_loss: 0.3914 - val_accuracy: 0.8382
-
 # Load the TensorFlow model in PyTorch for inspection
 model.save_pretrained('./save/')
 pytorch_model = BertForSequenceClassification.from_pretrained('./save/', from_tf=True)
@@ -44,5 +38,3 @@ pred_1 = pytorch_model(**inputs_1)[0].argmax().item()
 pred_2 = pytorch_model(**inputs_2)[0].argmax().item()
 print("sentence_1 is", "a paraphrase" if pred_1 else "not a paraphrase", "of sentence_0")
 print("sentence_2 is", "a paraphrase" if pred_2 else "not a paraphrase", "of sentence_0")
->>> sentence_1 is a paraphrase of sentence_0
->>> sentence_2 is not a paraphrase of sentence_0

examples/utils_multiple_choice.py

@@ -13,7 +13,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-""" BERT multiple choice fine-tuning: utilities to work with multiple choice tasks of reading comprehension  """
+""" Multiple choice fine-tuning: utilities to work with multiple choice tasks of reading comprehension  """
 
 from __future__ import absolute_import, division, print_function
 
@@ -26,6 +26,8 @@ import json
 import csv
 import glob
 import tqdm
+from typing import List
+from transformers import PreTrainedTokenizer
 
 
 logger = logging.getLogger(__name__)
@@ -34,13 +36,13 @@ logger = logging.getLogger(__name__)
 class InputExample(object):
     """A single training/test example for multiple choice"""
 
-    def __init__(self, example_id, question,  contexts, endings, label=None):
+    def __init__(self, example_id, question, contexts, endings, label=None):
         """Constructs a InputExample.
 
         Args:
             example_id: Unique id for the example.
             contexts: list of str. The untokenized text of the first sequence (context of corresponding question).
-            question: string. The untokenized text of the second sequence (qustion).
+            question: string. The untokenized text of the second sequence (question).
             endings: list of str. multiple choice's options. Its length must be equal to contexts' length.
             label: (Optional) string. The label of the example. This should be
             specified for train and dev examples, but not for test examples.
@@ -66,7 +68,7 @@ class InputFeatures(object):
                 'input_mask': input_mask,
                 'segment_ids': segment_ids
             }
-            for _, input_ids, input_mask, segment_ids in choices_features
+            for input_ids, input_mask, segment_ids in choices_features
         ]
         self.label = label
 
@@ -192,7 +194,7 @@ class SwagProcessor(DataProcessor):
             return lines
 
 
-    def _create_examples(self, lines, type):
+    def _create_examples(self, lines: List[List[str]], type: str):
         """Creates examples for the training and dev sets."""
         if type == "train" and lines[0][-1] != 'label':
             raise ValueError(
@@ -300,24 +302,18 @@ class ArcProcessor(DataProcessor):
         return examples
 
 
-def convert_examples_to_features(examples, label_list, max_seq_length,
-                                 tokenizer,
-                                 cls_token_at_end=False,
-                                 cls_token='[CLS]',
-                                 cls_token_segment_id=1,
-                                 sep_token='[SEP]',
-                                 sequence_a_segment_id=0,
-                                 sequence_b_segment_id=1,
-                                 sep_token_extra=False,
-                                 pad_token_segment_id=0,
-                                 pad_on_left=False,
-                                 pad_token=0,
-                                 mask_padding_with_zero=True):
-    """ Loads a data file into a list of `InputBatch`s
-        `cls_token_at_end` define the location of the CLS token:
-            - False (Default, BERT/XLM pattern): [CLS] + A + [SEP] + B + [SEP]
-            - True (XLNet/GPT pattern): A + [SEP] + B + [SEP] + [CLS]
-        `cls_token_segment_id` define the segment id associated to the CLS token (0 for BERT, 2 for XLNet)
+def convert_examples_to_features(
+    examples: List[InputExample],
+    label_list: List[str],
+    max_length: int,
+    tokenizer: PreTrainedTokenizer,
+    pad_token_segment_id=0,
+    pad_on_left=False,
+    pad_token=0,
+    mask_padding_with_zero=True,
+) -> List[InputFeatures]:
+    """
+    Loads a data file into a list of `InputFeatures`
     """
 
     label_map = {label : i for i, label in enumerate(label_list)}
@@ -328,125 +324,70 @@ def convert_examples_to_features(examples, label_list, max_seq_length,
             logger.info("Writing example %d of %d" % (ex_index, len(examples)))
         choices_features = []
         for ending_idx, (context, ending) in enumerate(zip(example.contexts, example.endings)):
-            tokens_a = tokenizer.tokenize(context)
-            tokens_b = None
+            text_a = context
             if example.question.find("_") != -1:
-                #this is for cloze question
-                tokens_b = tokenizer.tokenize(example.question.replace("_", ending))
+                # this is for cloze question
+                text_b = example.question.replace("_", ending)
             else:
-                tokens_b = tokenizer.tokenize(example.question + " " + ending)
-                # you can add seq token between quesiotn and ending. This does not make too much difference.
-                # tokens_b = tokenizer.tokenize(example.question)
-                # tokens_b += [sep_token]
-                # if sep_token_extra:
-                #     tokens_b += [sep_token]
-                # tokens_b += tokenizer.tokenize(ending)
+                text_b = example.question + " " + ending
 
-            special_tokens_count = 4 if sep_token_extra else 3
-            _truncate_seq_pair(tokens_a, tokens_b, max_seq_length - special_tokens_count)
+            inputs = tokenizer.encode_plus(
+                text_a,
+                text_b,
+                add_special_tokens=True,
+                max_length=max_length,
+            )
+            if 'num_truncated_tokens' in inputs and inputs['num_truncated_tokens'] > 0:
+                logger.info('Attention! you are cropping tokens (swag task is ok). '
+                        'If you are training ARC and RACE and you are poping question + options,'
+                        'you need to try to use a bigger max seq length!')
 
-            # The convention in BERT is:
-            # (a) For sequence pairs:
-            #  tokens:   [CLS] is this jack ##son ##ville ? [SEP] no it is not . [SEP]
-            #  type_ids:   0   0  0    0    0     0       0   0   1  1  1  1   1   1
-            # (b) For single sequences:
-            #  tokens:   [CLS] the dog is hairy . [SEP]
-            #  type_ids:   0   0   0   0  0     0   0
-            #
-            # Where "type_ids" are used to indicate whether this is the first
-            # sequence or the second sequence. The embedding vectors for `type=0` and
-            # `type=1` were learned during pre-training and are added to the wordpiece
-            # embedding vector (and position vector). This is not *strictly* necessary
-            # since the [SEP] token unambiguously separates the sequences, but it makes
-            # it easier for the model to learn the concept of sequences.
-            #
-            # For classification tasks, the first vector (corresponding to [CLS]) is
-            # used as as the "sentence vector". Note that this only makes sense because
-            # the entire model is fine-tuned.
-            tokens = tokens_a + [sep_token]
-            if sep_token_extra:
-                # roberta uses an extra separator b/w pairs of sentences
-                tokens += [sep_token]
-
-            segment_ids = [sequence_a_segment_id] * len(tokens)
-
-            if tokens_b:
-                tokens += tokens_b + [sep_token]
-                segment_ids += [sequence_b_segment_id] * (len(tokens_b) + 1)
-
-            if cls_token_at_end:
-                tokens = tokens + [cls_token]
-                segment_ids = segment_ids + [cls_token_segment_id]
-            else:
-                tokens = [cls_token] + tokens
-                segment_ids = [cls_token_segment_id] + segment_ids
-
-            input_ids = tokenizer.convert_tokens_to_ids(tokens)
+            input_ids, token_type_ids = inputs["input_ids"], inputs["token_type_ids"]
 
             # The mask has 1 for real tokens and 0 for padding tokens. Only real
             # tokens are attended to.
-            input_mask = [1 if mask_padding_with_zero else 0] * len(input_ids)
+            attention_mask = [1 if mask_padding_with_zero else 0] * len(input_ids)
 
             # Zero-pad up to the sequence length.
-            padding_length = max_seq_length - len(input_ids)
+            padding_length = max_length - len(input_ids)
             if pad_on_left:
                 input_ids = ([pad_token] * padding_length) + input_ids
-                input_mask = ([0 if mask_padding_with_zero else 1] * padding_length) + input_mask
-                segment_ids = ([pad_token_segment_id] * padding_length) + segment_ids
+                attention_mask = ([0 if mask_padding_with_zero else 1] * padding_length) + attention_mask
+                token_type_ids = ([pad_token_segment_id] * padding_length) + token_type_ids
             else:
                 input_ids = input_ids + ([pad_token] * padding_length)
-                input_mask = input_mask + ([0 if mask_padding_with_zero else 1] * padding_length)
-                segment_ids = segment_ids + ([pad_token_segment_id] * padding_length)
+                attention_mask = attention_mask + ([0 if mask_padding_with_zero else 1] * padding_length)
+                token_type_ids = token_type_ids + ([pad_token_segment_id] * padding_length)
+
+            assert len(input_ids) == max_length
+            assert len(attention_mask) == max_length
+            assert len(token_type_ids) == max_length
+            choices_features.append((input_ids, attention_mask, token_type_ids))
+
 
-            assert len(input_ids) == max_seq_length
-            assert len(input_mask) == max_seq_length
-            assert len(segment_ids) == max_seq_length
-            choices_features.append((tokens, input_ids, input_mask, segment_ids))
         label = label_map[example.label]
 
         if ex_index < 2:
             logger.info("*** Example ***")
             logger.info("race_id: {}".format(example.example_id))
-            for choice_idx, (tokens, input_ids, input_mask, segment_ids) in enumerate(choices_features):
+            for choice_idx, (input_ids, attention_mask, token_type_ids) in enumerate(choices_features):
                 logger.info("choice: {}".format(choice_idx))
-                logger.info("tokens: {}".format(' '.join(tokens)))
                 logger.info("input_ids: {}".format(' '.join(map(str, input_ids))))
-                logger.info("input_mask: {}".format(' '.join(map(str, input_mask))))
-                logger.info("segment_ids: {}".format(' '.join(map(str, segment_ids))))
+                logger.info("attention_mask: {}".format(' '.join(map(str, attention_mask))))
+                logger.info("token_type_ids: {}".format(' '.join(map(str, token_type_ids))))
                 logger.info("label: {}".format(label))
 
         features.append(
             InputFeatures(
-                example_id = example.example_id,
-                choices_features = choices_features,
-                label = label
+                example_id=example.example_id,
+                choices_features=choices_features,
+                label=label,
             )
         )
 
     return features
 
 
-def _truncate_seq_pair(tokens_a, tokens_b, max_length):
-    """Truncates a sequence pair in place to the maximum length."""
-
-    # This is a simple heuristic which will always truncate the longer sequence
-    # one token at a time. This makes more sense than truncating an equal percent
-    # of tokens from each, since if one sequence is very short then each token
-    # that's truncated likely contains more information than a longer sequence.
-
-    # However, since we'd better not to remove tokens of options and questions, you can choose to use a bigger
-    # length or only pop from context
-    while True:
-        total_length = len(tokens_a) + len(tokens_b)
-        if total_length <= max_length:
-            break
-        if len(tokens_a) > len(tokens_b):
-            tokens_a.pop()
-        else:
-            logger.info('Attention! you are removing from token_b (swag task is ok). '
-                        'If you are training ARC and RACE (you are poping question + options), '
-                        'you need to try to use a bigger max seq length!')
-            tokens_b.pop()
 
 
 processors = {
@@ -456,7 +397,7 @@ processors = {
 }
 
 
-GLUE_TASKS_NUM_LABELS = {
+MULTIPLE_CHOICE_TASKS_NUM_LABELS = {
     "race", 4,
     "swag", 4,
     "arc", 4

requirements-dev.txt

@@ -0,0 +1,48 @@
+absl-py==0.8.0
+astor==0.8.0
+atomicwrites==1.3.0
+attrs==19.2.0
+boto3==1.9.243
+botocore==1.12.243
+certifi==2019.9.11
+chardet==3.0.4
+Click==7.0
+docutils==0.15.2
+gast==0.2.2
+google-pasta==0.1.7
+grpcio==1.24.1
+h5py==2.10.0
+idna==2.8
+importlib-metadata==0.23
+jmespath==0.9.4
+joblib==0.14.0
+Keras-Applications==1.0.8
+Keras-Preprocessing==1.1.0
+Markdown==3.1.1
+more-itertools==7.2.0
+numpy==1.17.2
+opt-einsum==3.1.0
+packaging==19.2
+pluggy==0.13.0
+protobuf==3.10.0
+py==1.8.0
+pyparsing==2.4.2
+pytest==5.2.1
+python-dateutil==2.8.0
+regex==2019.8.19
+requests==2.22.0
+s3transfer==0.2.1
+sacremoses==0.0.35
+sentencepiece==0.1.83
+six==1.12.0
+tensorboard==2.0.0
+tensorflow==2.0.0
+tensorflow-estimator==2.0.0
+termcolor==1.1.0
+torch==1.2.0
+tqdm==4.36.1
+urllib3==1.25.6
+wcwidth==0.1.7
+Werkzeug==0.16.0
+wrapt==1.11.2
+zipp==0.6.0

setup.py

@@ -3,7 +3,7 @@ Simple check list from AllenNLP repo: https://github.com/allenai/allennlp/blob/m
 
 To create the package for pypi.
 
-1. Change the version in __init__.py and setup.py.
+1. Change the version in __init__.py, setup.py as well as docs/source/conf.py.
 
 2. Commit these changes with the message: "Release: VERSION"
 
@@ -38,13 +38,13 @@ from setuptools import find_packages, setup
 
 setup(
     name="transformers",
-    version="2.0.0",
-    author="Thomas Wolf, Lysandre Debut, Victor Sanh, Julien Chaumond, Google AI Language Team Authors, Open AI team Authors",
+    version="2.1.0",
+    author="Thomas Wolf, Lysandre Debut, Victor Sanh, Julien Chaumond, Google AI Language Team Authors, Open AI team Authors, Facebook AI Authors, Carnegie Mellon University Authors",
     author_email="thomas@huggingface.co",
-    description="Repository of pre-trained NLP Transformer models: BERT & RoBERTa, GPT & GPT-2, Transformer-XL, XLNet and XLM",
+    description="State-of-the-art Natural Language Processing for TensorFlow 2.0 and PyTorch",
     long_description=open("README.md", "r", encoding='utf-8').read(),
     long_description_content_type="text/markdown",
-    keywords='NLP deep learning transformer pytorch BERT GPT GPT-2 google openai CMU',
+    keywords='NLP deep learning transformer pytorch tensorflow BERT GPT GPT-2 google openai CMU',
     license='Apache',
     url="https://github.com/huggingface/transformers",
     packages=find_packages(exclude=["*.tests", "*.tests.*",

transformers/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "2.0.0"
+__version__ = "2.1.0"
 
 # Work around to update TensorFlow's absl.logging threshold which alters the
 # default Python logging output behavior when present.
@@ -37,6 +37,7 @@ from .tokenization_bert import BertTokenizer, BasicTokenizer, WordpieceTokenizer
 from .tokenization_openai import OpenAIGPTTokenizer
 from .tokenization_transfo_xl import (TransfoXLTokenizer, TransfoXLCorpus)
 from .tokenization_gpt2 import GPT2Tokenizer
+from .tokenization_ctrl import CTRLTokenizer
 from .tokenization_xlnet import XLNetTokenizer, SPIECE_UNDERLINE
 from .tokenization_xlm import XLMTokenizer
 from .tokenization_roberta import RobertaTokenizer
@@ -49,7 +50,9 @@ from .configuration_bert import BertConfig, BERT_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_openai import OpenAIGPTConfig, OPENAI_GPT_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_transfo_xl import TransfoXLConfig, TRANSFO_XL_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_gpt2 import GPT2Config, GPT2_PRETRAINED_CONFIG_ARCHIVE_MAP
+from .configuration_ctrl import CTRLConfig, CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_xlnet import XLNetConfig, XLNET_PRETRAINED_CONFIG_ARCHIVE_MAP
+from .configuration_ctrl import CTRLConfig, CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_xlm import XLMConfig, XLM_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_roberta import RobertaConfig, ROBERTA_PRETRAINED_CONFIG_ARCHIVE_MAP
 from .configuration_distilbert import DistilBertConfig, DISTILBERT_PRETRAINED_CONFIG_ARCHIVE_MAP
@@ -73,15 +76,19 @@ if is_torch_available():
     from .modeling_gpt2 import (GPT2PreTrainedModel, GPT2Model,
                                 GPT2LMHeadModel, GPT2DoubleHeadsModel,
                                 load_tf_weights_in_gpt2, GPT2_PRETRAINED_MODEL_ARCHIVE_MAP)
+    from .modeling_ctrl import (CTRLPreTrainedModel, CTRLModel,
+                                CTRLLMHeadModel,
+                                CTRL_PRETRAINED_MODEL_ARCHIVE_MAP)
     from .modeling_xlnet import (XLNetPreTrainedModel, XLNetModel, XLNetLMHeadModel,
-                                XLNetForSequenceClassification, XLNetForQuestionAnsweringSimple,
-                                XLNetForQuestionAnswering,
+                                XLNetForSequenceClassification, XLNetForMultipleChoice,
+                                XLNetForQuestionAnsweringSimple, XLNetForQuestionAnswering,
                                 load_tf_weights_in_xlnet, XLNET_PRETRAINED_MODEL_ARCHIVE_MAP)
     from .modeling_xlm import (XLMPreTrainedModel , XLMModel,
                             XLMWithLMHeadModel, XLMForSequenceClassification,
                             XLMForQuestionAnswering, XLMForQuestionAnsweringSimple,
                             XLM_PRETRAINED_MODEL_ARCHIVE_MAP)
-    from .modeling_roberta import (RobertaForMaskedLM, RobertaModel, RobertaForSequenceClassification,
+    from .modeling_roberta import (RobertaForMaskedLM, RobertaModel,
+                                RobertaForSequenceClassification, RobertaForMultipleChoice,
                                 ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP)
     from .modeling_distilbert import (DistilBertForMaskedLM, DistilBertModel,
                                 DistilBertForSequenceClassification, DistilBertForQuestionAnswering,
@@ -148,6 +155,11 @@ if is_tf_available():
                                          load_distilbert_pt_weights_in_tf2,
                                          TF_DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP)
 
+    from .modeling_tf_ctrl import (TFCTRLPreTrainedModel, TFCTRLModel,
+                                    TFCTRLLMHeadModel,
+                                    load_ctrl_pt_weights_in_tf2,
+                                    TF_CTRL_PRETRAINED_MODEL_ARCHIVE_MAP)
+
 # TF 2.0 <=> PyTorch conversion utilities
 if is_tf_available() and is_torch_available():
     from .modeling_tf_pytorch_utils import (convert_tf_weight_name_to_pt_weight_name,

transformers/configuration_auto.py

@@ -26,6 +26,7 @@ from .configuration_xlnet import XLNetConfig
 from .configuration_xlm import XLMConfig
 from .configuration_roberta import RobertaConfig
 from .configuration_distilbert import DistilBertConfig
+from .configuration_ctrl import CTRLConfig
 
 logger = logging.getLogger(__name__)
 
@@ -49,7 +50,7 @@ class AutoConfig(object):
             - contains `xlnet`: XLNetConfig (XLNet model)
             - contains `xlm`: XLMConfig (XLM model)
             - contains `roberta`: RobertaConfig (RoBERTa model)
-
+            - contains `ctrl` : CTRLConfig (CTRL model)
         This class cannot be instantiated using `__init__()` (throw an error).
     """
     def __init__(self):
@@ -71,7 +72,7 @@ class AutoConfig(object):
             - contains `xlnet`: XLNetConfig (XLNet model)
             - contains `xlm`: XLMConfig (XLM model)
             - contains `roberta`: RobertaConfig (RoBERTa model)
-
+            - contains `ctrl` : CTRLConfig (CTRL model)
         Params:
             pretrained_model_name_or_path: either:
 
@@ -129,7 +130,8 @@ class AutoConfig(object):
             return XLNetConfig.from_pretrained(pretrained_model_name_or_path, **kwargs)
         elif 'xlm' in pretrained_model_name_or_path:
             return XLMConfig.from_pretrained(pretrained_model_name_or_path, **kwargs)
-
+        elif 'ctrl' in pretrained_model_name_or_path:
+            return CTRLConfig.from_pretrained(pretrained_model_name_or_path, **kwargs)
         raise ValueError("Unrecognized model identifier in {}. Should contains one of "
                          "'bert', 'openai-gpt', 'gpt2', 'transfo-xl', 'xlnet', "
-                         "'xlm', 'roberta'".format(pretrained_model_name_or_path))
+                         "'xlm', 'roberta', 'ctrl'".format(pretrained_model_name_or_path))

transformers/configuration_ctrl.py

@@ -0,0 +1,143 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and HuggingFace Inc. team.
+# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" Salesforce CTRL configuration """
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import json
+import logging
+import sys
+from io import open
+
+from .configuration_utils import PretrainedConfig
+
+logger = logging.getLogger(__name__)
+
+CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP = {"ctrl": "https://storage.googleapis.com/sf-ctrl/pytorch/ctrl-config.json"}
+
+class CTRLConfig(PretrainedConfig):
+    """Configuration class to store the configuration of a `CTRLModel`.
+
+    Args:
+        vocab_size_or_config_json_file: Vocabulary size of `inputs_ids` in `CTRLModel` or a configuration json file.
+        n_positions: Number of positional embeddings.
+        n_ctx: Size of the causal mask (usually same as n_positions).
+        dff: Size of the inner dimension of the FFN.
+        n_embd: Dimensionality of the embeddings and hidden states.
+        n_layer: Number of hidden layers in the Transformer encoder.
+        n_head: Number of attention heads for each attention layer in
+            the Transformer encoder.
+        layer_norm_epsilon: epsilon to use in the layer norm layers
+        resid_pdrop: The dropout probabilitiy for all fully connected
+            layers in the embeddings, encoder, and pooler.
+        attn_pdrop: The dropout ratio for the attention
+            probabilities.
+        embd_pdrop: The dropout ratio for the embeddings.
+        initializer_range: The sttdev of the truncated_normal_initializer for
+            initializing all weight matrices.
+    """
+    pretrained_config_archive_map = CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP
+
+    def __init__(
+        self,
+        vocab_size_or_config_json_file=246534,
+        n_positions=256,
+        n_ctx=256,
+        n_embd=1280,
+        dff=8192,
+        n_layer=48,
+        n_head=16,
+        resid_pdrop=0.1,
+        embd_pdrop=0.1,
+        attn_pdrop=0.1,
+        layer_norm_epsilon=1e-6,
+        initializer_range=0.02,
+
+        num_labels=1,
+        summary_type='cls_index',
+        summary_use_proj=True,
+        summary_activation=None,
+        summary_proj_to_labels=True,
+        summary_first_dropout=0.1,
+        **kwargs
+    ):
+        """Constructs CTRLConfig.
+
+        Args:
+            vocab_size_or_config_json_file: Vocabulary size of `inputs_ids` in `CTRLModel` or a configuration json file.
+            n_positions: Number of positional embeddings.
+            n_ctx: Size of the causal mask (usually same as n_positions).
+            dff: Size of the inner dimension of the FFN.
+            n_embd: Dimensionality of the embeddings and hidden states.
+            n_layer: Number of hidden layers in the Transformer encoder.
+            n_head: Number of attention heads for each attention layer in
+                the Transformer encoder.
+            layer_norm_epsilon: epsilon to use in the layer norm layers
+            resid_pdrop: The dropout probabilitiy for all fully connected
+                layers in the embeddings, encoder, and pooler.
+            attn_pdrop: The dropout ratio for the attention
+                probabilities.
+            embd_pdrop: The dropout ratio for the embeddings.
+            initializer_range: The sttdev of the truncated_normal_initializer for
+                initializing all weight matrices.
+        """
+        super(CTRLConfig, self).__init__(**kwargs)
+
+        self.vocab_size = vocab_size_or_config_json_file if isinstance(vocab_size_or_config_json_file, int) else -1
+        self.n_ctx = n_ctx
+        self.n_positions = n_positions
+        self.n_embd = n_embd
+        self.n_layer = n_layer
+        self.n_head = n_head
+        self.dff = dff
+        self.resid_pdrop = resid_pdrop
+        self.embd_pdrop = embd_pdrop
+        self.attn_pdrop = attn_pdrop
+        self.layer_norm_epsilon = layer_norm_epsilon
+        self.initializer_range = initializer_range
+
+        self.num_labels = num_labels
+        self.summary_type = summary_type
+        self.summary_use_proj = summary_use_proj
+        self.summary_activation = summary_activation
+        self.summary_first_dropout = summary_first_dropout
+        self.summary_proj_to_labels = summary_proj_to_labels
+        if isinstance(vocab_size_or_config_json_file, str) or (sys.version_info[0] == 2
+                        and isinstance(vocab_size_or_config_json_file, unicode)):
+            with open(vocab_size_or_config_json_file, "r", encoding="utf-8") as reader:
+                json_config = json.loads(reader.read())
+            for key, value in json_config.items():
+                self.__dict__[key] = value
+        elif not isinstance(vocab_size_or_config_json_file, int):
+            raise ValueError(
+                "First argument must be either a vocabulary size (int)"
+                "or the path to a pretrained model config file (str)"
+            )
+
+    @property
+    def max_position_embeddings(self):
+        return self.n_positions
+
+    @property
+    def hidden_size(self):
+        return self.n_embd
+
+    @property
+    def num_attention_heads(self):
+        return self.n_head
+
+    @property
+    def num_hidden_layers(self):
+        return self.n_layer

transformers/configuration_gpt2.py

@@ -28,7 +28,8 @@ logger = logging.getLogger(__name__)
 
 GPT2_PRETRAINED_CONFIG_ARCHIVE_MAP = {"gpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-config.json",
                                       "gpt2-medium": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-medium-config.json",
-                                      "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-config.json"}
+                                      "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-config.json",
+                                      "distilgpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/distilgpt2-config.json",}
 
 class GPT2Config(PretrainedConfig):
     """Configuration class to store the configuration of a `GPT2Model`.

transformers/convert_pytorch_checkpoint_to_tf2.py

@@ -31,7 +31,8 @@ from transformers import (BertConfig, TFBertForPreTraining, TFBertForQuestionAns
                                   TransfoXLConfig, TFTransfoXLLMHeadModel, load_transfo_xl_pt_weights_in_tf2, TRANSFO_XL_PRETRAINED_CONFIG_ARCHIVE_MAP,
                                   OpenAIGPTConfig, TFOpenAIGPTLMHeadModel, load_openai_gpt_pt_weights_in_tf2, OPENAI_GPT_PRETRAINED_CONFIG_ARCHIVE_MAP,
                                   RobertaConfig, TFRobertaForMaskedLM, TFRobertaForSequenceClassification, load_roberta_pt_weights_in_tf2, ROBERTA_PRETRAINED_CONFIG_ARCHIVE_MAP,
-                                  DistilBertConfig, TFDistilBertForMaskedLM, TFDistilBertForQuestionAnswering, load_distilbert_pt_weights_in_tf2, DISTILBERT_PRETRAINED_CONFIG_ARCHIVE_MAP)
+                                  DistilBertConfig, TFDistilBertForMaskedLM, TFDistilBertForQuestionAnswering, load_distilbert_pt_weights_in_tf2, DISTILBERT_PRETRAINED_CONFIG_ARCHIVE_MAP,
+                                  CTRLConfig, TFCTRLLMHeadModel, load_ctrl_pt_weights_in_tf2, CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP)
 
 if is_torch_available():
     import torch
@@ -43,7 +44,8 @@ if is_torch_available():
                                       TransfoXLLMHeadModel, TRANSFO_XL_PRETRAINED_MODEL_ARCHIVE_MAP,
                                       OpenAIGPTLMHeadModel, OPENAI_GPT_PRETRAINED_MODEL_ARCHIVE_MAP,
                                       RobertaForMaskedLM, RobertaForSequenceClassification, ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
-                                      DistilBertForMaskedLM, DistilBertForQuestionAnswering, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP)
+                                      DistilBertForMaskedLM, DistilBertForQuestionAnswering, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP,
+                                      CTRLLMHeadModel, CTRL_PRETRAINED_MODEL_ARCHIVE_MAP)
 else:
     (BertForPreTraining, BertForQuestionAnswering, BertForSequenceClassification, BERT_PRETRAINED_MODEL_ARCHIVE_MAP,
     GPT2LMHeadModel, GPT2_PRETRAINED_MODEL_ARCHIVE_MAP,
@@ -52,7 +54,8 @@ else:
     TransfoXLLMHeadModel, TRANSFO_XL_PRETRAINED_MODEL_ARCHIVE_MAP,
     OpenAIGPTLMHeadModel, OPENAI_GPT_PRETRAINED_MODEL_ARCHIVE_MAP,
     RobertaForMaskedLM, RobertaForSequenceClassification, ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP,
-    DistilBertForMaskedLM, DistilBertForQuestionAnswering, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP,) = (
+    DistilBertForMaskedLM, DistilBertForQuestionAnswering, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP,
+    CTRLLMHeadModel, CTRL_PRETRAINED_MODEL_ARCHIVE_MAP) = (
         None, None, None, None,
         None, None,
         None, None,
@@ -60,7 +63,8 @@ else:
         None, None,
         None, None,
         None, None, None,
-        None, None, None,)
+        None, None, None,
+        None, None)
 
 
 import logging
@@ -80,6 +84,7 @@ MODEL_CLASSES = {
     'roberta-large-mnli': (RobertaConfig, TFRobertaForSequenceClassification, load_roberta_pt_weights_in_tf2, RobertaForSequenceClassification, ROBERTA_PRETRAINED_MODEL_ARCHIVE_MAP, ROBERTA_PRETRAINED_CONFIG_ARCHIVE_MAP),
     'distilbert': (DistilBertConfig, TFDistilBertForMaskedLM, load_distilbert_pt_weights_in_tf2, DistilBertForMaskedLM, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP, DISTILBERT_PRETRAINED_CONFIG_ARCHIVE_MAP),
     'distilbert-base-uncased-distilled-squad': (DistilBertConfig, TFDistilBertForQuestionAnswering, load_distilbert_pt_weights_in_tf2, DistilBertForQuestionAnswering, DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP, DISTILBERT_PRETRAINED_CONFIG_ARCHIVE_MAP),
+    'ctrl': (CTRLConfig, TFCTRLLMHeadModel, load_ctrl_pt_weights_in_tf2, CTRLLMHeadModel, CTRL_PRETRAINED_MODEL_ARCHIVE_MAP, CTRL_PRETRAINED_CONFIG_ARCHIVE_MAP)
 }
 
 def convert_pt_checkpoint_to_tf(model_type, pytorch_checkpoint_path, config_file, tf_dump_path, compare_with_pt_model=False, use_cached_models=True):
@@ -173,10 +178,12 @@ def convert_all_pt_checkpoints_to_tf(args_model_type, tf_dump_path, model_shortc
             else:
                 model_file = cached_path(model_shortcut_name, force_download=not use_cached_models)
 
-            convert_pt_checkpoint_to_tf(model_type,
-                                        model_file,
-                                        config_file,
-                                        os.path.join(tf_dump_path, model_shortcut_name + '-tf_model.h5'),
+            if os.path.isfile(model_shortcut_name):
+                model_shortcut_name = 'converted_model'
+            convert_pt_checkpoint_to_tf(model_type=model_type,
+                                        pytorch_checkpoint_path=model_file,
+                                        config_file=config_file,
+                                        tf_dump_path=os.path.join(tf_dump_path, model_shortcut_name + '-tf_model.h5'),
                                         compare_with_pt_model=compare_with_pt_model)
             os.remove(config_file)
             os.remove(model_file)
@@ -228,6 +235,7 @@ if __name__ == "__main__":
     convert_all_pt_checkpoints_to_tf(args.model_type.lower() if args.model_type is not None else None,
                                         args.tf_dump_path,
                                         model_shortcut_names_or_path=[args.pytorch_checkpoint_path] if args.pytorch_checkpoint_path is not None else None,
+                                        config_shortcut_names_or_path=[args.config_file] if args.config_file is not None else None,
                                         compare_with_pt_model=args.compare_with_pt_model,
                                         use_cached_models=args.use_cached_models,
                                         only_convert_finetuned_models=args.only_convert_finetuned_models)

transformers/data/processors/glue.py

@@ -79,17 +79,13 @@ def glue_convert_examples_to_features(examples, tokenizer,
         if ex_index % 10000 == 0:
             logger.info("Writing example %d" % (ex_index))
         if is_tf_dataset:
-            example = InputExample(example['idx'].numpy(),
-                                   example['sentence1'].numpy().decode('utf-8'),
-                                   example['sentence2'].numpy().decode('utf-8'),
-                                   str(example['label'].numpy()))
+            example = processor.get_example_from_tensor_dict(example)
 
         inputs = tokenizer.encode_plus(
             example.text_a,
             example.text_b,
             add_special_tokens=True,
             max_length=max_length,
-            truncate_first_sequence=True  # We're truncating the first sequence in priority
         )
         input_ids, token_type_ids = inputs["input_ids"], inputs["token_type_ids"]
 
@@ -157,6 +153,13 @@ def glue_convert_examples_to_features(examples, tokenizer,
 class MrpcProcessor(DataProcessor):
     """Processor for the MRPC data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence1'].numpy().decode('utf-8'),
+                            tensor_dict['sentence2'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         logger.info("LOOKING AT {}".format(os.path.join(data_dir, "train.tsv")))
@@ -190,6 +193,13 @@ class MrpcProcessor(DataProcessor):
 class MnliProcessor(DataProcessor):
     """Processor for the MultiNLI data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['premise'].numpy().decode('utf-8'),
+                            tensor_dict['hypothesis'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -233,6 +243,13 @@ class MnliMismatchedProcessor(MnliProcessor):
 class ColaProcessor(DataProcessor):
     """Processor for the CoLA data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence'].numpy().decode('utf-8'),
+                            None,
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -262,6 +279,13 @@ class ColaProcessor(DataProcessor):
 class Sst2Processor(DataProcessor):
     """Processor for the SST-2 data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence'].numpy().decode('utf-8'),
+                            None,
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -293,6 +317,13 @@ class Sst2Processor(DataProcessor):
 class StsbProcessor(DataProcessor):
     """Processor for the STS-B data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence1'].numpy().decode('utf-8'),
+                            tensor_dict['sentence2'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -325,6 +356,13 @@ class StsbProcessor(DataProcessor):
 class QqpProcessor(DataProcessor):
     """Processor for the QQP data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['question1'].numpy().decode('utf-8'),
+                            tensor_dict['question2'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -360,6 +398,13 @@ class QqpProcessor(DataProcessor):
 class QnliProcessor(DataProcessor):
     """Processor for the QNLI data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['question'].numpy().decode('utf-8'),
+                            tensor_dict['sentence'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -393,6 +438,13 @@ class QnliProcessor(DataProcessor):
 class RteProcessor(DataProcessor):
     """Processor for the RTE data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence1'].numpy().decode('utf-8'),
+                            tensor_dict['sentence2'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(
@@ -425,6 +477,13 @@ class RteProcessor(DataProcessor):
 class WnliProcessor(DataProcessor):
     """Processor for the WNLI data set (GLUE version)."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """See base class."""
+        return InputExample(tensor_dict['idx'].numpy(),
+                            tensor_dict['sentence1'].numpy().decode('utf-8'),
+                            tensor_dict['sentence2'].numpy().decode('utf-8'),
+                            str(tensor_dict['label'].numpy()))
+
     def get_train_examples(self, data_dir):
         """See base class."""
         return self._create_examples(

transformers/data/processors/utils.py

@@ -86,6 +86,15 @@ class InputFeatures(object):
 class DataProcessor(object):
     """Base class for data converters for sequence classification data sets."""
 
+    def get_example_from_tensor_dict(self, tensor_dict):
+        """Gets an example from a dict with tensorflow tensors
+
+        Args:
+            tensor_dict: Keys and values should match the corresponding Glue
+                tensorflow_dataset examples.
+        """
+        raise NotImplementedError()
+
     def get_train_examples(self, data_dir):
         """Gets a collection of `InputExample`s for the train set."""
         raise NotImplementedError()

transformers/file_utils.py

@@ -27,7 +27,7 @@ logger = logging.getLogger(__name__)  # pylint: disable=invalid-name
 
 try:
     import tensorflow as tf
-    assert int(tf.__version__[0]) >= 2
+    assert hasattr(tf, '__version__') and int(tf.__version__[0]) >= 2
     _tf_available = True  # pylint: disable=invalid-name
     logger.info("TensorFlow version {} available.".format(tf.__version__))
 except (ImportError, AssertionError):

transformers/modeling_auto.py

@@ -21,6 +21,7 @@ import logging
 from .modeling_bert import BertModel, BertForMaskedLM, BertForSequenceClassification, BertForQuestionAnswering
 from .modeling_openai import OpenAIGPTModel, OpenAIGPTLMHeadModel
 from .modeling_gpt2 import GPT2Model, GPT2LMHeadModel
+from .modeling_ctrl import CTRLModel, CTRLLMHeadModel
 from .modeling_transfo_xl import TransfoXLModel, TransfoXLLMHeadModel
 from .modeling_xlnet import XLNetModel, XLNetLMHeadModel, XLNetForSequenceClassification, XLNetForQuestionAnswering
 from .modeling_xlm import XLMModel, XLMWithLMHeadModel, XLMForSequenceClassification, XLMForQuestionAnswering
@@ -51,6 +52,7 @@ class AutoModel(object):
             - contains `bert`: BertModel (Bert model)
             - contains `openai-gpt`: OpenAIGPTModel (OpenAI GPT model)
             - contains `gpt2`: GPT2Model (OpenAI GPT-2 model)
+            - contains `ctrl`: CTRLModel (Salesforce CTRL  model)
             - contains `transfo-xl`: TransfoXLModel (Transformer-XL model)
             - contains `xlnet`: XLNetModel (XLNet model)
             - contains `xlm`: XLMModel (XLM model)
@@ -73,6 +75,7 @@ class AutoModel(object):
             - contains `bert`: BertModel (Bert model)
             - contains `openai-gpt`: OpenAIGPTModel (OpenAI GPT model)
             - contains `gpt2`: GPT2Model (OpenAI GPT-2 model)
+            - contains `ctrl`: CTRLModel (Salesforce CTRL  model)
             - contains `transfo-xl`: TransfoXLModel (Transformer-XL model)
             - contains `xlnet`: XLNetModel (XLNet model)
             - contains `xlm`: XLMModel (XLM model)
@@ -149,10 +152,11 @@ class AutoModel(object):
             return XLNetModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
         elif 'xlm' in pretrained_model_name_or_path:
             return XLMModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
-
+        elif 'ctrl' in pretrained_model_name_or_path:
+            return CTRLModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
         raise ValueError("Unrecognized model identifier in {}. Should contains one of "
                          "'bert', 'openai-gpt', 'gpt2', 'transfo-xl', 'xlnet', "
-                         "'xlm', 'roberta'".format(pretrained_model_name_or_path))
+                         "'xlm', 'roberta, 'ctrl'".format(pretrained_model_name_or_path))
 
 
 class AutoModelWithLMHead(object):
@@ -172,6 +176,7 @@ class AutoModelWithLMHead(object):
             - contains `bert`: BertForMaskedLM (Bert model)
             - contains `openai-gpt`: OpenAIGPTLMHeadModel (OpenAI GPT model)
             - contains `gpt2`: GPT2LMHeadModel (OpenAI GPT-2 model)
+            - contains `ctrl`: CTRLLMModel (Salesforce CTRL model)
             - contains `transfo-xl`: TransfoXLLMHeadModel (Transformer-XL model)
             - contains `xlnet`: XLNetLMHeadModel (XLNet model)
             - contains `xlm`: XLMWithLMHeadModel (XLM model)
@@ -273,10 +278,11 @@ class AutoModelWithLMHead(object):
             return XLNetLMHeadModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
         elif 'xlm' in pretrained_model_name_or_path:
             return XLMWithLMHeadModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
-
+        elif 'ctrl' in pretrained_model_name_or_path:
+            return CTRLLMHeadModel.from_pretrained(pretrained_model_name_or_path, *model_args, **kwargs)
         raise ValueError("Unrecognized model identifier in {}. Should contains one of "
                          "'bert', 'openai-gpt', 'gpt2', 'transfo-xl', 'xlnet', "
-                         "'xlm', 'roberta'".format(pretrained_model_name_or_path))
+                         "'xlm', 'roberta','ctrl'".format(pretrained_model_name_or_path))
 
 
 class AutoModelForSequenceClassification(object):

transformers/modeling_bert.py

@@ -118,7 +118,7 @@ def load_tf_weights_in_bert(model, config, tf_checkpoint_path):
 
 
 def gelu(x):
-    """ Original Implementation of the gelu activation function in Google Bert repo when initialy created.
+    """ Original Implementation of the gelu activation function in Google Bert repo when initially created.
         For information: OpenAI GPT's gelu is slightly different (and gives slightly different results):
         0.5 * x * (1 + torch.tanh(math.sqrt(2 / math.pi) * (x + 0.044715 * torch.pow(x, 3))))
         Also see https://arxiv.org/abs/1606.08415

transformers/modeling_ctrl.py

@@ -0,0 +1,482 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and HuggingFace Inc. team.
+# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" PyTorch CTRL model."""
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import collections
+import json
+import logging
+import math
+import os
+import sys
+from io import open
+import numpy as np
+import torch
+import torch.nn as nn
+from torch.nn import CrossEntropyLoss
+from torch.nn.parameter import Parameter
+
+from .modeling_utils import PreTrainedModel, Conv1D, prune_conv1d_layer, SequenceSummary
+from .configuration_ctrl import CTRLConfig
+from .file_utils import add_start_docstrings
+
+logger = logging.getLogger(__name__)
+
+CTRL_PRETRAINED_MODEL_ARCHIVE_MAP = {"ctrl": "https://storage.googleapis.com/sf-ctrl/pytorch/seqlen256_v1.bin"}
+
+
+def angle_defn(pos, i, d_model_size):
+    angle_rates = 1 / torch.pow(10000, (2 * (i//2)) / d_model_size)
+    return pos * angle_rates
+
+def positional_encoding(position, d_model_size, dtype):
+    # create the sinusoidal pattern for the positional encoding
+    angle_rads = (angle_defn(torch.arange(position, dtype=dtype).unsqueeze(1),
+                  torch.arange(d_model_size, dtype=dtype).unsqueeze(0),
+                  d_model_size))
+
+    sines = torch.sin(angle_rads[:, 0::2])
+    cosines = torch.cos(angle_rads[:, 1::2])
+
+    pos_encoding = torch.cat([sines, cosines], dim=-1)
+    return pos_encoding
+
+def scaled_dot_product_attention(q, k, v, mask, attention_mask=None, head_mask=None):
+    # calculate attention
+    matmul_qk = torch.matmul(q, k.permute(0,1,3,2))
+
+    dk = k.shape[-1]
+    scaled_attention_logits = matmul_qk / np.sqrt(dk)
+
+    if mask is not None:
+        scaled_attention_logits += (mask * -1e4)
+
+    if attention_mask is not None:
+        # Apply the attention mask
+        scaled_attention_logits = scaled_attention_logits + attention_mask
+
+    attention_weights = torch.softmax(scaled_attention_logits, dim=-1) 
+
+    # Mask heads if we want to
+    if head_mask is not None:
+        attention_weights = attention_weights * head_mask
+
+    output = torch.matmul(attention_weights, v)
+
+    return output, attention_weights
+
+
+class MultiHeadAttention(torch.nn.Module):
+    def __init__(self, d_model_size, num_heads, output_attentions=False):
+        super(MultiHeadAttention, self).__init__()
+        self.output_attentions = output_attentions
+        self.num_heads = num_heads
+        self.d_model_size = d_model_size
+
+        self.depth = int(d_model_size / self.num_heads)
+
+        self.Wq = torch.nn.Linear(d_model_size, d_model_size)
+        self.Wk = torch.nn.Linear(d_model_size, d_model_size)
+        self.Wv = torch.nn.Linear(d_model_size, d_model_size)
+
+        self.dense = torch.nn.Linear(d_model_size, d_model_size)
+
+    def split_into_heads(self, x, batch_size):
+        x = x.reshape(batch_size, -1, self.num_heads, self.depth)
+        return x.permute([0, 2, 1, 3])
+
+    def forward(self, v, k, q, mask, layer_past=None, attention_mask=None, head_mask=None):
+        batch_size = q.shape[0]
+
+        q = self.Wq(q)
+        k = self.Wk(k)
+        v = self.Wv(v)
+
+        q = self.split_into_heads(q, batch_size)
+        k = self.split_into_heads(k, batch_size)
+        v = self.split_into_heads(v, batch_size)
+        if layer_past is not None:
+            past_key, past_value = layer_past[0], layer_past[1]
+            k = torch.cat((past_key, k), dim=-2)
+            v = torch.cat((past_value, v), dim=-2)
+        present = torch.stack((k, v))
+
+        output = scaled_dot_product_attention(q, k, v, mask, attention_mask, head_mask)
+        scaled_attention = output[0].permute([0, 2, 1, 3])
+        attn = output[1]
+        original_size_attention = scaled_attention.reshape(batch_size, -1, self.d_model_size)
+        output = self.dense(original_size_attention)
+
+        outputs = (output, present)
+        if self.output_attentions:
+            outputs = outputs + (attn,)
+        return outputs
+
+
+
+def point_wise_feed_forward_network(d_model_size, dff):
+    return torch.nn.Sequential(torch.nn.Linear(d_model_size, dff),
+                               torch.nn.ReLU(),
+                               torch.nn.Linear(dff, d_model_size))
+
+
+class EncoderLayer(torch.nn.Module):
+    def __init__(self, d_model_size, num_heads, dff, rate=0.1, output_attentions=False):
+        super(EncoderLayer, self).__init__()
+
+        self.multi_head_attention = MultiHeadAttention(d_model_size, num_heads, output_attentions)
+        self.ffn = point_wise_feed_forward_network(d_model_size, dff)
+
+        self.layernorm1 = torch.nn.LayerNorm(d_model_size, eps=1e-6)
+        self.layernorm2 = torch.nn.LayerNorm(d_model_size, eps=1e-6)
+
+        self.dropout1 = torch.nn.Dropout(rate)
+        self.dropout2 = torch.nn.Dropout(rate)
+
+    def forward(self, x, mask, layer_past=None, attention_mask=None, head_mask=None):
+        normed = self.layernorm1(x)
+        attn_outputs = self.multi_head_attention(normed, normed, normed, mask,
+                                                      layer_past=layer_past,
+                                                      attention_mask=attention_mask,
+                                                      head_mask=head_mask)
+        attn_output = attn_outputs[0]
+        attn_output = self.dropout1(attn_output)
+        out1 = x + attn_output
+
+        out2 = self.layernorm2(out1)
+        ffn_output = self.ffn(out2)
+        ffn_output = self.dropout2(ffn_output)
+        out2 = out1 + ffn_output
+
+        outputs = (out2,) + attn_outputs[1:]
+        return outputs
+
+
+class CTRLPreTrainedModel(PreTrainedModel):
+    """ An abstract class to handle weights initialization and
+        a simple interface for dowloading and loading pretrained models.
+    """
+    config_class = CTRLConfig
+    pretrained_model_archive_map = CTRL_PRETRAINED_MODEL_ARCHIVE_MAP
+    base_model_prefix = "transformer"
+
+    def _init_weights(self, module):
+        """ Initialize the weights.
+        """
+        if isinstance(module, (nn.Linear, nn.Embedding, Conv1D)):
+            # Slightly different from the TF version which uses truncated_normal for initialization
+            # cf https://github.com/pytorch/pytorch/pull/5617
+            module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
+            if isinstance(module, (nn.Linear, Conv1D)) and module.bias is not None:
+                module.bias.data.zero_()
+        elif isinstance(module, nn.LayerNorm):
+            module.bias.data.zero_()
+            module.weight.data.fill_(1.0)
+
+
+CTRL_START_DOCSTRING = r"""    CTRL model was proposed in 
+    `CTRL: A Conditional Transformer Language Model for Controllable Generation`_
+    by Nitish Shirish Keskar*, Bryan McCann*, Lav R. Varshney, Caiming Xiong and Richard Socher.
+    It's a causal (unidirectional) transformer pre-trained using language modeling on a very large
+    corpus of ~140 GB of text data with the first token reserved as a control code (such as Links, Books, Wikipedia etc.).
+
+    This model is a PyTorch `torch.nn.Module`_ sub-class. Use it as a regular PyTorch Module and
+    refer to the PyTorch documentation for all matter related to general usage and behavior.
+
+    .. _`CTRL: A Conditional Transformer Language Model for Controllable Generation`:
+        https://www.github.com/salesforce/ctrl
+
+    .. _`torch.nn.Module`:
+        https://pytorch.org/docs/stable/nn.html#module
+
+    Parameters:
+        config (:class:`~transformers.CTRLConfig`): Model configuration class with all the parameters of the model.
+            Initializing with a config file does not load the weights associated with the model, only the configuration.
+            Check out the :meth:`~transformers.PreTrainedModel.from_pretrained` method to load the model weights.
+"""
+
+CTRL_INPUTS_DOCSTRING = r"""    Inputs:
+        **input_ids**: ``torch.LongTensor`` of shape ``(batch_size, sequence_length)``:
+            Indices of input sequence tokens in the vocabulary.
+            CTRL is a model with absolute position embeddings so it's usually advised to pad the inputs on
+            the right rather than the left.
+            Indices can be obtained using :class:`transformers.CTRLTokenizer`.
+            See :func:`transformers.PreTrainedTokenizer.encode` and
+            :func:`transformers.PreTrainedTokenizer.convert_tokens_to_ids` for details.
+        **past**:
+            list of ``torch.FloatTensor`` (one for each layer):
+            that contains pre-computed hidden-states (key and values in the attention blocks) as computed by the model
+            (see `past` output below). Can be used to speed up sequential decoding.
+        **attention_mask**: (`optional`) ``torch.FloatTensor`` of shape ``(batch_size, sequence_length)``:
+            Mask to avoid performing attention on padding token indices.
+            Mask values selected in ``[0, 1]``:
+            ``1`` for tokens that are NOT MASKED, ``0`` for MASKED tokens.
+        **token_type_ids**: (`optional`) ``torch.LongTensor`` of shape ``(batch_size, sequence_length)``:
+            A parallel sequence of tokens (can be used to indicate various portions of the inputs).
+            The embeddings from these tokens will be summed with the respective token embeddings.
+            Indices are selected in the vocabulary (unlike BERT which has a specific vocabulary for segment indices).
+        **position_ids**: (`optional`) ``torch.LongTensor`` of shape ``(batch_size, sequence_length)``:
+            Indices of positions of each input sequence tokens in the position embeddings.
+            Selected in the range ``[0, config.max_position_embeddings - 1]``.
+        **head_mask**: (`optional`) ``torch.FloatTensor`` of shape ``(num_heads,)`` or ``(num_layers, num_heads)``:
+            Mask to nullify selected heads of the self-attention modules.
+            Mask values selected in ``[0, 1]``:
+            ``1`` indicates the head is **not masked**, ``0`` indicates the head is **masked**.
+"""
+
+@add_start_docstrings("The bare CTRL Model transformer outputting raw hidden-states without any specific head on top.",
+                                            CTRL_START_DOCSTRING, CTRL_INPUTS_DOCSTRING)
+class CTRLModel(CTRLPreTrainedModel):
+    r"""
+    Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
+        **last_hidden_state**: ``torch.FloatTensor`` of shape ``(batch_size, sequence_length, hidden_size)``
+            Sequence of hidden-states at the last layer of the model.
+        **past**:
+            list of ``torch.FloatTensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            that contains pre-computed hidden-states (key and values in the attention blocks).
+            Can be used (see `past` input) to speed up sequential decoding.
+        **hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
+            list of ``torch.FloatTensor`` (one for the output of each layer + the output of the embeddings)
+            of shape ``(batch_size, sequence_length, hidden_size)``:
+            Hidden-states of the model at the output of each layer plus the initial embedding outputs.
+        **attentions**: (`optional`, returned when ``config.output_attentions=True``)
+            list of ``torch.FloatTensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.
+
+    Examples::
+
+        tokenizer = CTRLTokenizer.from_pretrained('ctrl')
+        model = CTRLModel.from_pretrained('ctrl')
+        input_ids = torch.tensor(tokenizer.encode("Links Hello, my dog is cute")).unsqueeze(0)  # Batch size 1
+        outputs = model(input_ids)
+        last_hidden_states = outputs[0]  # The last hidden-state is the first element of the output tuple
+
+    """
+    def __init__(self, config):
+        super(CTRLModel, self).__init__(config)
+        self.output_hidden_states = config.output_hidden_states
+        self.d_model_size = config.n_embd
+        self.num_layers = config.n_layer
+        
+        self.pos_encoding = positional_encoding(config.n_positions, self.d_model_size, torch.float)
+            
+        self.output_attentions = config.output_attentions
+
+        self.w = nn.Embedding(config.vocab_size, config.n_embd)
+
+        
+        self.dropout = nn.Dropout(config.embd_pdrop)
+        self.h = nn.ModuleList([EncoderLayer(config.n_embd,
+                                             config.n_head,
+                                             config.dff,
+                                             config.resid_pdrop,
+                                             config.output_attentions) for _ in range(config.n_layer)])
+        self.layernorm = nn.LayerNorm(config.n_embd, eps=config.layer_norm_epsilon)
+
+        self.init_weights()
+
+    def _resize_token_embeddings(self, new_num_tokens):
+        self.w = self._get_resized_embeddings(self.w, new_num_tokens)
+        return self.w
+
+    def _prune_heads(self, heads_to_prune):
+        """ Prunes heads of the model.
+                heads_to_prune: dict of {layer_num: list of heads to prune in this layer}
+        """
+        for layer, heads in heads_to_prune.items():
+            self.h[layer].attn.prune_heads(heads)
+
+    def forward(self, input_ids, past=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None):
+        input_shape = input_ids.size()
+        input_ids = input_ids.view(-1, input_shape[-1])
+        if past is None:
+            past_length = 0
+            past = [None] * len(self.h)
+        else:
+            past_length = past[0][0].size(-2)
+        if position_ids is None:
+            position_ids = torch.arange(past_length, input_ids.size(-1) + past_length, dtype=torch.long, device=input_ids.device)
+            position_ids = position_ids.unsqueeze(0).expand_as(input_ids)
+
+        # Attention mask.
+        if attention_mask is not None:
+            attention_mask = attention_mask.view(-1, input_shape[-1])
+            # We create a 3D attention mask from a 2D tensor mask.
+            # Sizes are [batch_size, 1, 1, to_seq_length]
+            # So we can broadcast to [batch_size, num_heads, from_seq_length, to_seq_length]
+            # this attention mask is more simple than the triangular masking of causal attention
+            # used in OpenAI GPT, we just need to prepare the broadcast dimension here.
+            attention_mask = attention_mask.unsqueeze(1).unsqueeze(2)
+
+            # Since attention_mask is 1.0 for positions we want to attend and 0.0 for
+            # masked positions, this operation will create a tensor which is 0.0 for
+            # positions we want to attend and -10000.0 for masked positions.
+            # Since we are adding it to the raw scores before the softmax, this is
+            # effectively the same as removing these entirely.
+            attention_mask = attention_mask.to(dtype=next(self.parameters()).dtype) # fp16 compatibility
+            attention_mask = (1.0 - attention_mask) * -10000.0
+
+        # Prepare head mask if needed
+        # 1.0 in head_mask indicate we keep the head
+        # attention_probs has shape bsz x n_heads x N x N
+        # head_mask has shape n_layer x batch x n_heads x N x N
+        if head_mask is not None:
+            if head_mask.dim() == 1:
+                head_mask = head_mask.unsqueeze(0).unsqueeze(0).unsqueeze(-1).unsqueeze(-1)
+                head_mask = head_mask.expand(self.config.n_layer, -1, -1, -1, -1)
+            elif head_mask.dim() == 2:
+                head_mask = head_mask.unsqueeze(1).unsqueeze(-1).unsqueeze(-1)  # We can specify head_mask for each layer
+            head_mask = head_mask.to(dtype=next(self.parameters()).dtype) # switch to fload if need + fp16 compatibility
+        else:
+            head_mask = [None] * self.config.n_layer
+
+        if token_type_ids is not None:
+            token_type_ids = token_type_ids.view(-1, input_shape[-1])
+            token_type_embeds = self.w(token_type_ids)
+            token_type_embeds *= np.sqrt(self.d_model_size)
+        else:
+            token_type_embeds = 0
+        position_ids = position_ids.view(-1, input_shape[-1])
+
+        inputs_embeds = self.w(input_ids)
+        # inputs_embeds = embedded.unsqueeze(0) if len(input_ids.shape)<2 else embedded
+        seq_len = input_ids.shape[-1]
+        mask = torch.triu(torch.ones(seq_len, seq_len), 1).to(inputs_embeds.device)
+
+        inputs_embeds *= np.sqrt(self.d_model_size)
+
+        pos_embeds = self.pos_encoding[position_ids, :].to(inputs_embeds.device)
+
+        hidden_states = inputs_embeds + pos_embeds + token_type_embeds
+
+        hidden_states = self.dropout(hidden_states)
+
+        output_shape = input_shape + (inputs_embeds.size(-1),)
+        presents = ()
+        all_hidden_states = ()
+        all_attentions = []
+        for i, (h, layer_past) in enumerate(zip(self.h, past)):
+            if self.output_hidden_states:
+                all_hidden_states = all_hidden_states + (hidden_states.view(*output_shape),)
+            outputs = h(hidden_states,
+                        mask,
+                        layer_past=layer_past,
+                        attention_mask=attention_mask,
+                        head_mask=head_mask[i])
+            hidden_states, present = outputs[:2]
+            presents = presents + (present,)
+
+            if self.output_attentions:
+                all_attentions.append(outputs[2])
+
+        hidden_states = self.layernorm(hidden_states)
+        hidden_states = hidden_states.view(*output_shape)
+        if self.output_hidden_states:
+            all_hidden_states = all_hidden_states + (hidden_states,)
+
+        outputs = (hidden_states, presents)
+        if self.output_hidden_states:
+            outputs = outputs + (all_hidden_states,)
+        if self.output_attentions:
+            # let the number of heads free (-1) so we can extract attention even after head pruning
+            attention_output_shape = input_shape[:-1] + (-1,) + all_attentions[0].shape[-2:]
+            all_attentions = tuple(t.view(*attention_output_shape) for t in all_attentions)
+            outputs = outputs + (all_attentions,)
+        return outputs
+
+
+@add_start_docstrings("""The CTRL Model transformer with a language modeling head on top
+(linear layer with weights tied to the input embeddings). """, CTRL_START_DOCSTRING, CTRL_INPUTS_DOCSTRING)
+class CTRLLMHeadModel(CTRLPreTrainedModel):
+    r"""
+        **labels**: (`optional`) ``torch.LongTensor`` of shape ``(batch_size, sequence_length)``:
+            Labels for language modeling.
+            Note that the labels **are shifted** inside the model, i.e. you can set ``lm_labels = input_ids``
+            Indices are selected in ``[-1, 0, ..., config.vocab_size]``
+            All labels set to ``-1`` are ignored (masked), the loss is only
+            computed for labels in ``[0, ..., config.vocab_size]``
+
+    Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
+        **loss**: (`optional`, returned when ``labels`` is provided) ``torch.FloatTensor`` of shape ``(1,)``:
+            Language modeling loss.
+        **prediction_scores**: ``torch.FloatTensor`` of shape ``(batch_size, sequence_length, config.vocab_size)``
+            Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
+        **past**:
+            list of ``torch.FloatTensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            that contains pre-computed hidden-states (key and values in the attention blocks).
+            Can be used (see `past` input) to speed up sequential decoding.
+        **hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
+            list of ``torch.FloatTensor`` (one for the output of each layer + the output of the embeddings)
+            of shape ``(batch_size, sequence_length, hidden_size)``:
+            Hidden-states of the model at the output of each layer plus the initial embedding outputs.
+        **attentions**: (`optional`, returned when ``config.output_attentions=True``)
+            list of ``torch.FloatTensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.
+
+    Examples::
+
+        import torch
+        from transformers import CTRLTokenizer, CTRLLMHeadModel
+
+        tokenizer = CTRLTokenizer.from_pretrained('ctrl')
+        model = CTRLLMHeadModel.from_pretrained('ctrl')
+
+        input_ids = torch.tensor(tokenizer.encode("Links Hello, my dog is cute")).unsqueeze(0)  # Batch size 1
+        outputs = model(input_ids, labels=input_ids)
+        loss, logits = outputs[:2]
+
+    """
+    def __init__(self, config):
+        super(CTRLLMHeadModel, self).__init__(config)
+        self.transformer = CTRLModel(config)
+        self.lm_head = nn.Linear(config.n_embd, config.vocab_size, bias=True)
+
+        self.init_weights()
+        self.tie_weights()
+
+    def tie_weights(self):
+        """ Make sure we are sharing the input and output embeddings.
+                Export to TorchScript can't handle parameter sharing so we are cloning them instead.
+        """
+        self._tie_or_clone_weights(self.lm_head, self.transformer.w)
+
+    def forward(self, input_ids, past=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None,
+                labels=None):
+        transformer_outputs = self.transformer(input_ids,
+                                               past=past,
+                                               attention_mask=attention_mask,
+                                               token_type_ids=token_type_ids,
+                                               position_ids=position_ids,
+                                               head_mask=head_mask)
+
+        hidden_states = transformer_outputs[0]
+
+        lm_logits = self.lm_head(hidden_states)
+
+        outputs = (lm_logits,) + transformer_outputs[1:]
+
+        if labels is not None:
+            # Shift so that tokens < n predict n
+            shift_logits = lm_logits[..., :-1, :].contiguous()
+            shift_labels = labels[..., 1:].contiguous()
+            # Flatten the tokens
+            loss_fct = CrossEntropyLoss(ignore_index=-1)
+            loss = loss_fct(shift_logits.view(-1, shift_logits.size(-1)),
+                            shift_labels.view(-1))
+            outputs = (loss,) + outputs
+
+        return outputs  # (loss), lm_logits, presents, (all hidden_states), (attentions)

transformers/modeling_distilbert.py

@@ -159,8 +159,6 @@ class MultiHeadSelfAttention(nn.Module):
 
         dim_per_head = self.dim // self.n_heads
 
-        assert 2 <= mask.dim() <= 3
-        causal = (mask.dim() == 3)
         mask_reshp = (bs, 1, 1, k_length)
 
         def shape(x):
@@ -649,7 +647,7 @@ class DistilBertForQuestionAnswering(DistilBertPreTrainedModel):
         start_positions = torch.tensor([1])
         end_positions = torch.tensor([3])
         outputs = model(input_ids, start_positions=start_positions, end_positions=end_positions)
-        loss, start_scores, end_scores = outputs[:2]
+        loss, start_scores, end_scores = outputs[:3]
 
     """
     def __init__(self, config):

transformers/modeling_gpt2.py

@@ -38,7 +38,8 @@ logger = logging.getLogger(__name__)
 
 GPT2_PRETRAINED_MODEL_ARCHIVE_MAP = {"gpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-pytorch_model.bin",
                                      "gpt2-medium": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-medium-pytorch_model.bin",
-                                     "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-pytorch_model.bin"}
+                                     "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-pytorch_model.bin",
+                                     "distilgpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/distilgpt2-pytorch_model.bin",}
 
 def load_tf_weights_in_gpt2(model, config, gpt2_checkpoint_path):
     """ Load tf checkpoints in a pytorch model

transformers/modeling_openai.py

@@ -170,7 +170,7 @@ class Attention(nn.Module):
         # w = w * self.bias + -1e9 * (1 - self.bias)  # TF implem method: mask_attn_weights
         # XD: self.b may be larger than w, so we need to crop it
         b = self.bias[:, :, : w.size(-2), : w.size(-1)]
-        w = w * b + -1e9 * (1 - b)
+        w = w * b + - 1e4 * (1 - b)
 
         if attention_mask is not None:
             # Apply the attention mask

transformers/modeling_roberta.py

@@ -43,6 +43,9 @@ class RobertaEmbeddings(BertEmbeddings):
     def __init__(self, config):
         super(RobertaEmbeddings, self).__init__(config)
         self.padding_idx = 1
+        self.word_embeddings = nn.Embedding(config.vocab_size, config.hidden_size, padding_idx=self.padding_idx)
+        self.position_embeddings = nn.Embedding(config.max_position_embeddings, config.hidden_size,
+                                                padding_idx=self.padding_idx)
 
     def forward(self, input_ids, token_type_ids=None, position_ids=None):
         seq_length = input_ids.size(1)
@@ -169,7 +172,8 @@ class RobertaModel(BertModel):
         if input_ids[:, 0].sum().item() != 0:
             logger.warning("A sequence with no special tokens has been passed to the RoBERTa model. "
                            "This model requires special tokens in order to work. "
-                           "Please specify add_special_tokens=True in your encoding.")
+                           "Please specify add_special_tokens=True in your tokenize.encode()"
+                           "or tokenizer.convert_tokens_to_ids().")
         return super(RobertaModel, self).forward(input_ids,
                                                  attention_mask=attention_mask,
                                                  token_type_ids=token_type_ids,

transformers/modeling_tf_bert.py

@@ -62,7 +62,7 @@ def load_bert_pt_weights_in_tf2(tf_model, pytorch_checkpoint_path):
 
 def gelu(x):
     """ Gaussian Error Linear Unit.
-    Original Implementation of the gelu activation function in Google Bert repo when initialy created.
+    Original Implementation of the gelu activation function in Google Bert repo when initially created.
         For information: OpenAI GPT's gelu is slightly different (and gives slightly different results):
         0.5 * x * (1 + torch.tanh(math.sqrt(2 / math.pi) * (x + 0.044715 * torch.pow(x, 3))))
         Also see https://arxiv.org/abs/1606.08415

transformers/modeling_tf_ctrl.py

@@ -0,0 +1,491 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and HuggingFace Inc. team.
+# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" TF 2.0 CTRL model."""
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import logging
+import os
+import sys
+from io import open
+import numpy as np
+import tensorflow as tf
+
+from .configuration_ctrl import CTRLConfig
+from .modeling_tf_utils import TFPreTrainedModel, get_initializer, shape_list, TFSharedEmbeddings
+from .file_utils import add_start_docstrings
+from .modeling_tf_pytorch_utils import load_pytorch_checkpoint_in_tf2_model
+
+logger = logging.getLogger(__name__)
+
+TF_CTRL_PRETRAINED_MODEL_ARCHIVE_MAP = {"ctrl": "https://s3.amazonaws.com/models.huggingface.co/bert/ctrl-tf_model.h5"}
+
+def load_ctrl_pt_weights_in_tf2(tf_model, pytorch_checkpoint_path):
+    # build the network
+    inputs_list = [[7, 6, 0, 0, 1], [1, 2, 3, 0, 0], [0, 0, 0, 4, 5]]
+    tf_inputs = tf.constant(inputs_list)
+    tfo = tf_model(tf_inputs, training=False)
+    return load_pytorch_checkpoint_in_tf2_model(tf_model, pytorch_checkpoint_path, tf_inputs=tf_inputs)
+
+
+def angle_defn(pos, i, d_model_size):
+    angle_rates = 1 / np.power(10000, (2 * (i//2)) / np.float32(d_model_size))
+    return pos * angle_rates
+
+def positional_encoding(position, d_model_size):
+    # create the sinusoidal pattern for the positional encoding
+    angle_rads = angle_defn(np.arange(position)[:, np.newaxis],
+                            np.arange(d_model_size)[np.newaxis, :],
+                            d_model_size)
+
+    sines = np.sin(angle_rads[:, 0::2])
+    cosines = np.cos(angle_rads[:, 1::2])
+
+    # pos_encoding = tf.cast(np.concatenate([sines, cosines], axis=-1)[np.newaxis, ...], dtype=tf.float32)
+    pos_encoding = tf.cast(np.concatenate([sines, cosines], axis=-1), dtype=tf.float32)
+    return pos_encoding
+
+def scaled_dot_product_attention(q, k, v, mask, attention_mask=None, head_mask=None):
+    # calculate attention
+    matmul_qk = tf.matmul(q, k, transpose_b=True)
+    
+    dk = tf.cast(shape_list(k)[-1], tf.float32)
+    scaled_attention_logits = matmul_qk / tf.math.sqrt(dk)
+
+    if mask is not None:
+        scaled_attention_logits += (mask * -1e4)
+
+    if attention_mask is not None:
+        # Apply the attention mask
+        scaled_attention_logits = scaled_attention_logits + attention_mask
+
+    attention_weights = tf.nn.softmax(scaled_attention_logits, axis=-1) 
+
+    # Mask heads if we want to
+    if head_mask is not None:
+        attention_weights = attention_weights * head_mask
+
+    output = tf.matmul(attention_weights, v) 
+
+    return output, attention_weights
+
+
+class TFMultiHeadAttention(tf.keras.layers.Layer):
+    def __init__(self, d_model_size, num_heads, output_attentions=False, **kwargs):
+        super(TFMultiHeadAttention, self).__init__(**kwargs)
+        self.output_attentions = output_attentions
+        self.num_heads = num_heads
+        self.d_model_size = d_model_size
+
+        self.depth = int(d_model_size / self.num_heads)
+
+        self.Wq = tf.keras.layers.Dense(d_model_size, name='Wq')
+        self.Wk = tf.keras.layers.Dense(d_model_size, name='Wk')
+        self.Wv = tf.keras.layers.Dense(d_model_size, name='Wv')
+
+        self.dense = tf.keras.layers.Dense(d_model_size, name='dense')
+
+    def split_into_heads(self, x, batch_size):
+        x = tf.reshape(x, (batch_size, -1, self.num_heads, self.depth))
+        return tf.transpose(x, perm=[0, 2, 1, 3])
+
+    def call(self, inputs, training=False):
+        v, k, q, mask, layer_past, attention_mask, head_mask = inputs
+        batch_size = q.shape[0]
+
+        q = self.Wq(q)
+        k = self.Wk(k)
+        v = self.Wv(v)
+
+        q = self.split_into_heads(q, batch_size)
+        k = self.split_into_heads(k, batch_size)
+        v = self.split_into_heads(v, batch_size)
+        if layer_past is not None:
+            past_key, past_value = tf.unstack(layer_past, axis=1)
+            k = tf.concat((past_key, k), dim=-2)
+            v = tf.concat((past_value, v), dim=-2)
+        present = tf.stack((k, v), axis=1)
+
+        output = scaled_dot_product_attention(q, k, v, mask, attention_mask, head_mask)
+        scaled_attention = tf.transpose(output[0], perm=[0, 2, 1, 3])
+        attn = output[1]
+        original_size_attention = tf.reshape(scaled_attention,  (batch_size, -1, self.d_model_size))
+        output = self.dense(original_size_attention)
+
+        outputs = (output, present)
+        if self.output_attentions:
+            outputs = outputs + (attn,)
+        return outputs
+
+
+
+def point_wise_feed_forward_network(d_model_size, dff, name=""):
+    return tf.keras.Sequential([
+            tf.keras.layers.Dense(dff, activation='relu', name="0"), 
+            tf.keras.layers.Dense(d_model_size, name="2")
+        ], name="ffn")
+
+
+class TFEncoderLayer(tf.keras.layers.Layer):
+    def __init__(self, d_model_size, num_heads, dff, rate=0.1, layer_norm_epsilon=1e-6, output_attentions=False, **kwargs):
+        super(TFEncoderLayer, self).__init__(**kwargs)
+
+        self.multi_head_attention = TFMultiHeadAttention(d_model_size,
+                                                         num_heads,
+                                                         output_attentions,
+                                                         name="multi_head_attention")
+        self.ffn = point_wise_feed_forward_network(d_model_size, dff, name="ffn")
+
+        self.layernorm1 = tf.keras.layers.LayerNormalization(epsilon=layer_norm_epsilon, name="layernorm1")
+        self.layernorm2 = tf.keras.layers.LayerNormalization(epsilon=layer_norm_epsilon, name="layernorm2")
+
+        self.dropout1 = tf.keras.layers.Dropout(rate)
+        self.dropout2 = tf.keras.layers.Dropout(rate)
+
+    def call(self, inputs, training=False):
+        x, mask, layer_past, attention_mask, head_mask = inputs
+        normed = self.layernorm1(x)
+        attn_outputs = self.multi_head_attention([normed, normed, normed, mask, layer_past,
+                                                  attention_mask, head_mask], training=training)
+        attn_output = attn_outputs[0]
+        attn_output = self.dropout1(attn_output, training=training)
+        out1 = x + attn_output
+
+        out2 = self.layernorm2(out1)
+        ffn_output = self.ffn(out2)
+        ffn_output = self.dropout2(ffn_output, training=training)
+        out2 = out1 + ffn_output
+
+        outputs = (out2,) + attn_outputs[1:]
+        return outputs
+
+
+class TFCTRLMainLayer(tf.keras.layers.Layer):
+    def __init__(self, config, **kwargs):
+        super(TFCTRLMainLayer, self).__init__(**kwargs)
+        self.output_hidden_states = config.output_hidden_states
+        self.d_model_size = config.n_embd
+        self.num_layers = config.n_layer
+
+        self.pos_encoding = positional_encoding(config.n_positions, self.d_model_size)
+
+        self.output_attentions = config.output_attentions
+
+        self.w = TFSharedEmbeddings(config.vocab_size,
+                                    config.n_embd,
+                                    initializer_range=config.initializer_range,
+                                    name="w")
+
+        self.dropout = tf.keras.layers.Dropout(config.embd_pdrop)
+        self.h = [TFEncoderLayer(config.n_embd,
+                                 config.n_head,
+                                 config.dff,
+                                 config.resid_pdrop,
+                                 config.layer_norm_epsilon,
+                                 config.output_attentions,
+                                 name='h_._{}'.format(i)) for i in range(config.n_layer)]
+        self.layernorm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_epsilon, name="layernorm")
+
+    def _resize_token_embeddings(self, new_num_tokens):
+        raise NotImplementedError
+
+    def _prune_heads(self, heads_to_prune):
+        """ Prunes heads of the model.
+                heads_to_prune: dict of {layer_num: list of heads to prune in this layer}
+        """
+        raise NotImplementedError
+
+    def call(self, inputs, past=None, attention_mask=None, token_type_ids=None, position_ids=None, head_mask=None, training=False):
+        if isinstance(inputs, (tuple, list)):
+            input_ids = inputs[0]
+            past = inputs[1] if len(inputs) > 1 else past
+            attention_mask = inputs[2] if len(inputs) > 2 else attention_mask
+            token_type_ids = inputs[3] if len(inputs) > 3 else token_type_ids
+            position_ids = inputs[4] if len(inputs) > 4 else position_ids
+            head_mask = inputs[5] if len(inputs) > 5 else head_mask
+            assert len(inputs) <= 6, "Too many inputs."
+        elif isinstance(inputs, dict):
+            input_ids = inputs.get('input_ids')
+            past = inputs.get('past', past)
+            attention_mask = inputs.get('attention_mask', attention_mask)
+            token_type_ids = inputs.get('token_type_ids', token_type_ids)
+            position_ids = inputs.get('position_ids', position_ids)
+            head_mask = inputs.get('head_mask', head_mask)
+            assert len(inputs) <= 6, "Too many inputs."
+        else:
+            input_ids = inputs
+
+        input_shape = shape_list(input_ids)
+        input_ids = tf.reshape(input_ids, [-1, input_shape[-1]])
+
+        if past is None:
+            past_length = 0
+            past = [None] * len(self.h)
+        else:
+            past_length = shape_list(past[0][0])[-2]
+        if position_ids is None:
+            position_ids = tf.range(past_length, shape_list(input_ids)[-1] + past_length, dtype=tf.int32)[tf.newaxis, :]
+            position_ids = tf.tile(position_ids, [shape_list(input_ids)[0], 1])
+
+        # Attention mask.
+        if attention_mask is not None:
+            # We create a 3D attention mask from a 2D tensor mask.
+            # Sizes are [batch_size, 1, 1, to_seq_length]
+            # So we can broadcast to [batch_size, num_heads, from_seq_length, to_seq_length]
+            # this attention mask is more simple than the triangular masking of causal attention
+            # used in OpenAI GPT, we just need to prepare the broadcast dimension here.
+            attention_mask = attention_mask[:, tf.newaxis, tf.newaxis, :]
+
+            # Since attention_mask is 1.0 for positions we want to attend and 0.0 for
+            # masked positions, this operation will create a tensor which is 0.0 for
+            # positions we want to attend and -10000.0 for masked positions.
+            # Since we are adding it to the raw scores before the softmax, this is
+            # effectively the same as removing these entirely.
+
+            attention_mask = tf.cast(attention_mask, tf.float32)
+            attention_mask = (1.0 - attention_mask) * -10000.0
+        else:
+            attention_mask = None
+
+        # Prepare head mask if needed
+        # 1.0 in head_mask indicate we keep the head
+        # attention_probs has shape bsz x n_heads x N x N
+        # head_mask has shape n_layer x batch x n_heads x N x N
+        if head_mask is not None:
+            raise NotImplementedError
+        else:
+            head_mask = [None] * self.num_layers
+
+        if token_type_ids is not None:
+            token_type_ids = tf.reshape(token_type_ids, [-1, shape_list(token_type_ids)[-1]])
+            token_type_embeds = self.w(token_type_ids, mode='embedding')
+            token_type_embeds *= tf.math.sqrt(tf.cast(self.d_model_size, tf.float32))
+        else:
+            token_type_embeds = 0
+        position_ids = tf.reshape(position_ids, [-1, shape_list(position_ids)[-1]])
+
+        inputs_embeds = self.w(input_ids, mode='embedding')
+        # x = embedded.unsqueeze(0) if len(input_ids.shape)<2 else embedded
+        seq_len = input_shape[-1]
+        mask = 1 - tf.linalg.band_part(tf.ones((seq_len, seq_len)), -1, 0)
+
+        inputs_embeds *= tf.math.sqrt(tf.cast(self.d_model_size, tf.float32))
+
+        pos_embeds = tf.gather(self.pos_encoding, position_ids)
+
+        hidden_states = inputs_embeds + pos_embeds + token_type_embeds
+
+        hidden_states = self.dropout(hidden_states, training=training)
+
+        output_shape = input_shape + [shape_list(hidden_states)[-1]]
+        presents = ()
+        all_hidden_states = ()
+        all_attentions = []
+        for i, (h, layer_past) in enumerate(zip(self.h, past)):
+            if self.output_hidden_states:
+                all_hidden_states = all_hidden_states + (tf.reshape(hidden_states, output_shape),)
+            outputs = h([hidden_states, mask, layer_past, attention_mask, head_mask[i]], training=training)
+            hidden_states, present = outputs[:2]
+            presents = presents + (present,)
+
+            if self.output_attentions:
+                all_attentions.append(outputs[2])
+
+        hidden_states = self.layernorm(hidden_states)
+        hidden_states = tf.reshape(hidden_states, output_shape)
+        if self.output_hidden_states:
+            all_hidden_states = all_hidden_states + (hidden_states,)
+
+        outputs = (hidden_states, presents)
+        if self.output_hidden_states:
+            outputs = outputs + (all_hidden_states,)
+        if self.output_attentions:
+            # let the number of heads free (-1) so we can extract attention even after head pruning
+            attention_output_shape = input_shape[:-1] + [-1] + shape_list(all_attentions[0])[-2:]
+            all_attentions = tuple(tf.reshape(t, attention_output_shape) for t in all_attentions)
+            outputs = outputs + (all_attentions,)
+        return outputs
+
+
+class TFCTRLPreTrainedModel(TFPreTrainedModel):
+    """ An abstract class to handle weights initialization and
+        a simple interface for dowloading and loading pretrained models.
+    """
+    config_class = CTRLConfig
+    pretrained_model_archive_map = TF_CTRL_PRETRAINED_MODEL_ARCHIVE_MAP
+    base_model_prefix = "transformer"
+    load_pt_weights = load_ctrl_pt_weights_in_tf2
+
+
+CTRL_START_DOCSTRING = r"""    CTRL model was proposed in 
+    `CTRL: A Conditional Transformer Language Model for Controllable Generation`_
+    by Nitish Shirish Keskar*, Bryan McCann*, Lav R. Varshney, Caiming Xiong and Richard Socher.
+    It's a causal (unidirectional) transformer pre-trained using language modeling on a very large
+    corpus of ~140 GB of text data with the first token reserved as a control code (such as Links, Books, Wikipedia etc.).
+
+    This model is a PyTorch `torch.nn.Module`_ sub-class. Use it as a regular PyTorch Module and
+    refer to the PyTorch documentation for all matter related to general usage and behavior.
+
+    .. _`CTRL: A Conditional Transformer Language Model for Controllable Generation`:
+        https://www.github.com/salesforce/ctrl
+
+    .. _`torch.nn.Module`:
+        https://pytorch.org/docs/stable/nn.html#module
+
+    Parameters:
+        config (:class:`~transformers.CTRLConfig`): Model configuration class with all the parameters of the model.
+            Initializing with a config file does not load the weights associated with the model, only the configuration.
+            Check out the :meth:`~transformers.PreTrainedModel.from_pretrained` method to load the model weights.
+"""
+
+CTRL_INPUTS_DOCSTRING = r"""    Inputs:
+        **input_ids**: ``Numpy array`` or ``tf.Tensor`` of shape ``(batch_size, sequence_length)``:
+            Indices of input sequence tokens in the vocabulary.
+            CTRL is a model with absolute position embeddings so it's usually advised to pad the inputs on
+            the right rather than the left.
+            Indices can be obtained using :class:`transformers.CTRLTokenizer`.
+            See :func:`transformers.PreTrainedTokenizer.encode` and
+            :func:`transformers.PreTrainedTokenizer.convert_tokens_to_ids` for details.
+        **past**:
+            list of ``Numpy array`` or ``tf.Tensor`` (one for each layer):
+            that contains pre-computed hidden-states (key and values in the attention blocks) as computed by the model
+            (see `past` output below). Can be used to speed up sequential decoding.
+        **attention_mask**: (`optional`) ``Numpy array`` or ``tf.Tensor`` of shape ``(batch_size, sequence_length)``:
+            Mask to avoid performing attention on padding token indices.
+            Mask values selected in ``[0, 1]``:
+            ``1`` for tokens that are NOT MASKED, ``0`` for MASKED tokens.
+        **token_type_ids**: (`optional`) ``Numpy array`` or ``tf.Tensor`` of shape ``(batch_size, sequence_length)``:
+            A parallel sequence of tokens (can be used to indicate various portions of the inputs).
+            The embeddings from these tokens will be summed with the respective token embeddings.
+            Indices are selected in the vocabulary (unlike BERT which has a specific vocabulary for segment indices).
+        **position_ids**: (`optional`) ``Numpy array`` or ``tf.Tensor`` of shape ``(batch_size, sequence_length)``:
+            Indices of positions of each input sequence tokens in the position embeddings.
+            Selected in the range ``[0, config.max_position_embeddings - 1]``.
+        **head_mask**: (`optional`) ``Numpy array`` or ``tf.Tensor`` of shape ``(num_heads,)`` or ``(num_layers, num_heads)``:
+            Mask to nullify selected heads of the self-attention modules.
+            Mask values selected in ``[0, 1]``:
+            ``1`` indicates the head is **not masked**, ``0`` indicates the head is **masked**.
+"""
+
+@add_start_docstrings("The bare CTRL Model transformer outputting raw hidden-states without any specific head on top.",
+                                            CTRL_START_DOCSTRING, CTRL_INPUTS_DOCSTRING)
+class TFCTRLModel(TFCTRLPreTrainedModel):
+    r"""
+    Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
+        **last_hidden_state**: ``tf.Tensor`` of shape ``(batch_size, sequence_length, hidden_size)``
+            Sequence of hidden-states at the last layer of the model.
+        **past**:
+            list of ``tf.Tensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            that contains pre-computed hidden-states (key and values in the attention blocks).
+            Can be used (see `past` input) to speed up sequential decoding.
+        **hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
+            list of ``tf.Tensor`` (one for the output of each layer + the output of the embeddings)
+            of shape ``(batch_size, sequence_length, hidden_size)``:
+            Hidden-states of the model at the output of each layer plus the initial embedding outputs.
+        **attentions**: (`optional`, returned when ``config.output_attentions=True``)
+            list of ``tf.Tensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.
+
+    Examples::
+
+        import tensorflow as tf
+        from transformers import CTRLTokenizer, TFCTRLModel
+
+        tokenizer = CTRLTokenizer.from_pretrained('ctrl')
+        model = TFCTRLModel.from_pretrained('ctrl')
+        input_ids = tf.constant(tokenizer.encode("Hello, my dog is cute"))[None, :]  # Batch size 1
+        outputs = model(input_ids)
+        last_hidden_states = outputs[0]  # The last hidden-state is the first element of the output tuple
+
+    """
+    def __init__(self, config, *inputs, **kwargs):
+        super(TFCTRLModel, self).__init__(config, *inputs, **kwargs)
+        self.transformer = TFCTRLMainLayer(config, name='transformer')
+
+    def call(self, inputs, **kwargs):
+        outputs = self.transformer(inputs, **kwargs)
+        return outputs
+
+
+class TFCTRLLMHead(tf.keras.layers.Layer):
+    def __init__(self, config, input_embeddings, **kwargs):
+        super(TFCTRLLMHead, self).__init__(**kwargs)
+        self.vocab_size = config.vocab_size
+
+        # The output weights are the same as the input embeddings, but there is
+        # an output-only bias for each token.
+        self.input_embeddings = input_embeddings
+
+    def build(self, input_shape):
+        self.bias = self.add_weight(shape=(self.vocab_size,),
+                                    initializer='zeros',
+                                    trainable=True,
+                                    name='bias')
+        super(TFCTRLLMHead, self).build(input_shape)
+
+    def call(self, hidden_states):
+        hidden_states = self.input_embeddings(hidden_states, mode="linear")
+        hidden_states = hidden_states + self.bias
+        return hidden_states
+
+
+@add_start_docstrings("""The CTRL Model transformer with a language modeling head on top
+(linear layer with weights tied to the input embeddings). """, CTRL_START_DOCSTRING, CTRL_INPUTS_DOCSTRING)
+class TFCTRLLMHeadModel(TFCTRLPreTrainedModel):
+    r"""
+    Outputs: `Tuple` comprising various elements depending on the configuration (config) and inputs:
+        **prediction_scores**: ``torch.FloatTensor`` of shape ``(batch_size, sequence_length, config.vocab_size)``
+            Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
+        **past**:
+            list of ``tf.Tensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            that contains pre-computed hidden-states (key and values in the attention blocks).
+            Can be used (see `past` input) to speed up sequential decoding.
+        **hidden_states**: (`optional`, returned when ``config.output_hidden_states=True``)
+            list of ``tf.Tensor`` (one for the output of each layer + the output of the embeddings)
+            of shape ``(batch_size, sequence_length, hidden_size)``:
+            Hidden-states of the model at the output of each layer plus the initial embedding outputs.
+        **attentions**: (`optional`, returned when ``config.output_attentions=True``)
+            list of ``tf.Tensor`` (one for each layer) of shape ``(batch_size, num_heads, sequence_length, sequence_length)``:
+            Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.
+
+    Examples::
+
+        import torch
+        from transformers import CTRLTokenizer, TFCTRLLMHeadModel
+
+        tokenizer = CTRLTokenizer.from_pretrained('ctrl')
+        model = TFCTRLLMHeadModel.from_pretrained('ctrl')
+
+        input_ids = torch.tensor(tokenizer.encode("Links Hello, my dog is cute")).unsqueeze(0)  # Batch size 1
+        outputs = model(input_ids, labels=input_ids)
+        loss, logits = outputs[:2]
+
+    """
+    def __init__(self, config, *inputs, **kwargs):
+        super(TFCTRLLMHeadModel, self).__init__(config, *inputs, **kwargs)
+        self.transformer = TFCTRLMainLayer(config, name='transformer')
+
+        self.lm_head = TFCTRLLMHead(config, self.transformer.w, name="lm_head")
+
+    def call(self, inputs, **kwargs):
+        transformer_outputs = self.transformer(inputs, **kwargs)
+        hidden_states = transformer_outputs[0]
+
+        lm_logits = self.lm_head(hidden_states)
+
+        outputs = (lm_logits,) + transformer_outputs[1:]
+
+        return outputs  # lm_logits, presents, (all hidden_states), (attentions)

transformers/modeling_tf_distilbert.py

@@ -45,7 +45,7 @@ TF_DISTILBERT_PRETRAINED_MODEL_ARCHIVE_MAP = {
 ### UTILS AND BUILDING BLOCKS OF THE ARCHITECTURE ###
 def gelu(x):
     """ Gaussian Error Linear Unit.
-    Original Implementation of the gelu activation function in Google Bert repo when initialy created.
+    Original Implementation of the gelu activation function in Google Bert repo when initially created.
         For information: OpenAI GPT's gelu is slightly different (and gives slightly different results):
         0.5 * x * (1 + torch.tanh(math.sqrt(2 / math.pi) * (x + 0.044715 * torch.pow(x, 3))))
         Also see https://arxiv.org/abs/1606.08415
@@ -226,8 +226,6 @@ class TFMultiHeadSelfAttention(tf.keras.layers.Layer):
 
         dim_per_head = self.dim // self.n_heads
 
-        assert 2 <= len(tf.shape(mask)) <= 3
-        causal = (len(tf.shape(mask)) == 3)
         mask_reshape = [bs, 1, 1, k_length]
 
         def shape(x):
@@ -603,7 +601,7 @@ class TFDistilBertForMaskedLM(TFDistilBertPreTrainedModel):
         tokenizer = DistilBertTokenizer.from_pretrained('distilbert-base-uncased')
         model = TFDistilBertForMaskedLM.from_pretrained('distilbert-base-uncased')
         input_ids = tf.constant(tokenizer.encode("Hello, my dog is cute"))[None, :]  # Batch size 1
-        outputs = model(input_ids, masked_lm_labels=input_ids)
+        outputs = model(input_ids)
         prediction_scores = outputs[0]
 
     """
@@ -715,9 +713,7 @@ class TFDistilBertForQuestionAnswering(TFDistilBertPreTrainedModel):
         tokenizer = DistilBertTokenizer.from_pretrained('distilbert-base-uncased')
         model = TFDistilBertForQuestionAnswering.from_pretrained('distilbert-base-uncased')
         input_ids = tf.constant(tokenizer.encode("Hello, my dog is cute"))[None, :]  # Batch size 1
-        start_positions = tf.constant([1])
-        end_positions = tf.constant([3])
-        outputs = model(input_ids, start_positions=start_positions, end_positions=end_positions)
+        outputs = model(input_ids)
         start_scores, end_scores = outputs[:2]
 
     """

transformers/modeling_tf_gpt2.py

@@ -38,7 +38,8 @@ logger = logging.getLogger(__name__)
 
 TF_GPT2_PRETRAINED_MODEL_ARCHIVE_MAP = {"gpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-tf_model.h5",
                                      "gpt2-medium": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-medium-tf_model.h5",
-                                     "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-tf_model.h5"}
+                                     "gpt2-large": "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-tf_model.h5",
+                                     "distilgpt2": "https://s3.amazonaws.com/models.huggingface.co/bert/distilgpt2-tf_model.h5",}
 
 
 def load_gpt2_pt_weights_in_tf2(tf_model, pytorch_checkpoint_path):

transformers/modeling_tf_xlm.py

@@ -69,7 +69,7 @@ def create_sinusoidal_embeddings(n_pos, dim, out):
 
 def gelu(x):
     """ Gaussian Error Linear Unit.
-    Original Implementation of the gelu activation function in Google Bert repo when initialy created.
+    Original Implementation of the gelu activation function in Google Bert repo when initially created.
         For information: OpenAI GPT's gelu is slightly different (and gives slightly different results):
         0.5 * x * (1 + torch.tanh(math.sqrt(2 / math.pi) * (x + 0.044715 * torch.pow(x, 3))))
         Also see https://arxiv.org/abs/1606.08415

transformers/modeling_utils.py

@@ -501,7 +501,10 @@ class PoolerEndLogits(nn.Module):
         x = self.dense_1(x).squeeze(-1)
 
         if p_mask is not None:
-            x = x * (1 - p_mask) - 1e30 * p_mask
+            if next(self.parameters()).dtype == torch.float16:
+                x = x * (1 - p_mask) - 65500 * p_mask
+            else:
+                x = x * (1 - p_mask) - 1e30 * p_mask
 
         return x
 

transformers/tests/modeling_ctrl_test.py

@@ -0,0 +1,215 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and HuggingFace Inc. team.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import unittest
+import pytest
+import shutil
+import pdb
+
+from transformers import is_torch_available
+
+if is_torch_available():
+    from transformers import (CTRLConfig, CTRLModel, CTRL_PRETRAINED_MODEL_ARCHIVE_MAP,
+                                    CTRLLMHeadModel)
+else:
+    pytestmark = pytest.mark.skip("Require Torch")
+
+from .modeling_common_test import (CommonTestCases, ids_tensor)
+from .configuration_common_test import ConfigTester
+
+
+class CTRLModelTest(CommonTestCases.CommonModelTester):
+
+    all_model_classes = (CTRLModel, CTRLLMHeadModel) if is_torch_available() else ()
+    test_pruning = False
+    test_torchscript = False
+    test_resize_embeddings = False
+    test_head_masking = False
+
+    class CTRLModelTester(object):
+
+        def __init__(self,
+                     parent,
+                     batch_size=13,
+                     seq_length=7,
+                     is_training=True,
+                     use_token_type_ids=True,
+                     use_input_mask=True,
+                     use_labels=True,
+                     use_mc_token_ids=True,
+                     vocab_size=99,
+                     hidden_size=32,
+                     num_hidden_layers=5,
+                     num_attention_heads=4,
+                     intermediate_size=37,
+                     hidden_act="gelu",
+                     hidden_dropout_prob=0.1,
+                     attention_probs_dropout_prob=0.1,
+                     max_position_embeddings=512,
+                     type_vocab_size=16,
+                     type_sequence_label_size=2,
+                     initializer_range=0.02,
+                     num_labels=3,
+                     num_choices=4,
+                     scope=None,
+                     ):
+            self.parent = parent
+            self.batch_size = batch_size
+            self.seq_length = seq_length
+            self.is_training = is_training
+            self.use_token_type_ids = use_token_type_ids
+            self.use_input_mask = use_input_mask
+            self.use_labels = use_labels
+            self.use_mc_token_ids = use_mc_token_ids
+            self.vocab_size = vocab_size
+            self.hidden_size = hidden_size
+            self.num_hidden_layers = num_hidden_layers
+            self.num_attention_heads = num_attention_heads
+            self.intermediate_size = intermediate_size
+            self.hidden_act = hidden_act
+            self.hidden_dropout_prob = hidden_dropout_prob
+            self.attention_probs_dropout_prob = attention_probs_dropout_prob
+            self.max_position_embeddings = max_position_embeddings
+            self.type_vocab_size = type_vocab_size
+            self.type_sequence_label_size = type_sequence_label_size
+            self.initializer_range = initializer_range
+            self.num_labels = num_labels
+            self.num_choices = num_choices
+            self.scope = scope
+
+        def prepare_config_and_inputs(self):
+            input_ids = ids_tensor([self.batch_size, self.seq_length], self.vocab_size)
+
+            input_mask = None
+            if self.use_input_mask:
+                input_mask = ids_tensor([self.batch_size, self.seq_length], vocab_size=2)
+
+            token_type_ids = None
+            if self.use_token_type_ids:
+                token_type_ids = ids_tensor([self.batch_size, self.seq_length], self.type_vocab_size)
+
+            mc_token_ids = None
+            if self.use_mc_token_ids:
+                mc_token_ids = ids_tensor([self.batch_size, self.num_choices], self.seq_length)
+
+            sequence_labels = None
+            token_labels = None
+            choice_labels = None
+            if self.use_labels:
+                sequence_labels = ids_tensor([self.batch_size], self.type_sequence_label_size)
+                token_labels = ids_tensor([self.batch_size, self.seq_length], self.num_labels)
+                choice_labels = ids_tensor([self.batch_size], self.num_choices)
+
+            config = CTRLConfig(
+                vocab_size_or_config_json_file=self.vocab_size,
+                n_embd=self.hidden_size,
+                n_layer=self.num_hidden_layers,
+                n_head=self.num_attention_heads,
+                # intermediate_size=self.intermediate_size,
+                # hidden_act=self.hidden_act,
+                # hidden_dropout_prob=self.hidden_dropout_prob,
+                # attention_probs_dropout_prob=self.attention_probs_dropout_prob,
+                n_positions=self.max_position_embeddings,
+                n_ctx=self.max_position_embeddings
+                # type_vocab_size=self.type_vocab_size,
+                # initializer_range=self.initializer_range
+            )
+
+            head_mask = ids_tensor([self.num_hidden_layers, self.num_attention_heads], 2)
+
+            return config, input_ids, input_mask, head_mask, token_type_ids, mc_token_ids, sequence_labels, token_labels, choice_labels
+
+        def check_loss_output(self, result):
+            self.parent.assertListEqual(
+                list(result["loss"].size()),
+                [])
+
+        def create_and_check_ctrl_model(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
+            model = CTRLModel(config=config)
+            model.eval()
+
+            model(input_ids, token_type_ids=token_type_ids, head_mask=head_mask)
+            model(input_ids, token_type_ids=token_type_ids)
+            sequence_output, presents = model(input_ids)
+
+            result = {
+                "sequence_output": sequence_output,
+                "presents": presents,
+            }
+            self.parent.assertListEqual(
+                list(result["sequence_output"].size()),
+                [self.batch_size, self.seq_length, self.hidden_size])
+            self.parent.assertEqual(len(result["presents"]), config.n_layer)
+
+        def create_and_check_lm_head_model(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
+            model = CTRLLMHeadModel(config)
+            model.eval()
+
+            loss, lm_logits, _ = model(input_ids, token_type_ids=token_type_ids, labels=input_ids)
+
+            result = {
+                "loss": loss,
+                "lm_logits": lm_logits
+            }
+            self.parent.assertListEqual(
+                list(result["loss"].size()),
+                [])
+            self.parent.assertListEqual(
+                list(result["lm_logits"].size()),
+                [self.batch_size, self.seq_length, self.vocab_size])
+
+
+        def prepare_config_and_inputs_for_common(self):
+            config_and_inputs = self.prepare_config_and_inputs()
+
+            (config, input_ids, input_mask, head_mask, token_type_ids,
+             mc_token_ids, sequence_labels, token_labels, choice_labels) = config_and_inputs
+
+            inputs_dict = {
+                'input_ids': input_ids,
+                'token_type_ids': token_type_ids,
+                'head_mask': head_mask
+            }
+
+            return config, inputs_dict
+
+    def setUp(self):
+        self.model_tester = CTRLModelTest.CTRLModelTester(self)
+        self.config_tester = ConfigTester(self, config_class=CTRLConfig, n_embd=37)
+
+    def test_config(self):
+        self.config_tester.run_common_tests()
+
+    def test_ctrl_model(self):
+        config_and_inputs = self.model_tester.prepare_config_and_inputs()
+        self.model_tester.create_and_check_ctrl_model(*config_and_inputs)
+
+    def test_ctrl_lm_head_model(self):
+        config_and_inputs = self.model_tester.prepare_config_and_inputs()
+        self.model_tester.create_and_check_lm_head_model(*config_and_inputs)
+
+    @pytest.mark.slow
+    def test_model_from_pretrained(self):
+        cache_dir = "/tmp/transformers_test/"
+        for model_name in list(CTRL_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
+            model = CTRLModel.from_pretrained(model_name, cache_dir=cache_dir)
+            shutil.rmtree(cache_dir)
+            self.assertIsNotNone(model)
+
+
+if __name__ == "__main__":
+    unittest.main()

transformers/tests/modeling_tf_common_test.py

@@ -71,6 +71,8 @@ class TFCommonTestCases:
             if not is_torch_available():
                 return
 
+            import torch
+            import numpy as np
             import transformers
 
             config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()
@@ -79,12 +81,23 @@ class TFCommonTestCases:
                 pt_model_class_name = model_class.__name__[2:]  # Skip the "TF" at the beggining
                 pt_model_class = getattr(transformers, pt_model_class_name)
 
+                config.output_hidden_states = True
                 tf_model = model_class(config)
                 pt_model = pt_model_class(config)
 
+                # Check we can load pt model in tf and vice-versa (architecture similar)
                 tf_model = transformers.load_pytorch_model_in_tf2_model(tf_model, pt_model, tf_inputs=inputs_dict)
                 pt_model = transformers.load_tf2_model_in_pytorch_model(pt_model, tf_model)
 
+                # Check predictions on first output (logits/hidden-states) are close enought given low-level computational differences
+                pt_model.eval()
+                pt_inputs_dict = dict((name, torch.from_numpy(key.numpy()).to(torch.long))
+                                      for name, key in inputs_dict.items())
+                with torch.no_grad():
+                    pto = pt_model(**pt_inputs_dict)
+                tfo = tf_model(inputs_dict)
+                max_diff = np.amax(np.abs(tfo[0].numpy() - pto[0].numpy()))
+                self.assertLessEqual(max_diff, 2e-2)
 
         def test_keyword_and_dict_args(self):
             config, inputs_dict = self.model_tester.prepare_config_and_inputs_for_common()

transformers/tests/modeling_tf_ctrl_test.py

@@ -0,0 +1,201 @@
+# coding=utf-8
+# Copyright 2018 The Google AI Language Team Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import unittest
+import shutil
+import pytest
+import sys
+
+from .modeling_tf_common_test import (TFCommonTestCases, ids_tensor)
+from .configuration_common_test import ConfigTester
+
+from transformers import CTRLConfig, is_tf_available
+
+if is_tf_available():
+    import tensorflow as tf
+    from transformers.modeling_tf_ctrl import (TFCTRLModel, TFCTRLLMHeadModel,
+                                                TF_CTRL_PRETRAINED_MODEL_ARCHIVE_MAP)
+else:
+    pytestmark = pytest.mark.skip("Require TensorFlow")
+
+
+class TFCTRLModelTest(TFCommonTestCases.TFCommonModelTester):
+
+    all_model_classes = (TFCTRLModel, TFCTRLLMHeadModel) if is_tf_available() else ()
+
+    class TFCTRLModelTester(object):
+
+        def __init__(self,
+                     parent,
+                     batch_size=13,
+                     seq_length=7,
+                     is_training=True,
+                     use_token_type_ids=True,
+                     use_input_mask=True,
+                     use_labels=True,
+                     use_mc_token_ids=True,
+                     vocab_size=99,
+                     hidden_size=32,
+                     num_hidden_layers=5,
+                     num_attention_heads=4,
+                     intermediate_size=37,
+                     hidden_act="gelu",
+                     hidden_dropout_prob=0.1,
+                     attention_probs_dropout_prob=0.1,
+                     max_position_embeddings=512,
+                     type_vocab_size=16,
+                     type_sequence_label_size=2,
+                     initializer_range=0.02,
+                     num_labels=3,
+                     num_choices=4,
+                     scope=None,
+                     ):
+            self.parent = parent
+            self.batch_size = batch_size
+            self.seq_length = seq_length
+            self.is_training = is_training
+            self.use_token_type_ids = use_token_type_ids
+            self.use_input_mask = use_input_mask
+            self.use_labels = use_labels
+            self.use_mc_token_ids = use_mc_token_ids
+            self.vocab_size = vocab_size
+            self.hidden_size = hidden_size
+            self.num_hidden_layers = num_hidden_layers
+            self.num_attention_heads = num_attention_heads
+            self.intermediate_size = intermediate_size
+            self.hidden_act = hidden_act
+            self.hidden_dropout_prob = hidden_dropout_prob
+            self.attention_probs_dropout_prob = attention_probs_dropout_prob
+            self.max_position_embeddings = max_position_embeddings
+            self.type_vocab_size = type_vocab_size
+            self.type_sequence_label_size = type_sequence_label_size
+            self.initializer_range = initializer_range
+            self.num_labels = num_labels
+            self.num_choices = num_choices
+            self.scope = scope
+
+        def prepare_config_and_inputs(self):
+            input_ids = ids_tensor([self.batch_size, self.seq_length], self.vocab_size)
+
+            input_mask = None
+            if self.use_input_mask:
+                input_mask = ids_tensor([self.batch_size, self.seq_length], vocab_size=2)
+
+            token_type_ids = None
+            if self.use_token_type_ids:
+                token_type_ids = ids_tensor([self.batch_size, self.seq_length], self.type_vocab_size)
+
+            mc_token_ids = None
+            if self.use_mc_token_ids:
+                mc_token_ids = ids_tensor([self.batch_size, self.num_choices], self.seq_length)
+
+            sequence_labels = None
+            token_labels = None
+            choice_labels = None
+            if self.use_labels:
+                sequence_labels = ids_tensor([self.batch_size], self.type_sequence_label_size)
+                token_labels = ids_tensor([self.batch_size, self.seq_length], self.num_labels)
+                choice_labels = ids_tensor([self.batch_size], self.num_choices)
+
+            config = CTRLConfig(
+                vocab_size_or_config_json_file=self.vocab_size,
+                n_embd=self.hidden_size,
+                n_layer=self.num_hidden_layers,
+                n_head=self.num_attention_heads,
+                # intermediate_size=self.intermediate_size,
+                # hidden_act=self.hidden_act,
+                # hidden_dropout_prob=self.hidden_dropout_prob,
+                # attention_probs_dropout_prob=self.attention_probs_dropout_prob,
+                n_positions=self.max_position_embeddings,
+                n_ctx=self.max_position_embeddings
+                # type_vocab_size=self.type_vocab_size,
+                # initializer_range=self.initializer_range
+            )
+
+            head_mask = ids_tensor([self.num_hidden_layers, self.num_attention_heads], 2)
+
+            return config, input_ids, input_mask, head_mask, token_type_ids, mc_token_ids, sequence_labels, token_labels, choice_labels
+
+        def create_and_check_ctrl_model(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
+            model = TFCTRLModel(config=config)
+            inputs = {'input_ids': input_ids,
+                      'attention_mask': input_mask,
+                      'token_type_ids': token_type_ids}
+            sequence_output = model(inputs)[0]
+
+            inputs = [input_ids, None, input_mask]  # None is the input for 'past'
+            sequence_output = model(inputs)[0]
+
+            sequence_output = model(input_ids)[0]
+
+            result = {
+                "sequence_output": sequence_output.numpy(),
+            }
+            self.parent.assertListEqual(
+                list(result["sequence_output"].shape),
+                [self.batch_size, self.seq_length, self.hidden_size])
+
+
+        def create_and_check_ctrl_lm_head(self, config, input_ids, input_mask, head_mask, token_type_ids, *args):
+            model = TFCTRLLMHeadModel(config=config)
+            inputs = {'input_ids': input_ids,
+                      'attention_mask': input_mask,
+                      'token_type_ids': token_type_ids}
+            prediction_scores = model(inputs)[0]
+            result = {
+                "prediction_scores": prediction_scores.numpy(),
+            }
+            self.parent.assertListEqual(
+                list(result["prediction_scores"].shape),
+                [self.batch_size, self.seq_length, self.vocab_size])
+
+        def prepare_config_and_inputs_for_common(self):
+            config_and_inputs = self.prepare_config_and_inputs()
+
+            (config, input_ids, input_mask, head_mask, token_type_ids,
+             mc_token_ids, sequence_labels, token_labels, choice_labels) = config_and_inputs
+
+            inputs_dict = {'input_ids': input_ids, 'token_type_ids': token_type_ids, 'attention_mask': input_mask}
+            return config, inputs_dict
+
+    def setUp(self):
+        self.model_tester = TFCTRLModelTest.TFCTRLModelTester(self)
+        self.config_tester = ConfigTester(self, config_class=CTRLConfig, n_embd=37)
+
+    def test_config(self):
+        self.config_tester.run_common_tests()
+
+    def test_ctrl_model(self):
+        config_and_inputs = self.model_tester.prepare_config_and_inputs()
+        self.model_tester.create_and_check_ctrl_model(*config_and_inputs)
+
+    def test_ctrl_lm_head(self):
+        config_and_inputs = self.model_tester.prepare_config_and_inputs()
+        self.model_tester.create_and_check_ctrl_lm_head(*config_and_inputs)
+
+    @pytest.mark.slow
+    def test_model_from_pretrained(self):
+        cache_dir = "/tmp/transformers_test/"
+        for model_name in list(TF_CTRL_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
+            model = TFCTRLModel.from_pretrained(model_name, cache_dir=cache_dir)
+            shutil.rmtree(cache_dir)
+            self.assertIsNotNone(model)
+
+if __name__ == "__main__":
+    unittest.main()
+

transformers/tests/modeling_tf_gpt2_test.py

@@ -222,7 +222,7 @@ class TFGPT2ModelTest(TFCommonTestCases.TFCommonModelTester):
     @pytest.mark.slow
     def test_model_from_pretrained(self):
         cache_dir = "/tmp/transformers_test/"
-        for model_name in list(TF_gpt2_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
+        for model_name in list(TF_GPT2_PRETRAINED_MODEL_ARCHIVE_MAP.keys())[:1]:
             model = TFGPT2Model.from_pretrained(model_name, cache_dir=cache_dir)
             shutil.rmtree(cache_dir)
             self.assertIsNotNone(model)

transformers/tests/tokenization_bert_test.py

@@ -131,8 +131,8 @@ class BertTokenizationTest(CommonTestCases.CommonTokenizerTester):
         text = tokenizer.encode("sequence builders")
         text_2 = tokenizer.encode("multi-sequence build")
 
-        encoded_sentence = tokenizer.add_special_tokens_single_sequence(text)
-        encoded_pair = tokenizer.add_special_tokens_sequence_pair(text, text_2)
+        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
+        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)
 
         assert encoded_sentence == [101] + text + [102]
         assert encoded_pair == [101] + text + [102] + text_2 + [102]

transformers/tests/tokenization_ctrl_test.py

@@ -0,0 +1,69 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and HuggingFace Inc. team.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import os
+import unittest
+import json
+from io import open
+
+from transformers.tokenization_ctrl import CTRLTokenizer, VOCAB_FILES_NAMES
+
+from .tokenization_tests_commons import CommonTestCases
+
+class CTRLTokenizationTest(CommonTestCases.CommonTokenizerTester):
+
+    tokenizer_class = CTRLTokenizer
+
+    def setUp(self):
+        super(CTRLTokenizationTest, self).setUp()
+
+        # Adapted from Sennrich et al. 2015 and https://github.com/rsennrich/subword-nmt
+        vocab = ['adapt', 're@@', 'a@@', 'apt', 'c@@', 't', '<unk>']
+        vocab_tokens = dict(zip(vocab, range(len(vocab))))
+        merges = ["#version: 0.2", 'a p', 'ap t</w>', 'r e', 'a d', 'ad apt</w>', '']
+        self.special_tokens_map = {"unk_token": "<unk>"}
+
+        self.vocab_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['vocab_file'])
+        self.merges_file = os.path.join(self.tmpdirname, VOCAB_FILES_NAMES['merges_file'])
+        with open(self.vocab_file, "w", encoding="utf-8") as fp:
+            fp.write(json.dumps(vocab_tokens) + "\n")
+        with open(self.merges_file, "w", encoding="utf-8") as fp:
+            fp.write("\n".join(merges))
+
+    def get_tokenizer(self, **kwargs):
+        kwargs.update(self.special_tokens_map)
+        return CTRLTokenizer.from_pretrained(self.tmpdirname, **kwargs)
+
+    def get_input_output_texts(self):
+        input_text = u"adapt react readapt apt"
+        output_text = u"adapt react readapt apt"
+        return input_text, output_text
+
+    def test_full_tokenizer(self):
+        tokenizer = CTRLTokenizer(self.vocab_file, self.merges_file, **self.special_tokens_map)
+        text = "adapt react readapt apt"
+        bpe_tokens = 'adapt re@@ a@@ c@@ t re@@ adapt apt'.split()
+        tokens = tokenizer.tokenize(text)
+        self.assertListEqual(tokens, bpe_tokens)
+
+        input_tokens = tokens + [tokenizer.unk_token]
+
+        input_bpe_tokens = [0, 1, 2, 4, 5, 1, 0, 3, 6]
+        self.assertListEqual(
+            tokenizer.convert_tokens_to_ids(input_tokens), input_bpe_tokens)
+
+
+if __name__ == '__main__':
+    unittest.main()

transformers/tests/tokenization_distilbert_test.py

@@ -36,8 +36,8 @@ class DistilBertTokenizationTest(BertTokenizationTest):
         text = tokenizer.encode("sequence builders")
         text_2 = tokenizer.encode("multi-sequence build")
 
-        encoded_sentence = tokenizer.add_special_tokens_single_sequence(text)
-        encoded_pair = tokenizer.add_special_tokens_sequence_pair(text, text_2)
+        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
+        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)
 
         assert encoded_sentence == [tokenizer.cls_token_id] + text + [tokenizer.sep_token_id]
         assert encoded_pair == [tokenizer.cls_token_id] + text + [tokenizer.sep_token_id] + \

transformers/tests/tokenization_roberta_test.py

@@ -87,8 +87,8 @@ class RobertaTokenizationTest(CommonTestCases.CommonTokenizerTester):
         encoded_text_from_decode = tokenizer.encode("sequence builders", add_special_tokens=True)
         encoded_pair_from_decode = tokenizer.encode("sequence builders", "multi-sequence build", add_special_tokens=True)
 
-        encoded_sentence = tokenizer.add_special_tokens_single_sequence(text)
-        encoded_pair = tokenizer.add_special_tokens_sequence_pair(text, text_2)
+        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
+        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)
 
         assert encoded_sentence == encoded_text_from_decode
         assert encoded_pair == encoded_pair_from_decode

transformers/tests/tokenization_tests_commons.py

@@ -193,12 +193,12 @@ class CommonTestCases:
 
             tokenizer = self.get_tokenizer()
 
-            if tokenizer.add_special_tokens_sequence_pair.__qualname__.split('.')[0] != "PreTrainedTokenizer":
+            if tokenizer.build_inputs_with_special_tokens.__qualname__.split('.')[0] != "PreTrainedTokenizer":
                 seq_0 = "Test this method."
                 seq_1 = "With these inputs."
                 information = tokenizer.encode_plus(seq_0, seq_1, add_special_tokens=True)
                 sequences, mask = information["input_ids"], information["token_type_ids"]
-                assert len(sequences) == len(mask)
+                self.assertEqual(len(sequences), len(mask))
 
         def test_number_of_added_tokens(self):
             tokenizer = self.get_tokenizer()
@@ -211,7 +211,7 @@ class CommonTestCases:
 
             # Method is implemented (e.g. not GPT-2)
             if len(attached_sequences) != 2:
-                assert tokenizer.num_added_tokens(pair=True) == len(attached_sequences) - len(sequences)
+                self.assertEqual(tokenizer.num_added_tokens(pair=True), len(attached_sequences) - len(sequences))
 
         def test_maximum_encoding_length_single_input(self):
             tokenizer = self.get_tokenizer()
@@ -227,10 +227,10 @@ class CommonTestCases:
             truncated_sequence = information["input_ids"]
             overflowing_tokens = information["overflowing_tokens"]
 
-            assert len(overflowing_tokens) == 2 + stride
-            assert overflowing_tokens == sequence[-(2 + stride):]
-            assert len(truncated_sequence) == total_length - 2
-            assert truncated_sequence == tokenizer.add_special_tokens_single_sequence(sequence[:-2])
+            self.assertEqual(len(overflowing_tokens), 2 + stride)
+            self.assertEqual(overflowing_tokens, sequence[-(2 + stride):])
+            self.assertEqual(len(truncated_sequence), total_length - 2)
+            self.assertEqual(truncated_sequence, tokenizer.build_inputs_with_special_tokens(sequence[:-2]))
 
         def test_maximum_encoding_length_pair_input(self):
             tokenizer = self.get_tokenizer()
@@ -243,26 +243,26 @@ class CommonTestCases:
             sequence_1_no_special_tokens = tokenizer.encode(seq_1)
 
             sequence = tokenizer.encode(seq_0, seq_1, add_special_tokens=True)
-            truncated_second_sequence = tokenizer.add_special_tokens_sequence_pair(
+            truncated_second_sequence = tokenizer.build_inputs_with_special_tokens(
                 tokenizer.encode(seq_0),
                 tokenizer.encode(seq_1)[:-2]
             )
 
             information = tokenizer.encode_plus(seq_0, seq_1, max_length=len(sequence) - 2, add_special_tokens=True,
-                                                stride=stride, truncate_first_sequence=False)
+                                                stride=stride, truncation_strategy='only_second')
             information_first_truncated = tokenizer.encode_plus(seq_0, seq_1, max_length=len(sequence) - 2,
                                                                 add_special_tokens=True, stride=stride,
-                                                                truncate_first_sequence=True)
+                                                                truncation_strategy='only_first')
 
             truncated_sequence = information["input_ids"]
             overflowing_tokens = information["overflowing_tokens"]
             overflowing_tokens_first_truncated = information_first_truncated["overflowing_tokens"]
 
-            assert len(overflowing_tokens) == 2 + stride
-            assert overflowing_tokens == sequence_1_no_special_tokens[-(2 + stride):]
-            assert overflowing_tokens_first_truncated == sequence_0_no_special_tokens[-(2 + stride):]
-            assert len(truncated_sequence) == len(sequence) - 2
-            assert truncated_sequence == truncated_second_sequence
+            self.assertEqual(len(overflowing_tokens), 2 + stride)
+            self.assertEqual(overflowing_tokens, sequence_1_no_special_tokens[-(2 + stride):])
+            self.assertEqual(overflowing_tokens_first_truncated, sequence_0_no_special_tokens[-(2 + stride):])
+            self.assertEqual(len(truncated_sequence), len(sequence) - 2)
+            self.assertEqual(truncated_sequence, truncated_second_sequence)
 
         def test_encode_input_type(self):
             tokenizer = self.get_tokenizer()
@@ -273,5 +273,43 @@ class CommonTestCases:
             input_ids = tokenizer.convert_tokens_to_ids(tokens)
             formatted_input = tokenizer.encode(sequence, add_special_tokens=True)
 
-            assert tokenizer.encode(tokens, add_special_tokens=True) == formatted_input
-            assert tokenizer.encode(input_ids, add_special_tokens=True) == formatted_input
+            self.assertEqual(tokenizer.encode(tokens, add_special_tokens=True), formatted_input)
+            self.assertEqual(tokenizer.encode(input_ids, add_special_tokens=True), formatted_input)
+
+        def test_special_tokens_mask(self):
+            tokenizer = self.get_tokenizer()
+
+            sequence_0 = "Encode this."
+            sequence_1 = "This one too please."
+
+            # Testing single inputs
+            encoded_sequence = tokenizer.encode(sequence_0)
+            encoded_sequence_dict = tokenizer.encode_plus(sequence_0, add_special_tokens=True)
+            encoded_sequence_w_special = encoded_sequence_dict["input_ids"]
+            special_tokens_mask = encoded_sequence_dict["special_tokens_mask"]
+            self.assertEqual(len(special_tokens_mask), len(encoded_sequence_w_special))
+
+            filtered_sequence = [(x if not special_tokens_mask[i] else None) for i, x in enumerate(encoded_sequence_w_special)]
+            filtered_sequence = [x for x in filtered_sequence if x is not None]
+            self.assertEqual(encoded_sequence, filtered_sequence)
+
+            # Testing inputs pairs
+            encoded_sequence = tokenizer.encode(sequence_0) + tokenizer.encode(sequence_1)
+            encoded_sequence_dict = tokenizer.encode_plus(sequence_0, sequence_1, add_special_tokens=True)
+            encoded_sequence_w_special = encoded_sequence_dict["input_ids"]
+            special_tokens_mask = encoded_sequence_dict["special_tokens_mask"]
+            self.assertEqual(len(special_tokens_mask), len(encoded_sequence_w_special))
+
+            filtered_sequence = [(x if not special_tokens_mask[i] else None) for i, x in enumerate(encoded_sequence_w_special)]
+            filtered_sequence = [x for x in filtered_sequence if x is not None]
+            self.assertEqual(encoded_sequence, filtered_sequence)
+
+            # Testing with already existing special tokens
+            if tokenizer.cls_token_id == tokenizer.unk_token_id and tokenizer.cls_token_id == tokenizer.unk_token_id:
+                tokenizer.add_special_tokens({'cls_token': '</s>', 'sep_token': '<s>'})
+            encoded_sequence_dict = tokenizer.encode_plus(sequence_0, add_special_tokens=True)
+            encoded_sequence_w_special = encoded_sequence_dict["input_ids"]
+            special_tokens_mask_orig = encoded_sequence_dict["special_tokens_mask"]
+            special_tokens_mask = tokenizer.get_special_tokens_mask(encoded_sequence_w_special, already_has_special_tokens=True)
+            self.assertEqual(len(special_tokens_mask), len(encoded_sequence_w_special))
+            self.assertEqual(special_tokens_mask_orig, special_tokens_mask)

transformers/tests/tokenization_xlm_test.py

@@ -72,8 +72,8 @@ class XLMTokenizationTest(CommonTestCases.CommonTokenizerTester):
         text = tokenizer.encode("sequence builders")
         text_2 = tokenizer.encode("multi-sequence build")
 
-        encoded_sentence = tokenizer.add_special_tokens_single_sequence(text)
-        encoded_pair = tokenizer.add_special_tokens_sequence_pair(text, text_2)
+        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
+        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)
 
         assert encoded_sentence == [1] + text + [1]
         assert encoded_pair == [1] + text + [1] + text_2 + [1]

transformers/tests/tokenization_xlnet_test.py

@@ -95,8 +95,8 @@ class XLNetTokenizationTest(CommonTestCases.CommonTokenizerTester):
         text = tokenizer.encode("sequence builders")
         text_2 = tokenizer.encode("multi-sequence build")
 
-        encoded_sentence = tokenizer.add_special_tokens_single_sequence(text)
-        encoded_pair = tokenizer.add_special_tokens_sequence_pair(text, text_2)
+        encoded_sentence = tokenizer.build_inputs_with_special_tokens(text)
+        encoded_pair = tokenizer.build_inputs_with_special_tokens(text, text_2)
 
         assert encoded_sentence == text + [4, 3]
         assert encoded_pair == text + [4] + text_2 + [4, 3]

transformers/tokenization_auto.py

@@ -21,6 +21,7 @@ import logging
 from .tokenization_bert import BertTokenizer
 from .tokenization_openai import OpenAIGPTTokenizer
 from .tokenization_gpt2 import GPT2Tokenizer
+from .tokenization_ctrl import CTRLTokenizer
 from .tokenization_transfo_xl import TransfoXLTokenizer
 from .tokenization_xlnet import XLNetTokenizer
 from .tokenization_xlm import XLMTokenizer
@@ -45,6 +46,7 @@ class AutoTokenizer(object):
             - contains `bert`: BertTokenizer (Bert model)
             - contains `openai-gpt`: OpenAIGPTTokenizer (OpenAI GPT model)
             - contains `gpt2`: GPT2Tokenizer (OpenAI GPT-2 model)
+            - contains `ctrl`: CTRLTokenizer (Salesforce CTRL model)
             - contains `transfo-xl`: TransfoXLTokenizer (Transformer-XL model)
             - contains `xlnet`: XLNetTokenizer (XLNet model)
             - contains `xlm`: XLMTokenizer (XLM model)
@@ -67,6 +69,7 @@ class AutoTokenizer(object):
             - contains `bert`: BertTokenizer (Bert model)
             - contains `openai-gpt`: OpenAIGPTTokenizer (OpenAI GPT model)
             - contains `gpt2`: GPT2Tokenizer (OpenAI GPT-2 model)
+            - contains `ctrl`: CTRLTokenizer (Salesforce CTRL model)
             - contains `transfo-xl`: TransfoXLTokenizer (Transformer-XL model)
             - contains `xlnet`: XLNetTokenizer (XLNet model)
             - contains `xlm`: XLMTokenizer (XLM model)
@@ -114,7 +117,8 @@ class AutoTokenizer(object):
             return XLNetTokenizer.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
         elif 'xlm' in pretrained_model_name_or_path:
             return XLMTokenizer.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
-
+        elif 'ctrl' in pretrained_model_name_or_path:
+            return CTRLTokenizer.from_pretrained(pretrained_model_name_or_path, *inputs, **kwargs)
         raise ValueError("Unrecognized model identifier in {}. Should contains one of "
                          "'bert', 'openai-gpt', 'gpt2', 'transfo-xl', 'xlnet', "
-                         "'xlm', 'roberta'".format(pretrained_model_name_or_path))
+                         "'xlm', 'roberta', 'ctrl'".format(pretrained_model_name_or_path))

transformers/tokenization_bert.py

@@ -187,33 +187,59 @@ class BertTokenizer(PreTrainedTokenizer):
         out_string = ' '.join(tokens).replace(' ##', '').strip()
         return out_string
 
-    def add_special_tokens_single_sequence(self, token_ids):
+    def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
         """
-        Adds special tokens to the a sequence for sequence classification tasks.
-        A BERT sequence has the following format: [CLS] X [SEP]
+        Build model inputs from a sequence or a pair of sequence for sequence classification tasks
+        by concatenating and adding special tokens.
+        A BERT sequence has the following format:
+            single sequence: [CLS] X [SEP]
+            pair of sequences: [CLS] A [SEP] B [SEP]
         """
-        return [self.cls_token_id] + token_ids + [self.sep_token_id]
-
-    def add_special_tokens_sequence_pair(self, token_ids_0, token_ids_1):
-        """
-        Adds special tokens to a sequence pair for sequence classification tasks.
-        A BERT sequence pair has the following format: [CLS] A [SEP] B [SEP]
-        """
-        sep = [self.sep_token_id]
+        if token_ids_1 is None:
+            return [self.cls_token_id] + token_ids_0 + [self.sep_token_id]
         cls = [self.cls_token_id]
-
+        sep = [self.sep_token_id]
         return cls + token_ids_0 + sep + token_ids_1 + sep
 
-    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
+    def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+                for sequence pairs
+            already_has_special_tokens: (default False) Set to True if the token list is already formated with
+                special tokens for the model
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+
+        if already_has_special_tokens:
+            if token_ids_1 is not None:
+                raise ValueError("You should not supply a second sequence if the provided sequence of "
+                                 "ids is already formated with special tokens for the model.")
+            return list(map(lambda x: 1 if x in [self.sep_token_id, self.cls_token_id] else 0, token_ids_0))
+
+        if token_ids_1 is not None:
+            return [1] + ([0] * len(token_ids_0)) + [1] + ([0] * len(token_ids_1)) + [1]
+        return [1] + ([0] * len(token_ids_0)) + [1]
+
+    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
         """
         Creates a mask from the two sequences passed to be used in a sequence-pair classification task.
         A BERT sequence pair mask has the following format:
         0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
         | first sequence    | second sequence
+
+        if token_ids_1 is None, only returns the first portion of the mask (0's).
         """
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
-
+        if token_ids_1 is None:
+            return len(cls + token_ids_0 + sep) * [0]
         return len(cls + token_ids_0 + sep) * [0] + len(token_ids_1 + sep) * [1]
 
     def save_vocabulary(self, vocab_path):

transformers/tokenization_ctrl.py

@@ -0,0 +1,239 @@
+# coding=utf-8
+# Copyright 2018 Salesforce and The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Tokenization classes for Salesforce CTRL."""
+from __future__ import (absolute_import, division, print_function,
+                        unicode_literals)
+
+import json
+import logging
+import os
+import regex as re
+from io import open
+
+from .tokenization_bert import BasicTokenizer
+
+from .tokenization_utils import PreTrainedTokenizer
+
+logger = logging.getLogger(__name__)
+
+VOCAB_FILES_NAMES = {
+    'vocab_file': 'vocab.json',
+    'merges_file': 'merges.txt',
+}
+
+PRETRAINED_VOCAB_FILES_MAP = {
+    'vocab_file':
+    {
+        'ctrl': "https://raw.githubusercontent.com/salesforce/ctrl/master/ctrl-vocab.json",
+    },
+    'merges_file':
+    {
+        'ctrl': "https://raw.githubusercontent.com/salesforce/ctrl/master/ctrl-merges.txt",
+    },
+}
+
+PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
+    'ctrl': 256,
+}
+
+def text_standardize(text):
+    """
+    fixes some issues the spacy tokenizer had on books corpus
+    also does some whitespace standardization
+    """
+    text = text.replace('—', '-')
+    text = text.replace('–', '-')
+    text = text.replace('―', '-')
+    text = text.replace('…', '...')
+    text = text.replace('´', "'")
+    text = re.sub(r'''(-+|~+|!+|"+|;+|\?+|\++|,+|\)+|\(+|\\+|\/+|\*+|\[+|\]+|}+|{+|\|+|_+)''', r' \1 ', text)
+    text = re.sub(r'\s*\n\s*', ' \n ', text)
+    text = re.sub(r'[^\S\n]+', ' ', text)
+    return text.strip()
+
+
+def get_pairs(word):
+    """Return set of symbol pairs in a word.
+
+    Word is represented as tuple of symbols (symbols being variable-length strings).
+    """
+    # pairs = []
+    # prev_char = word[0]
+    # for i, char in enumerate(word[1:]):
+    #     #_i = i + 1
+    #     #if word[_i+1:] == tuple('</w>'):
+    #     #    pairs.append((prev_char, char+'</w>'))
+    #     #    break
+    #     #else:
+    #     if True:
+    #         pairs.append((prev_char, char))
+    #         prev_char = char
+
+    pairs = set()
+    prev_char = word[0]
+    for char in word[1:]:
+        pairs.add((prev_char, char))
+        prev_char = char
+
+    pairs = set(pairs)
+    return pairs
+
+class CTRLTokenizer(PreTrainedTokenizer):
+    """
+    CTRL BPE tokenizer. Peculiarities:
+        - Byte-level Byte-Pair-Encoding
+        - Requires a space to start the input string => the encoding methods should be called with the
+          ``add_prefix_space`` flag set to ``True``.
+          Otherwise, this tokenizer ``encode`` and ``decode`` method will not conserve
+          the absence of a space at the beginning of a string: `tokenizer.decode(tokenizer.encode("Hello")) = " Hello"`
+    """
+    vocab_files_names = VOCAB_FILES_NAMES
+    pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
+    max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
+
+    def __init__(self, vocab_file, merges_file, unk_token="<unk>", **kwargs):
+        super(CTRLTokenizer, self).__init__(unk_token=unk_token, **kwargs)
+        self.max_len_single_sentence = self.max_len # no default special tokens - you can update this value if you add special tokens
+        self.max_len_sentences_pair = self.max_len # no default special tokens - you can update this value if you add special tokens
+
+        try:
+            import ftfy
+            from spacy.lang.en import English
+            _nlp = English()
+            self.nlp = _nlp.Defaults.create_tokenizer(_nlp)
+            self.fix_text = ftfy.fix_text
+        except ImportError:
+            logger.warning("ftfy or spacy is not installed using BERT BasicTokenizer instead of SpaCy & ftfy.")
+            self.nlp = BasicTokenizer(do_lower_case=True)
+            self.fix_text = None
+
+        self.encoder = json.load(open(vocab_file, encoding="utf-8"))
+        self.decoder = {v:k for k,v in self.encoder.items()}
+        merges = open(merges_file, encoding='utf-8').read().split('\n')[1:-1]
+        merges = [tuple(merge.split()) for merge in merges]
+        self.bpe_ranks = dict(zip(merges, range(len(merges))))
+        self.cache = {}
+
+    @property
+    def vocab_size(self):
+        return len(self.encoder)
+
+    def bpe(self, token):
+        if token in self.cache:
+            return self.cache[token]
+        word = tuple(token)
+        word = tuple(list(word[:-1]) + [word[-1]+'</w>'])
+        pairs = get_pairs(word)
+
+        if not pairs:
+            return token
+
+        while True:
+            bigram = min(pairs, key = lambda pair: self.bpe_ranks.get(pair, float('inf')))
+            if bigram not in self.bpe_ranks:
+                break
+            first, second = bigram
+            new_word = []
+            i = 0
+            while i < len(word):
+                try:
+                    j = word.index(first, i)
+                    new_word.extend(word[i:j])
+                    i = j
+                except:
+                    new_word.extend(word[i:])
+                    break
+
+                if word[i] == first and i < len(word)-1 and word[i+1] == second:
+                    new_word.append(first+second)
+                    i += 2
+                else:
+                    new_word.append(word[i])
+                    i += 1
+            new_word = tuple(new_word)
+            word = new_word
+            if len(word) == 1:
+                break
+            else:
+                pairs = get_pairs(word)
+        word = '@@ '.join(word)
+        word = word[:-4]
+        self.cache[token] = word
+        return word
+
+    def _tokenize(self, text):
+        """ Tokenize a string.
+        """
+        split_tokens = []
+        if self.fix_text is None:
+            # Using BERT's BasicTokenizer
+            text = self.nlp.tokenize(text)
+            for token in text:
+                split_tokens.extend([t for t in self.bpe(token).split(' ')])
+        else:
+            # Using SpaCy & ftfy (original tokenization process of OpenAI GPT)
+            text = self.nlp(text_standardize(self.fix_text(text)))
+            for token in text:
+                split_tokens.extend([t for t in self.bpe(token.text.lower()).split(' ')])
+        # for token in text.split():
+        #     if sys.version_info[0] == 2:
+        #         token = ''.join(self.byte_encoder[ord(b)] for b in token) # Maps all our bytes to unicode strings, avoiding controle tokens of the BPE (spaces in our case)
+        #     else:
+        #         token = ''.join(self.byte_encoder[b] for b in token.encode('utf-8')) # Maps all our bytes to unicode strings, avoiding controle tokens of the BPE (spaces in our case)
+        #     bpe_tokens.extend(bpe_token for bpe_token in self.bpe(token).split(' '))
+        return split_tokens
+
+    def _convert_token_to_id(self, token):
+        """ Converts a token (str/unicode) in an id using the vocab. """
+        return self.encoder.get(token, self.encoder.get(self.unk_token))
+
+    def _convert_id_to_token(self, index):
+        """Converts an index (integer) in a token (string/unicode) using the vocab."""
+        return self.decoder.get(index, self.unk_token)
+
+    def convert_tokens_to_string(self, tokens):
+        """ Converts a sequence of tokens (string) in a single string. """
+        out_string = ' '.join(tokens).replace('@@ ', '').strip()
+        return out_string
+
+    def save_vocabulary(self, save_directory):
+        """Save the tokenizer vocabulary and merge files to a directory."""
+        if not os.path.isdir(save_directory):
+            logger.error("Vocabulary path ({}) should be a directory".format(save_directory))
+            return
+        vocab_file = os.path.join(save_directory, VOCAB_FILES_NAMES['vocab_file'])
+        merge_file = os.path.join(save_directory, VOCAB_FILES_NAMES['merges_file'])
+
+        with open(vocab_file, 'w', encoding='utf-8') as f:
+            f.write(json.dumps(self.encoder, ensure_ascii=False))
+
+        index = 0
+        with open(merge_file, "w", encoding="utf-8") as writer:
+            writer.write(u'#version: 0.2\n')
+            for bpe_tokens, token_index in sorted(self.bpe_ranks.items(), key=lambda kv: kv[1]):
+                if index != token_index:
+                    logger.warning("Saving vocabulary to {}: BPE merge indices are not consecutive."
+                                   " Please check that the tokenizer is not corrupted!".format(merge_file))
+                    index = token_index
+                writer.write(' '.join(bpe_tokens) + u'\n')
+                index += 1
+
+        return vocab_file, merge_file
+
+    # def decode(self, token_ids, skip_special_tokens=False, clean_up_tokenization_spaces=True):
+    #     filtered_tokens = ' '.join(self.convert_ids_to_tokens(token_ids, skip_special_tokens=skip_special_tokens))
+    #     tokens_generated_so_far = re.sub('(@@ )', '', string=filtered_tokens)
+    #     tokens_generated_so_far = re.sub('(@@ ?$)', '', string=tokens_generated_so_far)
+    #     return ''.join(tokens_generated_so_far)

transformers/tokenization_gpt2.py

@@ -46,12 +46,14 @@ PRETRAINED_VOCAB_FILES_MAP = {
         'gpt2': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-vocab.json",
         'gpt2-medium': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-medium-vocab.json",
         'gpt2-large': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-vocab.json",
+        'distilgpt2': "https://s3.amazonaws.com/models.huggingface.co/bert/distilgpt2-vocab.json",
     },
     'merges_file':
     {
         'gpt2': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-merges.txt",
         'gpt2-medium': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-medium-merges.txt",
         'gpt2-large': "https://s3.amazonaws.com/models.huggingface.co/bert/gpt2-large-merges.txt",
+        'distilgpt2': "https://s3.amazonaws.com/models.huggingface.co/bert/distilgpt2-merges.txt",
     },
 }
 
@@ -59,6 +61,7 @@ PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
     'gpt2': 1024,
     'gpt2-medium': 1024,
     'gpt2-large': 1024,
+    'distilgpt2': 1024,
 }
 
 @lru_cache()
@@ -101,9 +104,10 @@ class GPT2Tokenizer(PreTrainedTokenizer):
     """
     GPT-2 BPE tokenizer. Peculiarities:
         - Byte-level Byte-Pair-Encoding
-        - Requires a space to start the input string => will add a space is there isn't.
-          As a consequence, this tokenizer `encode` and `decode` method will not conserve
-          the absence of a space at the beginning of a string: `tokenizer.decode(tokenizer.encode("Hello")) = " Hello"
+        - Requires a space to start the input string => the encoding methods should be called with the
+          ``add_prefix_space`` flag set to ``True``.
+          Otherwise, this tokenizer ``encode`` and ``decode`` method will not conserve
+          the absence of a space at the beginning of a string: `tokenizer.decode(tokenizer.encode("Hello")) = " Hello"`
     """
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP

transformers/tokenization_roberta.py

@@ -66,9 +66,10 @@ class RobertaTokenizer(GPT2Tokenizer):
     """
     RoBERTa BPE tokenizer, derived from the GPT-2 tokenizer. Peculiarities:
         - Byte-level Byte-Pair-Encoding
-        - Requires a space to start the input string => will add a space is there isn't.
-          As a consequence, this tokenizer `encode` and `decode` method will not conserve
-          the absence of a space at the beginning of a string: `tokenizer.decode(tokenizer.encode("Hello")) = " Hello"
+        - Requires a space to start the input string => the encoding methods should be called with the
+          ``add_prefix_space`` flag set to ``True``.
+          Otherwise, this tokenizer ``encode`` and ``decode`` method will not conserve
+          the absence of a space at the beginning of a string: `tokenizer.decode(tokenizer.encode("Hello")) = " Hello"`
     """
     vocab_files_names = VOCAB_FILES_NAMES
     pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
@@ -80,31 +81,60 @@ class RobertaTokenizer(GPT2Tokenizer):
                                                bos_token=bos_token, eos_token=eos_token, unk_token=unk_token,
                                                sep_token=sep_token, cls_token=cls_token, pad_token=pad_token,
                                                mask_token=mask_token, **kwargs)
+        self.max_len_single_sentence = self.max_len - 2  # take into account special tokens
+        self.max_len_sentences_pair = self.max_len - 4  # take into account special tokens
 
-    def add_special_tokens_single_sequence(self, token_ids):
+    def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
         """
-        Adds special tokens to a sequence for sequence classification tasks.
-        A RoBERTa sequence has the following format: <s> X </s>
+        Build model inputs from a sequence or a pair of sequence for sequence classification tasks
+        by concatenating and adding special tokens.
+        A RoBERTa sequence has the following format:
+            single sequence: <s> X </s>
+            pair of sequences: <s> A </s></s> B </s>
         """
-        return [self.cls_token_id] + token_ids + [self.sep_token_id]
-
-    def add_special_tokens_sequence_pair(self, token_ids_0, token_ids_1):
-        """
-        Adds special tokens to a sequence pair for sequence classification tasks.
-        A RoBERTa sequence pair has the following format: <s> A </s></s> B </s>
-        """
-        sep = [self.sep_token_id]
+        if token_ids_1 is None:
+            return [self.cls_token_id] + token_ids_0 + [self.sep_token_id]
         cls = [self.cls_token_id]
+        sep = [self.sep_token_id]
         return cls + token_ids_0 + sep + sep + token_ids_1 + sep
 
-    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
+    def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+                for sequence pairs
+            already_has_special_tokens: (default False) Set to True if the token list is already formated with
+                special tokens for the model
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+        if already_has_special_tokens:
+            if token_ids_1 is not None:
+                raise ValueError("You should not supply a second sequence if the provided sequence of "
+                                 "ids is already formated with special tokens for the model.")
+            return list(map(lambda x: 1 if x in [self.sep_token_id, self.cls_token_id] else 0, token_ids_0))
+
+        if token_ids_1 is None:
+            return [1] + ([0] * len(token_ids_0)) + [1]
+        return [1] + ([0] * len(token_ids_0)) + [1, 1] + ([0] * len(token_ids_1)) + [1]
+
+    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
         """
         Creates a mask from the two sequences passed to be used in a sequence-pair classification task.
         A RoBERTa sequence pair mask has the following format:
         0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
         | first sequence    | second sequence
+
+        if token_ids_1 is None, only returns the first portion of the mask (0's).
         """
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
 
-        return len(cls + token_ids_0 + sep + sep) * [0] + len(token_ids_1 + sep) * [1]
+        if token_ids_1 is None:
+            return len(cls + token_ids_0 + sep) * [0]
+        return len(cls + token_ids_0 + sep + sep) * [0] + len(token_ids_1 + sep) * [1]

transformers/tokenization_utils.py

@@ -430,7 +430,7 @@ class PreTrainedTokenizer(object):
                 - tokenizer instantiation positional and keywords inputs (e.g. do_lower_case for Bert).
 
             This won't save modifications other than (added tokens and special token mapping) you may have
-            applied to the tokenizer after the instantion (e.g. modifying tokenizer.do_lower_case after creation).
+            applied to the tokenizer after the instantiation (e.g. modifying tokenizer.do_lower_case after creation).
 
             This method make sure the full tokenizer can then be re-loaded using the :func:`~transformers.PreTrainedTokenizer.from_pretrained` class method.
         """
@@ -512,7 +512,8 @@ class PreTrainedTokenizer(object):
         for token in new_tokens:
             assert isinstance(token, str) or (six.PY2 and isinstance(token, unicode))
             if token != self.unk_token and \
-                    self.convert_tokens_to_ids(token) == self.convert_tokens_to_ids(self.unk_token):
+                    self.convert_tokens_to_ids(token) == self.convert_tokens_to_ids(self.unk_token) and \
+                    token not in to_add_tokens:
                 to_add_tokens.append(token)
                 logger.info("Adding %s to the vocabulary", token)
 
@@ -538,15 +539,9 @@ class PreTrainedTokenizer(object):
         Returns:
             Number of tokens added to sequences
         """
-
-        if pair:
-            initial_tokens_len = len(self.encode("This is a sequence") + self.encode("This is another"))
-            final_tokens_len = len(self.encode("This is a sequence", "This is another", add_special_tokens=True))
-        else:
-            initial_tokens_len = len(self.encode("This is a sequence"))
-            final_tokens_len = len(self.encode("This is a sequence", add_special_tokens=True))
-
-        return final_tokens_len - initial_tokens_len
+        token_ids_0 = []
+        token_ids_1 = []
+        return len(self.build_inputs_with_special_tokens(token_ids_0, token_ids_1 if pair else None))
 
     def add_special_tokens(self, special_tokens_dict):
         """
@@ -698,7 +693,7 @@ class PreTrainedTokenizer(object):
                 add_special_tokens=False,
                 max_length=None,
                 stride=0,
-                truncate_first_sequence=True,
+                truncation_strategy='longest_first',
                 return_tensors=None,
                 **kwargs):
         """
@@ -718,9 +713,13 @@ class PreTrainedTokenizer(object):
             max_length: if set to a number, will limit the total sequence returned so that it has a maximum length.
                 If there are overflowing tokens, those will be added to the returned dictionary
             stride: if set to a number along with max_length, the overflowing tokens returned will contain some tokens
-                from the main sequence returned. The value of this argument defined the number of additional tokens.
-            truncate_first_sequence: if there is a specified max_length, this flag will choose which sequence
-                will be truncated.
+                from the main sequence returned. The value of this argument defines the number of additional tokens.
+            truncation_strategy: string selected in the following options:
+                - 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
+                    starting from the longest one at each token (when there is a pair of input sequences)
+                - 'only_first': Only truncate the first sequence
+                - 'only_second': Only truncate the second sequence
+                - 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
             return_tensors: (optional) can be set to 'tf' or 'pt' to return respectively TensorFlow tf.constant
                 or PyTorch torch.Tensor instead of a list of python integers.
             **kwargs: passed to the `self.tokenize()` method
@@ -730,7 +729,7 @@ class PreTrainedTokenizer(object):
                                           max_length=max_length,
                                           add_special_tokens=add_special_tokens,
                                           stride=stride,
-                                          truncate_first_sequence=truncate_first_sequence,
+                                          truncation_strategy=truncation_strategy,
                                           return_tensors=return_tensors,
                                           **kwargs)
 
@@ -742,7 +741,7 @@ class PreTrainedTokenizer(object):
                     add_special_tokens=False,
                     max_length=None,
                     stride=0,
-                    truncate_first_sequence=True,
+                    truncation_strategy='longest_first',
                     return_tensors=None,
                     **kwargs):
         """
@@ -761,9 +760,13 @@ class PreTrainedTokenizer(object):
             max_length: if set to a number, will limit the total sequence returned so that it has a maximum length.
                 If there are overflowing tokens, those will be added to the returned dictionary
             stride: if set to a number along with max_length, the overflowing tokens returned will contain some tokens
-                from the main sequence returned. The value of this argument defined the number of additional tokens.
-            truncate_first_sequence: if there is a specified max_length, this flag will choose which sequence
-                will be truncated.
+                from the main sequence returned. The value of this argument defines the number of additional tokens.
+            truncation_strategy: string selected in the following options:
+                - 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
+                    starting from the longest one at each token (when there is a pair of input sequences)
+                - 'only_first': Only truncate the first sequence
+                - 'only_second': Only truncate the second sequence
+                - 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
             return_tensors: (optional) can be set to 'tf' or 'pt' to return respectively TensorFlow tf.constant
                 or PyTorch torch.Tensor instead of a list of python integers.
             **kwargs: passed to the `self.tokenize()` method
@@ -787,12 +790,11 @@ class PreTrainedTokenizer(object):
                                       max_length=max_length,
                                       add_special_tokens=add_special_tokens,
                                       stride=stride,
-                                      truncate_first_sequence=truncate_first_sequence,
+                                      truncation_strategy=truncation_strategy,
                                       return_tensors=return_tensors)
 
-
     def prepare_for_model(self, ids, pair_ids=None, max_length=None, add_special_tokens=False, stride=0,
-                          truncate_first_sequence=True, return_tensors=None):
+                          truncation_strategy='longest_first', return_tensors=None):
         """
         Prepares a sequence of input id, or a pair of sequences of inputs ids so that it can be used by the model.
         It adds special tokens, truncates
@@ -809,41 +811,50 @@ class PreTrainedTokenizer(object):
                 to their model.
             stride: window stride for overflowing tokens. Can be useful for edge effect removal when using sequential
                 list of inputs.
-            truncate_first_sequence: if set to `True` and an optional second list of input ids is provided,
-                alongside a specified `max_length`, will truncate the first sequence if the total size is superior
-                than the specified `max_length`. If set to `False`, will truncate the second sequence instead.
+            truncation_strategy: string selected in the following options:
+                - 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
+                    starting from the longest one at each token (when there is a pair of input sequences)
+                - 'only_first': Only truncate the first sequence
+                - 'only_second': Only truncate the second sequence
+                - 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
             return_tensors: (optional) can be set to 'tf' or 'pt' to return respectively TensorFlow tf.constant
                 or PyTorch torch.Tensor instead of a list of python integers.
 
         Return:
-            a dictionary containing the `input_ids` as well as the `overflowing_tokens` if a `max_length` was given.
+            A Dictionary of shape::
+
+                {
+                    input_ids: list[int],
+                    overflowing_tokens: list[int] if a ``max_length`` is specified, else None
+                    special_tokens_mask: list[int] if ``add_special_tokens`` if set to ``True``
+                }
+
+            With the fields:
+                ``input_ids``: list of tokens to be fed to a model
+
+                ``overflowing_tokens``: list of overflowing tokens if a max length is specified.
+
+                ``special_tokens_mask``: if adding special tokens, this is a list of [0, 1], with 0 specifying special added
+                tokens and 1 specifying sequence tokens.
         """
         pair = bool(pair_ids is not None)
         len_ids = len(ids)
         len_pair_ids = len(pair_ids) if pair else 0
 
         encoded_inputs = {}
-        if max_length:
-            n_added_tokens = self.num_added_tokens(pair=pair) if add_special_tokens else 0
-            if pair and n_added_tokens + (len_pair_ids if truncate_first_sequence else len_ids) >= max_length:
-                logger.warning(
-                    "You supplied a pair of sequence in which the sequence that will not be truncated is longer than the maximum specified length."
-                    "This pair of sequences will not be truncated.")
-            else:
-                if n_added_tokens + len_ids + len_pair_ids > max_length:
-                    if truncate_first_sequence or not pair:
-                        encoded_inputs["overflowing_tokens"] = ids[max_length - len_pair_ids - n_added_tokens - stride:]
-                        ids = ids[:max_length - len_pair_ids - n_added_tokens]
-                    elif not truncate_first_sequence and pair:
-                        encoded_inputs["overflowing_tokens"] = pair_ids[max_length - len_ids - n_added_tokens - stride:]
-                        pair_ids = pair_ids[:max_length - len_ids - n_added_tokens]
-                    else:
-                        logger.warning(
-                            "Cannot truncate second sequence as it is not provided. No truncation.")
+        total_len = len_ids + len_pair_ids + (self.num_added_tokens(pair=pair) if add_special_tokens else 0)
+        if max_length and total_len > max_length:
+            ids, pair_ids, overflowing_tokens = self.truncate_sequences(ids, pair_ids=pair_ids,
+                                                                        num_tokens_to_remove=total_len-max_length,
+                                                                        truncation_strategy=truncation_strategy,
+                                                                        stride=stride)
+            encoded_inputs["overflowing_tokens"] = overflowing_tokens
+            encoded_inputs["num_truncated_tokens"] = total_len - max_length
 
         if add_special_tokens:
-            sequence = self.add_special_tokens_sequence_pair(ids, pair_ids) if pair else self.add_special_tokens_single_sequence(ids)
-            token_type_ids = self.create_token_type_ids_from_sequences(ids, pair_ids) if pair else [0] * len(sequence)
+            sequence = self.build_inputs_with_special_tokens(ids, pair_ids)
+            token_type_ids = self.create_token_type_ids_from_sequences(ids, pair_ids)
+            encoded_inputs["special_tokens_mask"] = self.get_special_tokens_mask(ids, pair_ids)
         else:
             sequence = ids + pair_ids if pair else ids
             token_type_ids = [0] * len(ids) + ([1] * len(pair_ids) if pair else [])
@@ -860,20 +871,89 @@ class PreTrainedTokenizer(object):
         encoded_inputs["input_ids"] = sequence
         encoded_inputs["token_type_ids"] = token_type_ids
 
+        if max_length and len(encoded_inputs["input_ids"]) > max_length:
+            encoded_inputs["input_ids"] = encoded_inputs["input_ids"][:max_length]
+            encoded_inputs["token_type_ids"] = encoded_inputs["token_type_ids"][:max_length]
+            encoded_inputs["special_tokens_mask"] = encoded_inputs["special_tokens_mask"][:max_length]
+
         return encoded_inputs
 
-    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
+    def truncate_sequences(self, ids, pair_ids=None, num_tokens_to_remove=0, truncation_strategy='longest_first', stride=0):
+        """Truncates a sequence pair in place to the maximum length.
+            truncation_strategy: string selected in the following options:
+                - 'longest_first' (default) Iteratively reduce the inputs sequence until the input is under max_length
+                    starting from the longest one at each token (when there is a pair of input sequences).
+                    Overflowing tokens only contains overflow from the first sequence.
+                - 'only_first': Only truncate the first sequence. raise an error if the first sequence is shorter or equal to than num_tokens_to_remove.
+                - 'only_second': Only truncate the second sequence
+                - 'do_not_truncate': Does not truncate (raise an error if the input sequence is longer than max_length)
+        """
+        if num_tokens_to_remove <= 0:
+            return ids, pair_ids, []
+
+        if truncation_strategy == 'longest_first':
+            overflowing_tokens = []
+            for _ in range(num_tokens_to_remove):
+                if pair_ids is None or len(ids) > len(pair_ids):
+                    overflowing_tokens = [ids[-1]] + overflowing_tokens
+                    ids = ids[:-1]
+                else:
+                    pair_ids = pair_ids[:-1]
+            window_len = min(len(ids), stride)
+            if window_len > 0:
+                overflowing_tokens = ids[-window_len:] + overflowing_tokens
+        elif truncation_strategy == 'only_first':
+            assert len(ids) > num_tokens_to_remove
+            window_len = min(len(ids), stride + num_tokens_to_remove)
+            overflowing_tokens = ids[-window_len:]
+            ids = ids[:-num_tokens_to_remove]
+        elif truncation_strategy == 'only_second':
+            assert pair_ids is not None and len(pair_ids) > num_tokens_to_remove
+            window_len = min(len(pair_ids), stride + num_tokens_to_remove)
+            overflowing_tokens = pair_ids[-window_len:]
+            pair_ids = pair_ids[:-num_tokens_to_remove]
+        elif truncation_strategy == 'do_not_truncate':
+            raise ValueError("Input sequence are too long for max_length. Please select a truncation strategy.")
+        else:
+            raise ValueError("Truncation_strategy should be selected in ['longest_first', 'only_first', 'only_second', 'do_not_truncate']")
+        return (ids, pair_ids, overflowing_tokens)
+
+    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
         logger.warning("This tokenizer does not make use of special tokens.")
+        if token_ids_1 is None:
+            return len(token_ids_0) * [0]
         return [0] * len(token_ids_0) + [1] * len(token_ids_1)
 
-    def add_special_tokens_single_sequence(self, token_ids):
-        logger.warning("This tokenizer does not make use of special tokens. The sequence has been returned with no modification.")
-        return token_ids
-
-    def add_special_tokens_sequence_pair(self, token_ids_0, token_ids_1):
-        logger.warning("This tokenizer does not make use of special tokens. The two sequences have been concatenated.")
+    def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
+        """
+        Build model inputs from a sequence or a pair of sequence for sequence classification tasks
+        by concatenating and adding special tokens.
+        A RoBERTa sequence has the following format:
+            single sequence: <s> X </s>
+            pair of sequences: <s> A </s></s> B </s>
+        """
+        logger.warning("This tokenizer does not make use of special tokens. Input is returned with no modification.")
+        if token_ids_1 is None:
+            return token_ids_0
         return token_ids_0 + token_ids_1
 
+    def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+                for sequence pairs
+            already_has_special_tokens: (default False) Set to True if the token list is already formated with
+                special tokens for the model
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+        return [0] * ((len(token_ids_1) if token_ids_1 else 0) + len(token_ids_0))
+
     def convert_ids_to_tokens(self, ids, skip_special_tokens=False):
         """ Converts a single index or a sequence of indices (integers) in a token "
             (resp.) a sequence of tokens (str/unicode), using the vocabulary and added tokens.
@@ -911,6 +991,11 @@ class PreTrainedTokenizer(object):
         Converts a sequence of ids (integer) in a string, using the tokenizer and vocabulary
         with options to remove special tokens and clean up tokenization spaces.
         Similar to doing ``self.convert_tokens_to_string(self.convert_ids_to_tokens(token_ids))``.
+
+        Args:
+            token_ids: list of tokenized input ids. Can be obtained using the `encode` or `encode_plus` methods.
+            skip_special_tokens: if set to True, will replace special tokens.
+            clean_up_tokenization_spaces: if set to True, will clean up the tokenization spaces.
         """
         filtered_tokens = self.convert_ids_to_tokens(token_ids, skip_special_tokens=skip_special_tokens)
 
@@ -933,20 +1018,11 @@ class PreTrainedTokenizer(object):
             sub_texts.append(self.convert_tokens_to_string(current_sub_text))
         text = ''.join(sub_texts)
 
-        if self._sep_token is not None and self._sep_token in text:
-            text = text.replace(self._cls_token, self._sep_token)
-            split_text = list(filter(lambda sentence: len(sentence) > 0, text.split(self._sep_token)))
-            if clean_up_tokenization_spaces:
-                clean_text = [self.clean_up_tokenization(text) for text in split_text]
-                return clean_text
-            else:
-                return split_text
+        if clean_up_tokenization_spaces:
+            clean_text = self.clean_up_tokenization(text)
+            return clean_text
         else:
-            if clean_up_tokenization_spaces:
-                clean_text = self.clean_up_tokenization(text)
-                return clean_text
-            else:
-                return text
+            return text
 
     @property
     def special_tokens_map(self):

transformers/tokenization_xlm.py

@@ -754,32 +754,59 @@ class XLMTokenizer(PreTrainedTokenizer):
         out_string = ''.join(tokens).replace('</w>', ' ').strip()
         return out_string
 
-    def add_special_tokens_single_sequence(self, token_ids):
+    def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
         """
-        Adds special tokens to a sequence for sequence classification tasks.
-        An XLM sequence has the following format: [CLS] X [SEP]
-        """
-        return [self.cls_token_id] + token_ids + [self.sep_token_id]
-
-    def add_special_tokens_sequence_pair(self, token_ids_0, token_ids_1):
-        """
-        Adds special tokens to a sequence pair for sequence classification tasks.
-        An XLM sequence pair has the following format: [CLS] A [SEP] B [SEP]
+        Build model inputs from a sequence or a pair of sequence for sequence classification tasks
+        by concatenating and adding special tokens.
+        A RoBERTa sequence has the following format:
+            single sequence: <s> X </s>
+            pair of sequences: <s> A </s></s> B </s>
         """
+        if token_ids_1 is None:
+            return [self.cls_token_id] + token_ids_0 + [self.sep_token_id]
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
         return cls + token_ids_0 + sep + token_ids_1 + sep
 
-    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
+    def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+                for sequence pairs
+            already_has_special_tokens: (default False) Set to True if the token list is already formated with
+                special tokens for the model
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+
+        if already_has_special_tokens:
+            if token_ids_1 is not None:
+                raise ValueError("You should not supply a second sequence if the provided sequence of "
+                                 "ids is already formated with special tokens for the model.")
+            return list(map(lambda x: 1 if x in [self.sep_token_id, self.cls_token_id] else 0, token_ids_0))
+
+        if token_ids_1 is not None:
+            return [1] + ([0] * len(token_ids_0)) + [1] + ([0] * len(token_ids_1)) + [1]
+        return [1] + ([0] * len(token_ids_0)) + [1]
+
+    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
         """
         Creates a mask from the two sequences passed to be used in a sequence-pair classification task.
         An XLM sequence pair mask has the following format:
         0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1
         | first sequence    | second sequence
+
+        if token_ids_1 is None, only returns the first portion of the mask (0's).
         """
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
-
+        if token_ids_1 is None:
+            return len(cls + token_ids_0 + sep) * [0]
         return len(cls + token_ids_0 + sep) * [0] + len(token_ids_1 + sep) * [1]
 
     def save_vocabulary(self, save_directory):

transformers/tokenization_xlnet.py

@@ -181,36 +181,61 @@ class XLNetTokenizer(PreTrainedTokenizer):
         out_string = ''.join(tokens).replace(SPIECE_UNDERLINE, ' ').strip()
         return out_string
 
-    def add_special_tokens_single_sequence(self, token_ids):
+    def build_inputs_with_special_tokens(self, token_ids_0, token_ids_1=None):
         """
-        Adds special tokens to a sequence for sequence classification tasks.
-        An XLNet sequence has the following format: X [SEP][CLS]
+        Build model inputs from a sequence or a pair of sequence for sequence classification tasks
+        by concatenating and adding special tokens.
+        A RoBERTa sequence has the following format:
+            single sequence: <s> X </s>
+            pair of sequences: <s> A </s></s> B </s>
         """
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
-        return token_ids + sep + cls
-
-    def add_special_tokens_sequence_pair(self, token_ids_0, token_ids_1):
-        """
-        Adds special tokens to a sequence pair for sequence classification tasks.
-        An XLNet sequence pair has the following format: A [SEP] B [SEP][CLS]
-        """
-
-        sep = [self.sep_token_id]
-        cls = [self.cls_token_id]
+        if token_ids_1 is None:
+            return token_ids_0 + sep + cls
         return token_ids_0 + sep + token_ids_1 + sep + cls
 
-    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1):
+    def get_special_tokens_mask(self, token_ids_0, token_ids_1=None, already_has_special_tokens=False):
+        """
+        Retrieves sequence ids from a token list that has no special tokens added. This method is called when adding
+        special tokens using the tokenizer ``prepare_for_model`` or ``encode_plus`` methods.
+
+        Args:
+            token_ids_0: list of ids (must not contain special tokens)
+            token_ids_1: Optional list of ids (must not contain special tokens), necessary when fetching sequence ids
+                for sequence pairs
+            already_has_special_tokens: (default False) Set to True if the token list is already formated with
+                special tokens for the model
+
+        Returns:
+            A list of integers in the range [0, 1]: 0 for a special token, 1 for a sequence token.
+        """
+
+        if already_has_special_tokens:
+            if token_ids_1 is not None:
+                raise ValueError("You should not supply a second sequence if the provided sequence of "
+                                 "ids is already formated with special tokens for the model.")
+            return list(map(lambda x: 1 if x in [self.sep_token_id, self.cls_token_id] else 0, token_ids_0))
+
+        if token_ids_1 is not None:
+            return ([0] * len(token_ids_0)) + [1] + ([0] * len(token_ids_1)) + [1, 1]
+        return ([0] * len(token_ids_0)) + [1, 1]
+
+    def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None):
         """
         Creates a mask from the two sequences passed to be used in a sequence-pair classification task.
         A BERT sequence pair mask has the following format:
         0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 2
         | first sequence    | second sequence     | CLS segment ID
+        
+        if token_ids_1 is None, only returns the first portion of the mask (0's).
         """
         sep = [self.sep_token_id]
         cls = [self.cls_token_id]
         cls_segment_id = [2]
 
+        if token_ids_1 is None:
+            return len(token_ids_0 + sep + cls) * [0]
         return len(token_ids_0 + sep) * [0] + len(token_ids_1 + sep) * [1] + cls_segment_id
 
     def save_vocabulary(self, save_directory):