[T5Tokenizer] add prepare_seq2seq_batch method (#6122)

* tests
This commit is contained in:
Suraj Patil
2020-08-17 23:27:19 +05:30
committed by GitHub
parent c9564f5343
commit 407da12ef1
2 changed files with 206 additions and 1 deletions

View File

@@ -19,8 +19,9 @@ import logging
import os
import re
from shutil import copyfile
from typing import List, Optional
from .tokenization_utils import PreTrainedTokenizer
from .tokenization_utils import BatchEncoding, PreTrainedTokenizer
logger = logging.getLogger(__name__)
@@ -96,6 +97,8 @@ class T5Tokenizer(PreTrainedTokenizer):
max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
model_input_names = ["attention_mask"]
prefix_tokens: List[int] = []
def __init__(
self,
vocab_file,
@@ -206,3 +209,127 @@ class T5Tokenizer(PreTrainedTokenizer):
copyfile(self.vocab_file, out_vocab_file)
return (out_vocab_file,)
def build_inputs_with_special_tokens(
self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
) -> List[int]:
"""
Build model inputs from a sequence or a pair of sequence for sequence classification tasks
by concatenating and adding special tokens. The special tokens depend on calling source text or target text.
A T5 sequence has the following format, where ``X`` represents the sequence:
- ``input_ids`` (for encoder) ``X [eos]``
- ``decoder_input_ids``: (for decoder) ``[pad] X [eos]``
Pairs of sequences are not the expected use case, but they will be handled without a separator.
Args:
token_ids_0 (:obj:`List[int]`):
List of IDs to which the special tokens will be added
token_ids_1 (:obj:`List[int]`, `optional`):
Optional second list of IDs for sequence pairs.
Returns:
:obj:`List[int]`: List of `input IDs <../glossary.html#input-ids>`__ with the appropriate special tokens.
"""
if token_ids_1 is None:
return self.prefix_tokens + token_ids_0
# We don't expect to process pairs, but leave the pair logic for API consistency
return self.prefix_tokens + token_ids_0 + token_ids_1
def prepare_seq2seq_batch(
self,
src_texts: List[str],
tgt_texts: Optional[List[str]] = None,
max_length: Optional[int] = None,
max_target_length: Optional[int] = None,
padding: str = "longest",
return_tensors: str = None,
truncation: bool = True,
**kwargs,
) -> BatchEncoding:
r"""
Prepare a batch that can be passed directly to an instance of :class:`~transformers.T5Model`.
Args:
src_texts: (:obj:`List[str]`):
List of documents to summarize or source language texts.
tgt_texts: (:obj:`List[str]`, `optional`):
List of summaries or target language texts.
max_length (:obj:`int`, `optional`):
Controls the maximum length for encoder inputs (documents to summarize or source language texts).
If left unset or set to :obj:`None`, this will use the predefined model maximum length if a maximum
length is required by one of the truncation/padding parameters. If the model has no specific maximum
input length (like XLNet) truncation/padding to a maximum length will be deactivated.
max_target_length (:obj:`int`, `optional`):
Controls the maximum length of decoder inputs (target language texts or summaries).
If left unset or set to :obj:`None`, this will use the max_length value.
padding (:obj:`bool`, :obj:`str` or :class:`~transformers.tokenization_utils_base.PaddingStrategy`, `optional`, defaults to :obj:`False`):
Activates and controls padding. Accepts the following values:
* :obj:`True` or :obj:`'longest'`: Pad to the longest sequence in the batch (or no padding if only a
single sequence if provided).
* :obj:`'max_length'`: Pad to a maximum length specified with the argument :obj:`max_length` or to the
maximum acceptable input length for the model if that argument is not provided.
* :obj:`False` or :obj:`'do_not_pad'` (default): No padding (i.e., can output a batch with sequences of
different lengths).
return_tensors (:obj:`str` or :class:`~transformers.tokenization_utils_base.TensorType`, `optional`, defaults to "pt"):
If set, will return tensors instead of list of python integers. Acceptable values are:
* :obj:`'tf'`: Return TensorFlow :obj:`tf.constant` objects.
* :obj:`'pt'`: Return PyTorch :obj:`torch.Tensor` objects.
* :obj:`'np'`: Return Numpy :obj:`np.ndarray` objects.
truncation (:obj:`bool`, :obj:`str` or :class:`~transformers.tokenization_utils_base.TruncationStrategy`, `optional`, defaults to :obj:`True`):
Activates and controls truncation. Accepts the following values:
* :obj:`True` or :obj:`'longest_first'`: Truncate to a maximum length specified with the argument
:obj:`max_length` or to the maximum acceptable input length for the model if that argument is not
provided. This will truncate token by token, removing a token from the longest sequence in the pair
if a pair of sequences (or a batch of pairs) is provided.
* :obj:`'only_first'`: Truncate to a maximum length specified with the argument :obj:`max_length` or to
the maximum acceptable input length for the model if that argument is not provided. This will only
truncate the first sequence of a pair if a pair of sequences (or a batch of pairs) is provided.
* :obj:`'only_second'`: Truncate to a maximum length specified with the argument :obj:`max_length` or
to the maximum acceptable input length for the model if that argument is not provided. This will only
truncate the second sequence of a pair if a pair of sequences (or a batch of pairs) is provided.
* :obj:`False` or :obj:`'do_not_truncate'` (default): No truncation (i.e., can output batch with
sequence lengths greater than the model maximum admissible input size).
**kwargs:
Additional keyword arguments passed along to :obj:`self.__call__`.
Returns:
:class:`~transformers.BatchEncoding`: A :class:`~transformers.BatchEncoding` with the following fields:
- **input_ids** -- List of token ids to be fed to the encoder.
- **attention_mask** -- List of indices specifying which tokens should be attended to by the model.
- **decoder_input_ids** -- List of token ids to be fed to the decoder.
- **decoder_attention_mask** -- List of indices specifying which tokens should be attended to by the decoder.
This does not include causal mask, which is built by the model.
The full set of keys ``[input_ids, attention_mask, decoder_input_ids, decoder_attention_mask]``,
will only be returned if tgt_texts is passed. Otherwise, input_ids, attention_mask will be the only keys.
"""
if max_length is None:
max_length = self.max_len
self.prefix_tokens = []
model_inputs: BatchEncoding = self(
src_texts,
add_special_tokens=True,
return_tensors=return_tensors,
max_length=max_length,
padding=padding,
truncation=truncation,
**kwargs,
)
if tgt_texts is None:
return model_inputs
# Process tgt_texts
if max_target_length is None:
max_target_length = max_length
# set prefix_tokens for target text
self.prefix_tokens = [self.pad_token_id]
decoder_inputs: BatchEncoding = self(
tgt_texts,
add_special_tokens=True,
return_tensors=return_tensors,
padding=padding,
max_length=max_target_length,
truncation=truncation,
**kwargs,
)
for k, v in decoder_inputs.items():
model_inputs[f"decoder_{k}"] = v
self.prefix_tokens = []
return model_inputs