# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2018 The Google AI Language Team Authors 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.
import random
import warnings
from collections.abc import Mapping
from dataclasses import dataclass
from typing import Any, Callable, Dict, List, NewType, Optional, Tuple, Union
import numpy as np
import paddle
from ..transformers import BertTokenizer
from ..transformers.tokenizer_utils_base import (
BatchEncoding,
PaddingStrategy,
PretrainedTokenizerBase,
)
__all__ = [
"DataCollatorWithPadding",
"default_data_collator",
"DataCollator",
"DefaultDataCollator",
"DataCollatorForTokenClassification",
"DataCollatorForSeq2Seq",
"DataCollatorForLanguageModeling",
"DataCollatorForWholeWordMask",
]
InputDataClass = NewType("InputDataClass", Any)
"""
A DataCollator is a function that takes a list of samples from a Dataset and collate them into a batch, as a dictionary
of PaddlePaddle tensors or NumPy arrays.
"""
DataCollator = NewType("DataCollator", Callable[[List[InputDataClass]], Dict[str, Any]])
class DataCollatorMixin:
def __call__(self, features, return_tensors=None):
if return_tensors is None:
return_tensors = self.return_tensors
if return_tensors == "pd":
return self.paddle_call(features)
elif return_tensors == "np":
return self.numpy_call(features)
else:
raise ValueError(f"Framework '{return_tensors}' not recognized!")
[文档]def default_data_collator(features: List[InputDataClass], return_tensors="pd") -> Dict[str, Any]:
"""
Very simple data collator that simply collates batches of dict-like objects and performs special handling for
potential keys named:
- `label`: handles a single value (int or float) per object
- `label_ids`: handles a list of values per object
Does not do any additional preprocessing: property names of the input object will be used as corresponding inputs
to the model. See glue and ner for example of how it's useful.
"""
# In this function we'll make the assumption that all `features` in the batch
# have the same attributes.
# So we will look at the first element as a proxy for what attributes exist
# on the whole batch.
if return_tensors == "pd":
return paddle_default_data_collator(features)
elif return_tensors == "np":
return numpy_default_data_collator(features)
def paddle_default_data_collator(features: List[InputDataClass]) -> Dict[str, Any]:
if not isinstance(features[0], (dict, BatchEncoding)):
features = [vars(f) for f in features]
first = features[0]
batch = {}
# Special handling for labels.
# Ensure that tensor is created with the correct type
# (it should be automatically the case, but let's make sure of it.)
if "label" in first and first["label"] is not None:
label = first["label"].item() if isinstance(first["label"], paddle.Tensor) else first["label"]
dtype = "int64" if isinstance(label, int) else "float32"
batch["labels"] = paddle.to_tensor([f["label"] for f in features], dtype=dtype)
elif "label_ids" in first and first["label_ids"] is not None:
if isinstance(first["label_ids"], paddle.Tensor):
batch["labels"] = paddle.stack([f["label_ids"] for f in features])
else:
dtype = "int64" if type(first["label_ids"][0]) is int else "float32"
batch["labels"] = paddle.to_tensor([f["label_ids"] for f in features], dtype=dtype)
# Handling of all other possible keys.
# Again, we will use the first element to figure out which key/values are not None for this model.
for k, v in first.items():
if k not in ("label", "label_ids") and v is not None and not isinstance(v, str):
if isinstance(v, paddle.Tensor):
batch[k] = paddle.stack([f[k] for f in features])
else:
batch[k] = paddle.to_tensor([f[k] for f in features])
return batch
def numpy_default_data_collator(features: List[InputDataClass]) -> Dict[str, Any]:
if not isinstance(features[0], (dict, BatchEncoding)):
features = [vars(f) for f in features]
first = features[0]
batch = {}
# Special handling for labels.
# Ensure that tensor is created with the correct type
# (it should be automatically the case, but let's make sure of it.)
if "label" in first and first["label"] is not None:
label = first["label"].item() if isinstance(first["label"], np.ndarray) else first["label"]
dtype = np.int64 if isinstance(label, int) else np.float32
batch["labels"] = np.array([f["label"] for f in features], dtype=dtype)
elif "label_ids" in first and first["label_ids"] is not None:
if isinstance(first["label_ids"], np.ndarray):
batch["labels"] = np.stack([f["label_ids"] for f in features])
else:
dtype = np.int64 if type(first["label_ids"][0]) is int else np.float32
batch["labels"] = np.array([f["label_ids"] for f in features], dtype=dtype)
# Handling of all other possible keys.
# Again, we will use the first element to figure out which key/values are not None for this model.
for k, v in first.items():
if k not in ("label", "label_ids") and v is not None and not isinstance(v, str):
if isinstance(v, np.ndarray):
batch[k] = np.stack([f[k] for f in features])
else:
batch[k] = np.array([f[k] for f in features])
return batch
[文档]@dataclass
class DefaultDataCollator(DataCollatorMixin):
"""
Very simple data collator that simply collates batches of dict-like objects and performs special handling for
potential keys named:
- `label`: handles a single value (int or float) per object
- `label_ids`: handles a list of values per object
Does not do any additional preprocessing: property names of the input object will be used as corresponding inputs
to the model. See glue and ner for example of how it's useful.
This is an object (like other data collators) rather than a pure function like default_data_collator. This can be
helpful if you need to set a return_tensors value at initialization.
Args:
return_tensors (`bool`):
Return Tensor or numpy array.
"""
return_tensors: str = "pd"
def __call__(self, features: List[Dict[str, Any]], return_tensors=None) -> Dict[str, Any]:
if return_tensors is None:
return_tensors = self.return_tensors
return default_data_collator(features, return_tensors)
[文档]@dataclass
class DataCollatorWithPadding:
"""
Data collator that will dynamically pad the inputs to the longest sequence in the batch.
Args:
tokenizer (`paddlenlp.transformers.PretrainedTokenizer`):
The tokenizer used for encoding the data.
"""
tokenizer: PretrainedTokenizerBase
padding: Union[bool, str, PaddingStrategy] = True
max_length: Optional[int] = None
pad_to_multiple_of: Optional[int] = None
return_tensors: str = "pd"
return_attention_mask: Optional[bool] = None
def __call__(self, features: List[Dict[str, Any]]) -> Dict[str, Any]:
batch = self.tokenizer.pad(
features,
padding=self.padding,
max_length=self.max_length,
pad_to_multiple_of=self.pad_to_multiple_of,
return_tensors=self.return_tensors,
return_attention_mask=self.return_attention_mask,
)
if "label" in batch:
batch["labels"] = batch["label"]
del batch["label"]
if "label_ids" in batch:
batch["labels"] = batch["label_ids"]
del batch["label_ids"]
# To fix windows bug for paddle inference dtype error
# InvalidArgumentError: The type of data we are trying to retrieve does not match the type of data currently contained in the container
if self.return_tensors == "np":
batch = {k: np.array(v, dtype=np.int64) for k, v in batch.items()}
return batch
[文档]@dataclass
class DataCollatorForTokenClassification(DataCollatorMixin):
"""
Data collator that will dynamically pad the inputs received, as well as the labels.
Args:
tokenizer ([`PretrainedTokenizer`] or [`PretrainedFasterTokenizer`]):
The tokenizer used for encoding the data.
padding (`bool`, `str` or [`~utils.PaddingStrategy`], *optional*, defaults to `True`):
Select a strategy to pad the returned sequences (according to the model's padding side and padding index)
among:
- `True` or `'longest'`: Pad to the longest sequence in the batch (or no padding if only a single sequence
is provided).
- `'max_length'`: Pad to a maximum length specified with the argument `max_length` or to the maximum
acceptable input length for the model if that argument is not provided.
- `False` or `'do_not_pad'` (default): No padding (i.e., can output a batch with sequences of different
lengths).
max_length (`int`, *optional*):
Maximum length of the returned list and optionally padding length (see above).
pad_to_multiple_of (`int`, *optional*):
If set will pad the sequence to a multiple of the provided value.
This is especially useful to enable the use of Tensor Cores on NVIDIA hardware with compute capability >=
7.5 (Volta).
label_pad_token_id (`int`, *optional*, defaults to -100):
The id to use when padding the labels (-100 will be automatically ignore by PaddlePaddle loss functions).
return_tensors (`str`):
The type of Tensor to return. Allowable values are "np", "pt" and "tf".
"""
tokenizer: PretrainedTokenizerBase
padding: Union[bool, str, PaddingStrategy] = True
max_length: Optional[int] = None
pad_to_multiple_of: Optional[int] = None
label_pad_token_id: int = -100
return_tensors: str = "pd"
def paddle_call(self, features):
label_name = "label" if "label" in features[0].keys() else "labels"
labels = [feature[label_name] for feature in features] if label_name in features[0].keys() else None
no_labels_features = [{k: v for k, v in feature.items() if k != label_name} for feature in features]
batch = self.tokenizer.pad(
no_labels_features,
padding=self.padding,
max_length=self.max_length,
pad_to_multiple_of=self.pad_to_multiple_of,
# Conversion to tensors will fail if we have labels as they are not of the same length yet.
return_tensors="pd" if labels is None else None,
)
if labels is None:
return batch
sequence_length = paddle.to_tensor(batch["input_ids"]).shape[1]
padding_side = self.tokenizer.padding_side
def to_list(tensor_or_iterable):
if isinstance(tensor_or_iterable, paddle.Tensor):
return tensor_or_iterable.tolist()
return list(tensor_or_iterable)
if padding_side == "right":
batch[label_name] = [
to_list(label) + [self.label_pad_token_id] * (sequence_length - len(label)) for label in labels
]
else:
batch[label_name] = [
[self.label_pad_token_id] * (sequence_length - len(label)) + to_list(label) for label in labels
]
batch = {k: paddle.to_tensor(v, dtype="int64") for k, v in batch.items()}
return batch
def numpy_call(self, features):
label_name = "label" if "label" in features[0].keys() else "labels"
labels = [feature[label_name] for feature in features] if label_name in features[0].keys() else None
batch = self.tokenizer.pad(
features,
padding=self.padding,
max_length=self.max_length,
pad_to_multiple_of=self.pad_to_multiple_of,
# Conversion to tensors will fail if we have labels as they are not of the same length yet.
return_tensors="np" if labels is None else None,
)
if labels is None:
return batch
sequence_length = np.array(batch["input_ids"]).shape[1]
padding_side = self.tokenizer.padding_side
if padding_side == "right":
batch["labels"] = [
list(label) + [self.label_pad_token_id] * (sequence_length - len(label)) for label in labels
]
else:
batch["labels"] = [
[self.label_pad_token_id] * (sequence_length - len(label)) + list(label) for label in labels
]
batch = {k: np.array(v, dtype=np.int64) for k, v in batch.items()}
return batch
[文档]@dataclass
class DataCollatorForSeq2Seq:
"""
Data collator that will dynamically pad the inputs received, as well as the labels.
Args:
tokenizer ([`PretrainedTokenizer`] or [`PretrainedFasterTokenizer`]):
The tokenizer used for encoding the data.
model ([`PreTrainedModel`]):
The model that is being trained. If set and has the *prepare_decoder_input_ids_from_labels*, use it to
prepare the *decoder_input_ids*
This is useful when using *label_smoothing* to avoid calculating loss twice.
padding (`bool`, `str` or [`~utils.PaddingStrategy`], *optional*, defaults to `True`):
Select a strategy to pad the returned sequences (according to the model's padding side and padding index)
among:
- `True` or `'longest'`: Pad to the longest sequence in the batch (or no padding if only a single sequence
is provided).
- `'max_length'`: Pad to a maximum length specified with the argument `max_length` or to the maximum
acceptable input length for the model if that argument is not provided.
- `False` or `'do_not_pad'` (default): No padding (i.e., can output a batch with sequences of different
lengths).
max_length (`int`, *optional*):
Maximum length of the returned list and optionally padding length (see above).
pad_to_multiple_of (`int`, *optional*):
If set will pad the sequence to a multiple of the provided value.
This is especially useful to enable the use of Tensor Cores on NVIDIA hardware with compute capability >=
7.5 (Volta).
label_pad_token_id (`int`, *optional*, defaults to -100):
The id to use when padding the labels (-100 will be automatically ignored by PaddlePaddle loss functions).
return_tensors (`str`):
The type of Tensor to return. Allowable values are "np", "pt" and "tf".
"""
tokenizer: PretrainedTokenizerBase
model: Optional[Any] = None
padding: Union[bool, str, PaddingStrategy] = True
max_length: Optional[int] = None
pad_to_multiple_of: Optional[int] = None
label_pad_token_id: int = -100
return_tensors: str = "pd"
def __call__(self, features, return_tensors=None):
if return_tensors is None:
return_tensors = self.return_tensors
labels = [feature["labels"] for feature in features] if "labels" in features[0].keys() else None
# We have to pad the labels before calling `tokenizer.pad` as this method won't pad them and needs them of the
# same length to return tensors.
if labels is not None:
max_label_length = max(len(l) for l in labels)
if self.pad_to_multiple_of is not None:
max_label_length = (
(max_label_length + self.pad_to_multiple_of - 1)
// self.pad_to_multiple_of
* self.pad_to_multiple_of
)
padding_side = self.tokenizer.padding_side
for feature in features:
remainder = [self.label_pad_token_id] * (max_label_length - len(feature["labels"]))
if isinstance(feature["labels"], list):
feature["labels"] = (
feature["labels"] + remainder if padding_side == "right" else remainder + feature["labels"]
)
elif padding_side == "right":
feature["labels"] = np.concatenate([feature["labels"], remainder]).astype(np.int64)
else:
feature["labels"] = np.concatenate([remainder, feature["labels"]]).astype(np.int64)
features = self.tokenizer.pad(
features,
padding=self.padding,
max_length=self.max_length,
pad_to_multiple_of=self.pad_to_multiple_of,
return_tensors=return_tensors,
)
# prepare decoder_input_ids
if (
labels is not None
and self.model is not None
and hasattr(self.model, "prepare_decoder_input_ids_from_labels")
):
decoder_input_ids = self.model.prepare_decoder_input_ids_from_labels(labels=features["labels"])
features["decoder_input_ids"] = decoder_input_ids
return features
def _paddle_collate_batch(examples, tokenizer, pad_to_multiple_of: Optional[int] = None):
"""Collate `examples` into a batch, using the information in `tokenizer` for padding if necessary."""
import paddle
# Tensorize if necessary.
if isinstance(examples[0], (list, tuple, np.ndarray)):
examples = [paddle.to_tensor(e, dtype="int64") for e in examples]
length_of_first = examples[0].shape[0]
# Check if padding is necessary.
are_tensors_same_length = all(x.shape[0] == length_of_first for x in examples)
if are_tensors_same_length and (pad_to_multiple_of is None or length_of_first % pad_to_multiple_of == 0):
return paddle.stack(examples, axis=0)
# If yes, check if we have a `pad_token`.
if tokenizer._pad_token is None:
raise ValueError(
"You are attempting to pad samples but the tokenizer you are using"
f" ({tokenizer.__class__.__name__}) does not have a pad token."
)
# Creating the full tensor and filling it with our data.
max_length = max(x.shape[0] for x in examples)
if pad_to_multiple_of is not None and (max_length % pad_to_multiple_of != 0):
max_length = ((max_length // pad_to_multiple_of) + 1) * pad_to_multiple_of
# result = examples[0].new_full([len(examples), max_length], tokenizer.pad_token_id)
result = paddle.full([len(examples), max_length], tokenizer.pad_token_id, dtype=examples[0].dtype)
for i, example in enumerate(examples):
if tokenizer.padding_side == "right":
result[i, : example.shape[0]] = example
else:
result[i, -example.shape[0] :] = example
return result
def _numpy_collate_batch(examples, tokenizer, pad_to_multiple_of: Optional[int] = None):
import numpy as np
"""Collate `examples` into a batch, using the information in `tokenizer` for padding if necessary."""
# Tensorize if necessary.
if isinstance(examples[0], (list, tuple)):
examples = [np.array(e, dtype=np.int64) for e in examples]
# Check if padding is necessary.
length_of_first = len(examples[0])
are_tensors_same_length = all(len(x) == length_of_first for x in examples)
if are_tensors_same_length and (pad_to_multiple_of is None or length_of_first % pad_to_multiple_of == 0):
return np.stack(examples, axis=0)
# If yes, check if we have a `pad_token`.
if tokenizer._pad_token is None:
raise ValueError(
"You are attempting to pad samples but the tokenizer you are using"
f" ({tokenizer.__class__.__name__}) does not have a pad token."
)
# Creating the full tensor and filling it with our data.
max_length = max(len(x) for x in examples)
if pad_to_multiple_of is not None and (max_length % pad_to_multiple_of != 0):
max_length = ((max_length // pad_to_multiple_of) + 1) * pad_to_multiple_of
result = np.full(shape=(len(examples), max_length), fill_value=tokenizer.pad_token_id, dtype=examples[0].dtype)
for i, example in enumerate(examples):
if tokenizer.padding_side == "right":
result[i, : example.shape[0]] = example
else:
result[i, -example.shape[0] :] = example
return result
def tolist(x):
if isinstance(x, list):
return x
elif hasattr(x, "numpy"): # Checks for TF tensors without needing the import
x = x.numpy()
return x.tolist()
[文档]@dataclass
class DataCollatorForLanguageModeling(DataCollatorMixin):
"""
Data collator used for language modeling. Inputs are dynamically padded to the maximum length of a batch if they
are not all of the same length.
Args:
tokenizer ([`PreTrainedTokenizer`] or [`PreTrainedTokenizerFast`]):
The tokenizer used for encoding the data.
mlm (`bool`, *optional*, defaults to `True`):
Whether or not to use masked language modeling. If set to `False`, the labels are the same as the inputs
with the padding tokens ignored (by setting them to -100). Otherwise, the labels are -100 for non-masked
tokens and the value to predict for the masked token.
mlm_probability (`float`, *optional*, defaults to 0.15):
The probability with which to (randomly) mask tokens in the input, when `mlm` is set to `True`.
pad_to_multiple_of (`int`, *optional*):
If set will pad the sequence to a multiple of the provided value.
return_tensors (`str`):
The type of Tensor to return. Allowable values are "np", "pt" and "tf".
<Tip>
For best performance, this data collator should be used with a dataset having items that are dictionaries or
BatchEncoding, with the `"special_tokens_mask"` key, as returned by a [`PreTrainedTokenizer`] or a
[`PreTrainedTokenizerFast`] with the argument `return_special_tokens_mask=True`.
</Tip>"""
tokenizer: PretrainedTokenizerBase
mlm: bool = True
mlm_probability: float = 0.15
pad_to_multiple_of: Optional[int] = None
return_tensors: str = "pd"
def paddle_call(self, examples: List[Union[List[int], Any, Dict[str, Any]]]) -> Dict[str, Any]:
# Handle dict or lists with proper padding and conversion to tensor.
if isinstance(examples[0], Mapping):
batch = self.tokenizer.pad(examples, return_tensors="pd", pad_to_multiple_of=self.pad_to_multiple_of)
else:
batch = {
"input_ids": _paddle_collate_batch(
examples, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of
)
}
# If special token mask has been preprocessed, pop it from the dict.
special_tokens_mask = batch.pop("special_tokens_mask", None)
if self.mlm:
batch["input_ids"], batch["labels"] = self.paddle_mask_tokens(
batch["input_ids"], special_tokens_mask=special_tokens_mask
)
else:
labels = batch["input_ids"].clone()
if self.tokenizer.pad_token_id is not None:
labels[labels == self.tokenizer.pad_token_id] = -100
batch["labels"] = labels
return batch
[文档] def paddle_mask_tokens(self, inputs: Any, special_tokens_mask: Optional[Any] = None) -> Tuple[Any, Any]:
"""
Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original.
"""
import paddle
labels = inputs.clone()
# We sample a few tokens in each sequence for MLM training (with probability `self.mlm_probability`)
probability_matrix = paddle.full(labels.shape, self.mlm_probability)
if special_tokens_mask is None:
special_tokens_mask = [
self.tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True) for val in labels.tolist()
]
special_tokens_mask = paddle.to_tensor(special_tokens_mask, dtype="bool")
else:
special_tokens_mask = special_tokens_mask.cast("bool")
def masked_fill(x, mask, value):
y = paddle.full(x.shape, value, x.dtype)
return paddle.where(mask, y, x)
# probability_matrix.masked_fill_(special_tokens_mask, value=0.0)
probability_matrix = masked_fill(probability_matrix, special_tokens_mask, value=0.0)
masked_indices = paddle.bernoulli(probability_matrix).cast("bool")
labels[~masked_indices] = -100 # We only compute loss on masked tokens
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = paddle.bernoulli(paddle.full(labels.shape, 0.8)).cast("bool") & masked_indices
inputs[indices_replaced] = self.tokenizer.convert_tokens_to_ids(self.tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
indices_random = (
paddle.bernoulli(paddle.full(labels.shape, 0.5)).cast("bool") & masked_indices & ~indices_replaced
)
random_words = paddle.randint(len(self.tokenizer), shape=labels.shape, dtype="int64")
inputs[indices_random] = random_words[indices_random]
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels
def numpy_call(self, examples: List[Union[List[int], Any, Dict[str, Any]]]) -> Dict[str, Any]:
# Handle dict or lists with proper padding and conversion to tensor.
if isinstance(examples[0], Mapping):
batch = self.tokenizer.pad(examples, return_tensors="np", pad_to_multiple_of=self.pad_to_multiple_of)
else:
batch = {
"input_ids": _numpy_collate_batch(examples, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of)
}
# If special token mask has been preprocessed, pop it from the dict.
special_tokens_mask = batch.pop("special_tokens_mask", None)
if self.mlm:
batch["input_ids"], batch["labels"] = self.numpy_mask_tokens(
batch["input_ids"], special_tokens_mask=special_tokens_mask
)
else:
labels = np.copy(batch["input_ids"])
if self.tokenizer.pad_token_id is not None:
labels[labels == self.tokenizer.pad_token_id] = -100
batch["labels"] = labels
return batch
[文档] def numpy_mask_tokens(self, inputs: Any, special_tokens_mask: Optional[Any] = None) -> Tuple[Any, Any]:
"""
Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original.
"""
labels = np.copy(inputs)
# We sample a few tokens in each sequence for MLM training (with probability `self.mlm_probability`)
probability_matrix = np.full(labels.shape, self.mlm_probability)
if special_tokens_mask is None:
special_tokens_mask = [
self.tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True) for val in labels.tolist()
]
special_tokens_mask = np.array(special_tokens_mask, dtype=bool)
else:
special_tokens_mask = special_tokens_mask.astype(bool)
probability_matrix[special_tokens_mask] = 0
# Numpy doesn't have bernoulli, so we use a binomial with 1 trial
masked_indices = np.random.binomial(1, probability_matrix, size=probability_matrix.shape).astype(bool)
labels[~masked_indices] = -100 # We only compute loss on masked tokens
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = np.random.binomial(1, 0.8, size=labels.shape).astype(bool) & masked_indices
inputs[indices_replaced] = self.tokenizer.mask_token_id
# 10% of the time, we replace masked input tokens with random word
# indices_random = paddle.bernoulli(paddle.full(labels.shape, 0.5)).bool() & masked_indices & ~indices_replaced
indices_random = (
np.random.binomial(1, 0.5, size=labels.shape).astype(bool) & masked_indices & ~indices_replaced
)
random_words = np.random.randint(
low=0, high=len(self.tokenizer), size=np.count_nonzero(indices_random), dtype=np.int64
)
inputs[indices_random] = random_words
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels
[文档]@dataclass
class DataCollatorForWholeWordMask(DataCollatorForLanguageModeling):
"""
Data collator used for language modeling that masks entire words.
- collates batches of tensors, honoring their tokenizer's pad_token
- preprocesses batches for masked language modeling
<Tip>
This collator relies on details of the implementation of subword tokenization by [`BertTokenizer`], specifically
that subword tokens are prefixed with *##*. For tokenizers that do not adhere to this scheme, this collator will
produce an output that is roughly equivalent to [`.DataCollatorForLanguageModeling`].
</Tip>"""
def paddle_call(self, examples: List[Union[List[int], Any, Dict[str, Any]]]) -> Dict[str, Any]:
if isinstance(examples[0], Mapping):
input_ids = [e["input_ids"] for e in examples]
else:
input_ids = examples
examples = [{"input_ids": e} for e in examples]
batch_input = _paddle_collate_batch(input_ids, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of)
mask_labels = []
for e in examples:
ref_tokens = []
for id in tolist(e["input_ids"]):
token = self.tokenizer._convert_id_to_token(id)
ref_tokens.append(token)
# For Chinese tokens, we need extra inf to mark sub-word, e.g [喜,欢]-> [喜，##欢]
if "chinese_ref" in e:
ref_pos = tolist(e["chinese_ref"])
len_seq = len(e["input_ids"])
for i in range(len_seq):
if i in ref_pos:
ref_tokens[i] = "##" + ref_tokens[i]
mask_labels.append(self._whole_word_mask(ref_tokens))
batch_mask = _paddle_collate_batch(mask_labels, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of)
inputs, labels = self.paddle_mask_tokens(batch_input, batch_mask)
return {"input_ids": inputs, "labels": labels}
def numpy_call(self, examples: List[Union[List[int], Any, Dict[str, Any]]]) -> Dict[str, Any]:
if isinstance(examples[0], Mapping):
input_ids = [e["input_ids"] for e in examples]
else:
input_ids = examples
examples = [{"input_ids": e} for e in examples]
batch_input = _numpy_collate_batch(input_ids, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of)
mask_labels = []
for e in examples:
ref_tokens = []
for id in tolist(e["input_ids"]):
token = self.tokenizer._convert_id_to_token(id)
ref_tokens.append(token)
# For Chinese tokens, we need extra inf to mark sub-word, e.g [喜,欢]-> [喜，##欢]
if "chinese_ref" in e:
ref_pos = tolist(e["chinese_ref"])
len_seq = len(e["input_ids"])
for i in range(len_seq):
if i in ref_pos:
ref_tokens[i] = "##" + ref_tokens[i]
mask_labels.append(self._whole_word_mask(ref_tokens))
batch_mask = _numpy_collate_batch(mask_labels, self.tokenizer, pad_to_multiple_of=self.pad_to_multiple_of)
inputs, labels = self.numpy_mask_tokens(batch_input, batch_mask)
return {"input_ids": inputs, "labels": labels}
def _whole_word_mask(self, input_tokens: List[str], max_predictions=512):
"""
Get 0/1 labels for masked tokens with whole word mask proxy
"""
if not isinstance(self.tokenizer, (BertTokenizer)):
warnings.warn(
"DataCollatorForWholeWordMask is only suitable for BertTokenizer-like tokenizers. "
"Please refer to the documentation for more information."
)
cand_indexes = []
for i, token in enumerate(input_tokens):
if token == "[CLS]" or token == "[SEP]":
continue
if len(cand_indexes) >= 1 and token.startswith("##"):
cand_indexes[-1].append(i)
else:
cand_indexes.append([i])
random.shuffle(cand_indexes)
num_to_predict = min(max_predictions, max(1, int(round(len(input_tokens) * self.mlm_probability))))
masked_lms = []
covered_indexes = set()
for index_set in cand_indexes:
if len(masked_lms) >= num_to_predict:
break
# If adding a whole-word mask would exceed the maximum number of
# predictions, then just skip this candidate.
if len(masked_lms) + len(index_set) > num_to_predict:
continue
is_any_index_covered = False
for index in index_set:
if index in covered_indexes:
is_any_index_covered = True
break
if is_any_index_covered:
continue
for index in index_set:
covered_indexes.add(index)
masked_lms.append(index)
if len(covered_indexes) != len(masked_lms):
raise ValueError("Length of covered_indexes is not equal to length of masked_lms.")
mask_labels = [1 if i in covered_indexes else 0 for i in range(len(input_tokens))]
return mask_labels
[文档] def paddle_mask_tokens(self, inputs: Any, mask_labels: Any) -> Tuple[Any, Any]:
"""
Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. Set
'mask_labels' means we use whole word mask (wwm), we directly mask idxs according to it's ref.
"""
import paddle
if self.tokenizer.mask_token is None:
raise ValueError(
"This tokenizer does not have a mask token which is necessary for masked language modeling. Remove the"
" --mlm flag if you want to use this tokenizer."
)
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)
probability_matrix = mask_labels
special_tokens_mask = [
self.tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True) for val in labels.tolist()
]
def masked_fill(x, mask, value):
y = paddle.full(x.shape, value, x.dtype)
return paddle.where(mask, y, x)
# probability_matrix.masked_fill_(paddle.tensor(special_tokens_mask, dtype=paddle.bool), value=0.0)
probability_matrix = masked_fill(
probability_matrix, paddle.to_tensor(special_tokens_mask, dtype="bool"), value=0.0
)
if self.tokenizer._pad_token is not None:
padding_mask = labels.equal(self.tokenizer.pad_token_id)
# probability_matrix.masked_fill_(padding_mask, value=0.0)
probability_matrix = masked_fill(probability_matrix, padding_mask, value=0.0)
masked_indices = probability_matrix.cast("bool")
labels[~masked_indices] = -100 # We only compute loss on masked tokens
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = paddle.bernoulli(paddle.full(labels.shape, 0.8)).cast("bool") & masked_indices
inputs[indices_replaced] = self.tokenizer.convert_tokens_to_ids(self.tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
indices_random = (
paddle.bernoulli(paddle.full(labels.shape, 0.5)).cast("bool") & masked_indices & ~indices_replaced
)
random_words = paddle.randint(0, len(self.tokenizer), labels.shape, dtype="int64")
inputs[indices_random] = random_words[indices_random]
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels
[文档] def numpy_mask_tokens(self, inputs: Any, mask_labels: Any) -> Tuple[Any, Any]:
"""
Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. Set
'mask_labels' means we use whole word mask (wwm), we directly mask idxs according to it's ref.
"""
if self.tokenizer.mask_token is None:
raise ValueError(
"This tokenizer does not have a mask token which is necessary for masked language modeling. Remove the"
" --mlm flag if you want to use this tokenizer."
)
labels = np.copy(inputs)
# 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 = mask_labels.astype(bool)
special_tokens_mask = [
self.tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True) for val in labels.tolist()
]
masked_indices[np.array(special_tokens_mask, dtype=bool)] = 0
if self.tokenizer._pad_token is not None:
padding_mask = labels == self.tokenizer.pad_token_id
masked_indices[padding_mask] = 0
labels[~masked_indices] = -100 # We only compute loss on masked tokens
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = np.random.binomial(1, 0.8, size=labels.shape).astype(bool) & masked_indices
inputs[indices_replaced] = self.tokenizer.convert_tokens_to_ids(self.tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
# indices_random = paddle.bernoulli(paddle.full(labels.shape, 0.5)).bool() & masked_indices & ~indices_replaced
indices_random = (
np.random.binomial(1, 0.5, size=labels.shape).astype(bool) & masked_indices & ~indices_replaced
)
random_words = np.random.randint(low=0, high=len(self.tokenizer), size=labels.shape, dtype=np.int64)
inputs[indices_random] = random_words[indices_random]
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels