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Improvements to PretrainedConfig documentation (#5642)

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* Update PretrainedConfig doc

* Formatting

* Small fixes

* Forgotten args and more cleanup
This commit is contained in:
Sylvain Gugger
2020-07-10 10:31:47 -04:00
committed by GitHub
parent bfacb2e34f
commit b2747af543
2 changed files with 167 additions and 84 deletions
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4
docs/source/main_classes/configuration.rst
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@@ -1,7 +1,9 @@
Configuration
----------------------------------------------------
The base class ``PretrainedConfig`` implements the common methods for loading/saving a configuration either from a local file or directory, or from a pretrained model configuration provided by the library (downloaded from HuggingFace's AWS S3 repository).
The base class ``PretrainedConfig`` implements the common methods for loading/saving a configuration either from a
local file or directory, or from a pretrained model configuration provided by the library (downloaded from
HuggingFace's AWS S3 repository).
``PretrainedConfig``
~~~~~~~~~~~~~~~~~~~~~

247
src/transformers/configuration_utils.py
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@@ -20,7 +20,7 @@ import copy
import json
import logging
import os
from typing import Dict, Tuple
from typing import Any, Dict, Tuple
from .file_utils import CONFIG_NAME, cached_path, hf_bucket_url, is_remote_url
@@ -30,26 +30,102 @@ logger = logging.getLogger(__name__)
class PretrainedConfig(object):
r""" Base class for all configuration classes.
Handles a few parameters common to all models' configurations as well as methods for loading/downloading/saving configurations.
Handles a few parameters common to all models' configurations as well as methods for loading/downloading/saving
configurations.
Note:
A configuration file can be loaded and saved to disk. Loading the configuration file and using this file to initialize a model does **not** load the model weights.
A configuration file can be loaded and saved to disk. Loading the configuration file and using this file to
initialize a model does **not** load the model weights.
It only affects the model's configuration.
Class attributes (overridden by derived classes):
- ``model_type``: a string that identifies the model type, that we serialize into the JSON file, and that we use to recreate the correct object in :class:`~transformers.AutoConfig`.
Class attributes (overridden by derived classes)
- **model_type** (:obj:`str`): An identifier for the model type, serialized into the JSON file, and used to
recreate the correct object in :class:`~transformers.AutoConfig`.
Args:
finetuning_task (:obj:`string` or :obj:`None`, `optional`, defaults to :obj:`None`):
Name of the task used to fine-tune the model. This can be used when converting from an original (TensorFlow or PyTorch) checkpoint.
num_labels (:obj:`int`, `optional`, defaults to `2`):
Number of classes to use when the model is a classification model (sequences/tokens)
output_hidden_states (:obj:`bool`, `optional`, defaults to :obj:`False`):
Should the model returns all hidden-states.
Whether or not the model should return all hidden-states.
output_attentions (:obj:`bool`, `optional`, defaults to :obj:`False`):
Should the model returns all attentions.
torchscript (:obj:`bool`, `optional`, defaults to :obj:`False`):
Is the model used with Torchscript (for PyTorch models).
Whether or not the model should returns all attentions.
use_cache (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether or not the model should return the last key/values attentions (not used by all models).
is_encoder_decoder (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether the model is used as an encoder/decoder or not.
is_decoder (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether the model is used as decoder or not (in which case it's used as an encoder).
prune_heads (:obj:`Dict[int, List[int]]`, `optional`, defaults to :obj:`{}`):
Pruned heads of the model. The keys are the selected layer indices and the associated values, the list
of heads to prune in said layer.
For instance ``{1: [0, 2], 2: [2, 3]}`` will prune heads 0 and 2 on layer 1 and heads 2 and 3 on layer
2.
xla_device (:obj:`bool`, `optional`):
A flag to indicate if TPU are available or not.
Parameters for sequence generation
- **max_length** (:obj:`int`, `optional`, defaults to 20) -- Maximum length that will be used by
default in the :obj:`generate` method of the model.
- **min_length** (:obj:`int`, `optional`, defaults to 10) -- Minimum length that will be used by
default in the :obj:`generate` method of the model.
- **do_sample** (:obj:`bool`, `optional`, defaults to :obj:`False`) -- Flag that will be used by default in
the :obj:`generate` method of the model. Whether or not to use sampling ; use greedy decoding otherwise.
- **early_stopping** (:obj:`bool`, `optional`, defaults to :obj:`False`) -- Flag that will be used by
default in the :obj:`generate` method of the model. Whether to stop the beam search when at least
``num_beams`` sentences are finished per batch or not.
- **num_beams** (:obj:`int`, `optional`, defaults to 1) -- Number of beams for beam search that will be
used by default in the :obj:`generate` method of the model. 1 means no beam search.
- **temperature** (:obj:`float`, `optional`, defaults to 1) -- The value used to module the next token
probabilities that will be used by default in the :obj:`generate` method of the model. Must be strictly
positive.
- **top_k** (:obj:`int`, `optional`, defaults to 50) -- Number of highest probability vocabulary tokens to
keep for top-k-filtering that will be used by default in the :obj:`generate` method of the model.
- **top_p** (:obj:`float`, `optional`, defaults to 1) -- Value that will be used by default in the
:obj:`generate` method of the model for ``top_p``. If set to float < 1, only the most probable tokens
with probabilities that add up to ``top_p`` or highest are kept for generation.
- **repetition_penalty** (:obj:`float`, `optional`, defaults to 1) -- Parameter for repetition penalty
that will be used by default in the :obj:`generate` method of the model. 1.0 means no penalty.
- **length_penalty** (:obj:`float`, `optional`, defaults to 1) -- Exponential penalty to the length that
will be used by default in the :obj:`generate` method of the model.
- **no_repeat_ngram_size** (:obj:`int`, `optional`, defaults to 0) -- Value that will be used by default
in the :obj:`generate` method of the model for ``no_repeat_ngram_size``. If set to int > 0, all ngrams of
that size can only occur once.
- **bad_words_ids** (:obj:`List[int]`, `optional`) -- List of token ids that are not allowed to be
generated that will be used by default in the :obj:`generate` method of the model. In order to get the
tokens of the words that should not appear in the generated text, use
:obj:`tokenizer.encode(bad_word, add_prefix_space=True)`.
- **num_return_sequences** (:obj:`int`, `optional`, defaults to 1) -- Number of independently computed
returned sequences for each element in the batch that will be used by default in the :obj:`generate`
method of the model.
Parameters for fine-tuning tasks
- **architectures** (:obj:List[`str`], `optional`) -- Model architectures that can be used with the
model pretrained weights.
- **finetuning_task** (:obj:`str`, `optional`) -- Name of the task used to fine-tune the model. This can be
used when converting from an original (TensorFlow or PyTorch) checkpoint.
- **id2label** (:obj:`List[str]`, `optional`) -- A map from index (for instance prediction index, or target
index) to label.
- **label2id** (:obj:`Dict[str, int]`, `optional`) -- A map from label to index for the model.
- **num_labels** (:obj:`int`, `optional`) -- Number of labels to use in the last layer added to the model,
typically for a classification task.
- **task_specific_params** (:obj:`Dict[str, Any]`, `optional`) -- Additional keyword arguments to store for
the current task.
Parameters linked to the tokenizer
- **prefix** (:obj:`str`, `optional`) -- A specific prompt that should be added at the beginning of each
text before calling the model.
- **bos_token_id** (:obj:`int`, `optional`)) -- The id of the `beginning-of-stream` token.
- **pad_token_id** (:obj:`int`, `optional`)) -- The id of the `padding` token.
- **eos_token_id** (:obj:`int`, `optional`)) -- The id of the `end-of-stream` token.
- **decoder_start_token_id** (:obj:`int`, `optional`)) -- If an encoder-decoder model starts decoding with
a different token than `bos`, the id of that token.
PyTorch specific parameters
- **torchscript** (:obj:`bool`, `optional`, defaults to :obj:`False`) -- Whether or not the model should be
used with Torchscript.
TensorFlow specific parameters
- **use_bfloat16** (:obj:`bool`, `optional`, defaults to :obj:`False`) -- Whether or not the model should
use BFloat16 scalars (only used by some TensorFlow models).
"""
model_type: str = ""
@@ -115,22 +191,22 @@ class PretrainedConfig(object):
raise err
@property
def num_labels(self):
def num_labels(self) -> int:
return len(self.id2label)
@num_labels.setter
def num_labels(self, num_labels):
def num_labels(self, num_labels: int):
self.id2label = {i: "LABEL_{}".format(i) for i in range(num_labels)}
self.label2id = dict(zip(self.id2label.values(), self.id2label.keys()))
def save_pretrained(self, save_directory):
def save_pretrained(self, save_directory: str):
"""
Save a configuration object to the directory `save_directory`, so that it
can be re-loaded using the :func:`~transformers.PretrainedConfig.from_pretrained` class method.
Save a configuration object to the directory ``save_directory``, so that it can be re-loaded using the
:func:`~transformers.PretrainedConfig.from_pretrained` class method.
Args:
save_directory (:obj:`string`):
Directory where the configuration JSON file will be saved.
save_directory (:obj:`str`):
Directory where the configuration JSON file will be saved (will be created if it does not exist).
"""
if os.path.isfile(save_directory):
raise AssertionError("Provided path ({}) should be a directory, not a file".format(save_directory))
@@ -142,45 +218,49 @@ class PretrainedConfig(object):
logger.info("Configuration saved in {}".format(output_config_file))
@classmethod
def from_pretrained(cls, pretrained_model_name_or_path, **kwargs) -> "PretrainedConfig":
def from_pretrained(cls, pretrained_model_name_or_path: str, **kwargs) -> "PretrainedConfig":
r"""
Instantiate a :class:`~transformers.PretrainedConfig` (or a derived class) from a pre-trained model configuration.
Instantiate a :class:`~transformers.PretrainedConfig` (or a derived class) from a pretrained model
configuration.
Args:
pretrained_model_name_or_path (:obj:`string`):
either:
- a string with the `shortcut name` of a pre-trained model configuration to load from cache or
download, e.g.: ``bert-base-uncased``.
- a string with the `identifier name` of a pre-trained model configuration that was user-uploaded to
our S3, e.g.: ``dbmdz/bert-base-german-cased``.
- a path to a `directory` containing a configuration file saved using the
:func:`~transformers.PretrainedConfig.save_pretrained` method, e.g.: ``./my_model_directory/``.
- a path or url to a saved configuration JSON `file`, e.g.:
``./my_model_directory/configuration.json``.
cache_dir (:obj:`string`, `optional`):
Path to a directory in which a downloaded pre-trained model
configuration should be cached if the standard cache should not be used.
kwargs (:obj:`Dict[str, any]`, `optional`):
The values in kwargs of any keys which are configuration attributes will be used to override the loaded
values. Behavior concerning key/value pairs whose keys are *not* configuration attributes is
controlled by the `return_unused_kwargs` keyword parameter.
pretrained_model_name_or_path (:obj:`str`):
This can be either:
- the `shortcut name` of a pretrained model configuration to load from cache or download, e.g.,
``bert-base-uncased``.
- the `identifier name` of a pretrained model configuration that was uploaded to our S3 by any user,
e.g., ``dbmdz/bert-base-german-cased``.
- a path to a `directory` containing a configuration file saved using the
:func:`~transformers.PretrainedConfig.save_pretrained` method, e.g., ``./my_model_directory/``.
- a path or url to a saved configuration JSON `file`, e.g.,
``./my_model_directory/configuration.json``.
cache_dir (:obj:`str`, `optional`):
Path to a directory in which a downloaded pretrained model configuration should be cached if the
standard cache should not be used.
force_download (:obj:`bool`, `optional`, defaults to :obj:`False`):
Force to (re-)download the model weights and configuration files and override the cached versions if they exist.
Wheter or not to force to (re-)download the configuration files and override the cached versions if they
exist.
resume_download (:obj:`bool`, `optional`, defaults to :obj:`False`):
Do not delete incompletely recieved file. Attempt to resume the download if such a file exists.
proxies (:obj:`Dict`, `optional`):
A dictionary of proxy servers to use by protocol or endpoint, e.g.:
Whether or not to delete incompletely received file. Attempts to resume the download if such a file
exists.
proxies (:obj:`Dict[str, str]`, `optional`):
A dictionary of proxy servers to use by protocol or endpoint, e.g.,
:obj:`{'http': 'foo.bar:3128', 'http://hostname': 'foo.bar:4012'}.`
The proxies are used on each request.
return_unused_kwargs: (`optional`) bool:
If False, then this function returns just the final configuration object.
If True, then this functions returns a :obj:`Tuple(config, unused_kwargs)` where `unused_kwargs` is a
dictionary consisting of the key/value pairs whose keys are not configuration attributes: ie the part
of kwargs which has not been used to update `config` and is otherwise ignored.
return_unused_kwargs (:obj:`bool`, `optional`, defaults to :obj:`False`):
If :obj:`False`, then this function returns just the final configuration object.
If :obj:`True`, then this functions returns a :obj:`Tuple(config, unused_kwargs)` where `unused_kwargs`
is a dictionary consisting of the key/value pairs whose keys are not configuration attributes: i.e.,
the part of ``kwargs`` which has not been used to update ``config`` and is otherwise ignored.
kwargs (:obj:`Dict[str, Any]`, `optional`):
The values in kwargs of any keys which are configuration attributes will be used to override the loaded
values. Behavior concerning key/value pairs whose keys are *not* configuration attributes is
controlled by the ``return_unused_kwargs`` keyword parameter.
Returns:
:class:`PretrainedConfig`: An instance of a configuration object
:class:`PretrainedConfig`: The configuration object instantiated from this pretrained model.
Examples::
@@ -201,17 +281,17 @@ class PretrainedConfig(object):
return cls.from_dict(config_dict, **kwargs)
@classmethod
def get_config_dict(cls, pretrained_model_name_or_path: str, **kwargs) -> Tuple[Dict, Dict]:
def get_config_dict(cls, pretrained_model_name_or_path: str, **kwargs) -> Tuple[Dict[str, Any], Dict[str, Any]]:
"""
From a `pretrained_model_name_or_path`, resolve to a dictionary of parameters, to be used
for instantiating a Config using `from_dict`.
From a ``pretrained_model_name_or_path``, resolve to a dictionary of parameters, to be used
for instantiating a :class:`~transformers.PretrainedConfig` using ``from_dict``.
Parameters:
pretrained_model_name_or_path (:obj:`string`):
pretrained_model_name_or_path (:obj:`str`):
The identifier of the pre-trained checkpoint from which we want the dictionary of parameters.
Returns:
:obj:`Tuple[Dict, Dict]`: The dictionary that will be used to instantiate the configuration object.
:obj:`Tuple[Dict, Dict]`: The dictionary(ies) that will be used to instantiate the configuration object.
"""
cache_dir = kwargs.pop("cache_dir", None)
@@ -266,20 +346,20 @@ class PretrainedConfig(object):
return config_dict, kwargs
@classmethod
def from_dict(cls, config_dict: Dict, **kwargs) -> "PretrainedConfig":
def from_dict(cls, config_dict: Dict[str, Any], **kwargs) -> "PretrainedConfig":
"""
Constructs a `Config` from a Python dictionary of parameters.
Instantiates a :class:`~transformers.PretrainedConfig` from a Python dictionary of parameters.
Args:
config_dict (:obj:`Dict[str, any]`):
Dictionary that will be used to instantiate the configuration object. Such a dictionary can be retrieved
from a pre-trained checkpoint by leveraging the :func:`~transformers.PretrainedConfig.get_config_dict`
method.
kwargs (:obj:`Dict[str, any]`):
config_dict (:obj:`Dict[str, Any]`):
Dictionary that will be used to instantiate the configuration object. Such a dictionary can be
retrieved from a pretrained checkpoint by leveraging the
:func:`~transformers.PretrainedConfig.get_config_dict` method.
kwargs (:obj:`Dict[str, Any]`):
Additional parameters from which to initialize the configuration object.
Returns:
:class:`PretrainedConfig`: An instance of a configuration object
:class:`PretrainedConfig`: The configuration object instantiated from those parameters.
"""
return_unused_kwargs = kwargs.pop("return_unused_kwargs", False)
@@ -306,14 +386,14 @@ class PretrainedConfig(object):
@classmethod
def from_json_file(cls, json_file: str) -> "PretrainedConfig":
"""
Constructs a `Config` from the path to a json file of parameters.
Instantiates a :class:`~transformers.PretrainedConfig` from the path to a JSON file of parameters.
Args:
json_file (:obj:`string`):
json_file (:obj:`str`):
Path to the JSON file containing the parameters.
Returns:
:class:`PretrainedConfig`: An instance of a configuration object
:class:`PretrainedConfig`: The configuration object instantiated from that JSON file.
"""
config_dict = cls._dict_from_json_file(json_file)
@@ -331,14 +411,14 @@ class PretrainedConfig(object):
def __repr__(self):
return "{} {}".format(self.__class__.__name__, self.to_json_string())
def to_diff_dict(self):
def to_diff_dict(self) -> Dict[str, Any]:
"""
Removes all attributes from config which correspond to the default
config attributes for better readability and serializes to a Python
dictionary.
Returns:
:obj:`Dict[str, any]`: Dictionary of all the attributes that make up this configuration instance,
:obj:`Dict[str, Any]`: Dictionary of all the attributes that make up this configuration instance,
"""
config_dict = self.to_dict()
@@ -354,28 +434,29 @@ class PretrainedConfig(object):
return serializable_config_dict
def to_dict(self):
def to_dict(self) -> Dict[str, Any]:
"""
Serializes this instance to a Python dictionary.
Returns:
:obj:`Dict[str, any]`: Dictionary of all the attributes that make up this configuration instance,
:obj:`Dict[str, Any]`: Dictionary of all the attributes that make up this configuration instance.
"""
output = copy.deepcopy(self.__dict__)
if hasattr(self.__class__, "model_type"):
output["model_type"] = self.__class__.model_type
return output
def to_json_string(self, use_diff=True):
def to_json_string(self, use_diff: bool = True) -> str:
"""
Serializes this instance to a JSON string.
Args:
use_diff (:obj:`bool`):
If set to True, only the difference between the config instance and the default PretrainedConfig() is serialized to JSON string.
use_diff (:obj:`bool`, `optional`, defaults to :obj:`True`):
If set to ``True``, only the difference between the config instance and the default
``PretrainedConfig()`` is serialized to JSON string.
Returns:
:obj:`string`: String containing all the attributes that make up this configuration instance in JSON format.
:obj:`str`: String containing all the attributes that make up this configuration instance in JSON format.
"""
if use_diff is True:
config_dict = self.to_diff_dict()
@@ -383,26 +464,26 @@ class PretrainedConfig(object):
config_dict = self.to_dict()
return json.dumps(config_dict, indent=2, sort_keys=True) + "\n"
def to_json_file(self, json_file_path, use_diff=True):
def to_json_file(self, json_file_path: str, use_diff: bool = True):
"""
Save this instance to a json file.
Save this instance to a JSON file.
Args:
json_file_path (:obj:`string`):
json_file_path (:obj:`str`):
Path to the JSON file in which this configuration instance's parameters will be saved.
use_diff (:obj:`bool`):
If set to True, only the difference between the config instance and the default PretrainedConfig() is serialized to JSON file.
use_diff (:obj:`bool`, `optional`, defaults to :obj:`True`):
If set to ``True``, only the difference between the config instance and the default
``PretrainedConfig()`` is serialized to JSON file.
"""
with open(json_file_path, "w", encoding="utf-8") as writer:
writer.write(self.to_json_string(use_diff=use_diff))
def update(self, config_dict: Dict):
def update(self, config_dict: Dict[str, Any]):
"""
Updates attributes of this class
with attributes from `config_dict`.
Updates attributes of this class with attributes from ``config_dict``.
Args:
:obj:`Dict[str, any]`: Dictionary of attributes that shall be updated for this class.
config_dict (:obj:`Dict[str, Any]`): Dictionary of attributes that shall be updated for this class.
"""
for key, value in config_dict.items():
setattr(self, key, value)