paddlenlp.transformers.bart.tokenizer 源代码

# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2020 The Facebook AI Research Team Authors and The HuggingFace Inc. team.
# Licensed under the Apache License, Version 2.0 (the "License");
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from paddle.utils import try_import
from .. import GPTTokenizer, AddedToken

__all__ = ['BartTokenizer']

[文档]class BartTokenizer(GPTTokenizer): r""" Construct a BART tokenizer based on byte-level Byte-Pair-Encoding. This tokenizer inherits from :class:`~paddlenlp.transformers.gpt.tokenizer.GPTTokenizer`. For more information regarding those methods, please refer to this superclass. Args: vocab_file (str): Path to the vocabulary file. The vocab file contains a mapping from vocabulary strings to indices. merges_file (str): Path to the merge file. The merge file is used to split the input sentence into "subword" units. The vocab file is then used to encode those units as intices. errors (str): Paradigm to follow when decoding bytes to UTF-8. Defaults to `'replace'`. max_len (int, optional): The maximum value of the input sequence length. Defaults to `None`. bos_token (str, optional): The beginning of sequence token that was used during pretraining. Can be used a sequence classifier token. Defaults to `"<s>"`. eos_token (str, optional): A special token representing the end of a sequence that was used during pretraining. Defaults to `"</s>"`. cls_token (str, optional): A special token used for sequence classification. It is the last token of the sequence when built with special tokens. Defaults to `"<s>"`. sep_token (str, optional): A special token separating two different sentences in the same input. Defaults to `"</s>"`. unk_token (str, optional): A special token representing the *unknown (out-of-vocabulary)* token. An unknown token is set to be `unk_token` inorder to be converted to an ID. Defaults to `"<unk>"`. pad_token (str, optional): A special token used to make arrays of tokens the same size for batching purposes. Defaults to `"<pad>"`. mask_token (str, optional): A special token representing a masked token. This is the token used in the masked language modeling task which the model tries to predict the original unmasked ones. Defaults to `"<mask>"`. Examples: .. code-block:: from paddlenlp.transformers import BartTokenizer tokenizer = BartTokenizer.from_pretrained('bart-base') print(tokenizer('He was a puppeteer')) ''' {'input_ids': [0, 894, 21, 10, 32986, 9306, 254, 2], 'attention_mask': [1, 1, 1, 1, 1, 1, 1, 1]} ''' """ # merges and vocab same as GPT2 resource_files_names = { "vocab_file": "vocab.json", "merges_file": "merges.txt" } pretrained_resource_files_map = { "vocab_file": { "bart-base": "", "bart-large": "", }, "merges_file": { "bart-base": "", "bart-large": "", } } pretrained_init_configuration = {"bart-base": {}, "bart-large": {}} def __init__(self, vocab_file, merges_file, errors='replace', max_len=None, bos_token="<s>", eos_token="</s>", cls_token="<s>", sep_token="</s>", unk_token="<unk>", pad_token="<pad>", mask_token="<mask>", **kwargs): bos_token = AddedToken( bos_token, lstrip=False, rstrip=False) if isinstance(bos_token, str) else bos_token eos_token = AddedToken( eos_token, lstrip=False, rstrip=False) if isinstance(eos_token, str) else eos_token sep_token = AddedToken( sep_token, lstrip=False, rstrip=False) if isinstance(sep_token, str) else sep_token cls_token = AddedToken( cls_token, lstrip=False, rstrip=False) if isinstance(cls_token, str) else cls_token unk_token = AddedToken( unk_token, lstrip=False, rstrip=False) if isinstance(unk_token, str) else unk_token pad_token = AddedToken( pad_token, lstrip=False, rstrip=False) if isinstance(pad_token, str) else pad_token # Mask token behave like a normal word, i.e. include the space before it mask_token = AddedToken( mask_token, lstrip=True, rstrip=False) if isinstance(mask_token, str) else mask_token self._build_special_tokens_map_extended( bos_token=bos_token, eos_token=eos_token, sep_token=sep_token, cls_token=cls_token, unk_token=unk_token, pad_token=pad_token, mask_token=mask_token) super(BartTokenizer, self).__init__(vocab_file, merges_file, errors, max_len, pad_token, eos_token) def _bpe_encode(self, text): bpe_tokens = [] re = try_import("regex") for token in re.findall(self.pat, text): token = ''.join(self.byte_encoder[b] for b in token.encode('utf-8')) bpe_tokens.extend( bpe_token for bpe_token in self.bpe(token).split(' ')) return bpe_tokens
[文档] 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. """ _cls = [self.cls_token_id] _sep = [self.sep_token_id] if token_ids_1 is None: return _cls + token_ids_0 + _sep return _cls + token_ids_0 + _sep + _sep + token_ids_1 + _sep
[文档] 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 ``encode`` methods. """ if already_has_special_tokens: return super().get_special_tokens_mask( token_ids_0=token_ids_0, token_ids_1=token_ids_1, already_has_special_tokens=True) 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]
[文档] def create_token_type_ids_from_sequences(self, token_ids_0, token_ids_1=None): """ Create a mask from the two sequences passed to be used in a sequence-pair classification task. """ 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 + sep + token_ids_1 + sep) * [0]