Cleanup documentation for BART, Marian, MBART and Pegasus (#7523)

* Cleanup documentation for BART, Marian, MBART and Pegasus

* Cleanup documentation for BART, Marian, MBART and Pegasus
This commit is contained in:
Sylvain Gugger
2020-10-05 04:22:12 -04:00
committed by GitHub
parent 5e941bece2
commit e2c935f561
16 changed files with 594 additions and 284 deletions

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@@ -1,36 +1,51 @@
MarianMT
-----------------------------------------------------------------------------------------------------------------------
**Bugs:** If you see something strange,
file a `Github Issue <https://github.com/huggingface/transformers/issues/new?assignees=sshleifer&labels=&template=bug-report.md&title>`__ and assign
@sshleifer. Translations should be similar, but not identical to, output in the test set linked to in each model card.
**Bugs:** If you see something strange, file a `Github Issue
<https://github.com/huggingface/transformers/issues/new?assignees=sshleifer&labels=&template=bug-report.md&title>`__
and assign @sshleifer.
Translations should be similar, but not identical to, output in the test set linked to in each model card.
Implementation Notes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- Each model is about 298 MB on disk, there are 1,000+ models.
- Each model is about 298 MB on disk, there are more than 1,000 models.
- The list of supported language pairs can be found `here <https://huggingface.co/Helsinki-NLP>`__.
- models were originally trained by `Jörg Tiedemann <https://researchportal.helsinki.fi/en/persons/j%C3%B6rg-tiedemann>`__ using the `Marian <https://marian-nmt.github.io/>`_ C++ library, which supports fast training and translation.
- All models are transformer encoder-decoders with 6 layers in each component. Each model's performance is documented in a model card.
- Models were originally trained by
`Jörg Tiedemann <https://researchportal.helsinki.fi/en/persons/j%C3%B6rg-tiedemann>`__ using the
`Marian <https://marian-nmt.github.io/>`__ C++ library, which supports fast training and translation.
- All models are transformer encoder-decoders with 6 layers in each component. Each model's performance is documented
in a model card.
- The 80 opus models that require BPE preprocessing are not supported.
- The modeling code is the same as ``BartForConditionalGeneration`` with a few minor modifications:
- static (sinusoid) positional embeddings (``MarianConfig.static_position_embeddings=True``)
- a new final_logits_bias (``MarianConfig.add_bias_logits=True``)
- no layernorm_embedding (``MarianConfig.normalize_embedding=False``)
- the model starts generating with pad_token_id (which has 0 token_embedding) as the prefix. (Bart uses <s/>)
- Code to bulk convert models can be found in ``convert_marian_to_pytorch.py``
- The modeling code is the same as :class:`~transformers.BartForConditionalGeneration` with a few minor modifications:
- static (sinusoid) positional embeddings (:obj:`MarianConfig.static_position_embeddings=True`)
- a new final_logits_bias (:obj:`MarianConfig.add_bias_logits=True`)
- no layernorm_embedding (:obj:`MarianConfig.normalize_embedding=False`)
- the model starts generating with :obj:`pad_token_id` (which has 0 as a token_embedding) as the prefix (Bart uses
:obj:`<s/>`),
- Code to bulk convert models can be found in ``convert_marian_to_pytorch.py``.
Naming
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- All model names use the following format: ``Helsinki-NLP/opus-mt-{src}-{tgt}``
- The language codes used to name models are inconsistent. Two digit codes can usually be found `here <https://developers.google.com/admin-sdk/directory/v1/languages>`_, three digit codes require googling "language code {code}".
- Codes formatted like ``es_AR`` are usually ``code_{region}``. That one is spanish documents from Argentina.
- All model names use the following format: :obj:`Helsinki-NLP/opus-mt-{src}-{tgt}`
- The language codes used to name models are inconsistent. Two digit codes can usually be found `here
<https://developers.google.com/admin-sdk/directory/v1/languages>`__, three digit codes require googling
"language code {code}".
- Codes formatted like :obj:`es_AR` are usually :obj:`code_{region}`. That one is Spanish from Argentina.
Multilingual Models
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
All model names use the following format: ``Helsinki-NLP/opus-mt-{src}-{tgt}``:
- if ``src`` is in all caps, the model supports multiple input languages, you can figure out which ones by looking at the model card, or the Group Members `mapping <https://gist.github.com/sshleifer/6d20e7761931b08e73c3219027b97b8a>`_ .
- if ``tgt`` is in all caps, the model can output multiple languages, and you should specify a language code by prepending the desired output language to the src_text
All model names use the following format: :obj:`Helsinki-NLP/opus-mt-{src}-{tgt}`:
- If :obj:`src` is in all caps, the model supports multiple input languages, you can figure out which ones by
looking at the model card, or the Group Members `mapping
<https://gist.github.com/sshleifer/6d20e7761931b08e73c3219027b97b8a>`_ .
- If :obj:`tgt` is in all caps, the model can output multiple languages, and you should specify a language code by
prepending the desired output language to the :obj:`src_text`.
- You can see a tokenizer's supported language codes in ``tokenizer.supported_language_codes``
Example of translating english to many romance languages, using language codes:
@@ -54,12 +69,20 @@ Example of translating english to many romance languages, using language codes:
# 'Isto deve ir para o português.',
# 'Y esto al español']
Sometimes, models were trained on collections of languages that do not resolve to a group. In this case, _ is used as a separator for src or tgt, as in ``'Helsinki-NLP/opus-mt-en_el_es_fi-en_el_es_fi'``. These still require language codes.
There are many supported regional language codes, like ``>>es_ES<<`` (Spain) and ``>>es_AR<<`` (Argentina), that do not seem to change translations. I have not found these to provide different results than just using ``>>es<<``.
Sometimes, models were trained on collections of languages that do not resolve to a group. In this case, _ is used as a
separator for src or tgt, as in :obj:`Helsinki-NLP/opus-mt-en_el_es_fi-en_el_es_fi`. These still require language
codes.
For Example:
- ``Helsinki-NLP/opus-mt-NORTH_EU-NORTH_EU``: translates from all NORTH_EU languages (see `mapping <https://gist.github.com/sshleifer/6d20e7761931b08e73c3219027b97b8a>`_) to all NORTH_EU languages. Use a special language code like ``>>de<<`` to specify output language.
- ``Helsinki-NLP/opus-mt-ROMANCE-en``: translates from many romance languages to english, no codes needed since there is only 1 tgt language.
There are many supported regional language codes, like :obj:`>>es_ES<<` (Spain) and :obj:`>>es_AR<<` (Argentina), that
do not seem to change translations. I have not found these to provide different results than just using :obj:`>>es<<`.
For example:
- `Helsinki-NLP/opus-mt-NORTH_EU-NORTH_EU`: translates from all NORTH_EU languages (see `mapping
<https://gist.github.com/sshleifer/6d20e7761931b08e73c3219027b97b8a>`_) to all NORTH_EU languages. Use a special
language code like :obj:`>>de<<` to specify output language.
- `Helsinki-NLP/opus-mt-ROMANCE-en`: translates from many romance languages to english, no codes needed since there
is only one target language.
@@ -86,13 +109,6 @@ Code to see available pretrained models:
suffix = [x.split('/')[1] for x in model_ids]
multi_models = [f'{org}/{s}' for s in suffix if s != s.lower()]
MarianMTModel
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Pytorch version of marian-nmt's transformer.h (c++). Designed for the OPUS-NMT translation checkpoints.
Model API is identical to BartForConditionalGeneration.
Available models are listed at `Model List <https://huggingface.co/models?search=Helsinki-NLP>`__
This class inherits nearly all functionality from ``BartForConditionalGeneration``, see that page for method signatures.
MarianConfig
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -107,5 +123,7 @@ MarianTokenizer
:members: prepare_seq2seq_batch
MarianMTModel
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.. autoclass:: transformers.MarianMTModel