Source code for transformers.models.mbart.tokenization_mbart50_fast

# coding=utf-8
# Copyright 2021 The Facebook AI Research Team Authors and The HuggingFace Inc. team.
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#     http://www.apache.org/licenses/LICENSE-2.0
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import os
from contextlib import contextmanager
from shutil import copyfile
from typing import List, Optional, Tuple

from tokenizers import processors

from ...file_utils import is_sentencepiece_available
from ...tokenization_utils import AddedToken, BatchEncoding
from ...tokenization_utils_fast import PreTrainedTokenizerFast
from ...utils import logging


if is_sentencepiece_available():
    from .tokenization_mbart50 import MBart50Tokenizer
else:
    MBart50Tokenizer = None


logger = logging.get_logger(__name__)

VOCAB_FILES_NAMES = {"vocab_file": "sentencepiece.bpe.model", "tokenizer_file": "tokenizer.json"}

PRETRAINED_VOCAB_FILES_MAP = {
    "vocab_file": {
        "facebook/mbart-large-50-one-to-many-mmt": "https://huggingface.co/facebook/mbart-large-50-one-to-many-mmt/resolve/main/sentencepiece.bpe.model",
    },
    "tokenizer_file": {
        "facebook/mbart-large-50-one-to-many-mmt": "https://huggingface.co/facebook/mbart-large-50-one-to-many-mmt/resolve/main/tokenizer.json",
    },
}

PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
    "facebook/mbart-large-50-one-to-many-mmt": 1024,
}

# fmt: off
FAIRSEQ_LANGUAGE_CODES = ["ar_AR", "cs_CZ", "de_DE", "en_XX", "es_XX", "et_EE", "fi_FI", "fr_XX", "gu_IN", "hi_IN", "it_IT", "ja_XX", "kk_KZ", "ko_KR", "lt_LT", "lv_LV", "my_MM", "ne_NP", "nl_XX", "ro_RO", "ru_RU", "si_LK", "tr_TR", "vi_VN", "zh_CN", "af_ZA", "az_AZ", "bn_IN", "fa_IR", "he_IL", "hr_HR", "id_ID", "ka_GE", "km_KH", "mk_MK", "ml_IN", "mn_MN", "mr_IN", "pl_PL", "ps_AF", "pt_XX", "sv_SE", "sw_KE", "ta_IN", "te_IN", "th_TH", "tl_XX", "uk_UA", "ur_PK", "xh_ZA", "gl_ES", "sl_SI"]
# fmt: on


[docs]class MBart50TokenizerFast(PreTrainedTokenizerFast): """ Construct a "fast" MBART tokenizer for mBART-50 (backed by HuggingFace's `tokenizers` library). Based on `BPE <https://huggingface.co/docs/tokenizers/python/latest/components.html?highlight=BPE#models>`__. This tokenizer inherits from :class:`~transformers.PreTrainedTokenizerFast` which contains most of the main methods. Users should refer to this superclass for more information regarding those methods. Args: vocab_file (:obj:`str`): Path to the vocabulary file. src_lang (:obj:`str`, `optional`): A string representing the source language. tgt_lang (:obj:`str`, `optional`): A string representing the target language. eos_token (:obj:`str`, `optional`, defaults to :obj:`"</s>"`): The end of sequence token. sep_token (:obj:`str`, `optional`, defaults to :obj:`"</s>"`): The separator token, which is used when building a sequence from multiple sequences, e.g. two sequences for sequence classification or for a text and a question for question answering. It is also used as the last token of a sequence built with special tokens. cls_token (:obj:`str`, `optional`, defaults to :obj:`"<s>"`): The classifier token which is used when doing sequence classification (classification of the whole sequence instead of per-token classification). It is the first token of the sequence when built with special tokens. unk_token (:obj:`str`, `optional`, defaults to :obj:`"<unk>"`): The unknown token. A token that is not in the vocabulary cannot be converted to an ID and is set to be this token instead. pad_token (:obj:`str`, `optional`, defaults to :obj:`"<pad>"`): The token used for padding, for example when batching sequences of different lengths. mask_token (:obj:`str`, `optional`, defaults to :obj:`"<mask>"`): The token used for masking values. This is the token used when training this model with masked language modeling. This is the token which the model will try to predict. Examples:: >>> from transformers import MBart50TokenizerFast >>> tokenizer = MBart50TokenizerFast.from_pretrained("facebook/mbart-large-50", src_lang="en_XX", tgt_lang="ro_RO") >>> src_text = " UN Chief Says There Is No Military Solution in Syria" >>> tgt_text = "Şeful ONU declară că nu există o soluţie militară în Siria" >>> model_inputs = tokenizer(src_text, return_tensors="pt") >>> with tokenizer.as_target_tokenizer(): ... labels = tokenizer(tgt_text, return_tensors="pt").input_ids >>> # model(**model_inputs, labels=labels) should work """ vocab_files_names = VOCAB_FILES_NAMES max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP model_input_names = ["input_ids", "attention_mask"] slow_tokenizer_class = MBart50Tokenizer prefix_tokens: List[int] = [] suffix_tokens: List[int] = [] def __init__( self, vocab_file, src_lang=None, tgt_lang=None, tokenizer_file=None, eos_token="</s>", sep_token="</s>", cls_token="<s>", unk_token="<unk>", pad_token="<pad>", mask_token="<mask>", **kwargs ): # 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 super().__init__( vocab_file, src_lang=src_lang, tgt_lang=tgt_lang, tokenizer_file=tokenizer_file, eos_token=eos_token, sep_token=sep_token, cls_token=cls_token, unk_token=unk_token, pad_token=pad_token, mask_token=mask_token, **kwargs, ) self.vocab_file = vocab_file self.add_special_tokens({"additional_special_tokens": FAIRSEQ_LANGUAGE_CODES}) self.lang_code_to_id = { lang_code: self.convert_tokens_to_ids(lang_code) for lang_code in FAIRSEQ_LANGUAGE_CODES } self._src_lang = src_lang if src_lang is not None else "en_XX" self.tgt_lang = tgt_lang self.cur_lang_code_id = self.lang_code_to_id[self._src_lang] self.set_src_lang_special_tokens(self._src_lang) @property def src_lang(self) -> str: return self._src_lang @src_lang.setter def src_lang(self, new_src_lang: str) -> None: self._src_lang = new_src_lang self.set_src_lang_special_tokens(self._src_lang)
[docs] 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 set_lang. An MBART-50 sequence has the following format, where ``X`` represents the sequence: - ``input_ids`` (for encoder) ``[src_lang_code] X [eos]`` - ``labels``: (for decoder) ``[tgt_lang_code] X [eos]`` BOS is never used. 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 + self.suffix_tokens # 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 + self.suffix_tokens
[docs] def prepare_seq2seq_batch( self, src_texts: List[str], src_lang: str = "en_XX", tgt_texts: Optional[List[str]] = None, tgt_lang: str = "ro_RO", **kwargs, ) -> BatchEncoding: self.src_lang = src_lang self.tgt_lang = tgt_lang return super().prepare_seq2seq_batch(src_texts, tgt_texts, **kwargs)
[docs] @contextmanager def as_target_tokenizer(self): """ Temporarily sets the tokenizer for encoding the targets. Useful for tokenizer associated to sequence-to-sequence models that need a slightly different processing for the labels. """ self.set_tgt_lang_special_tokens(self.tgt_lang) yield self.set_src_lang_special_tokens(self.src_lang)
[docs] def set_src_lang_special_tokens(self, src_lang: str) -> None: """Reset the special tokens to the source lang setting. prefix=[src_lang_code] and suffix=[eos].""" self.cur_lang_code_id = self.convert_tokens_to_ids(src_lang) self.prefix_tokens = [self.cur_lang_code_id] self.suffix_tokens = [self.eos_token_id] prefix_tokens_str = self.convert_ids_to_tokens(self.prefix_tokens) suffix_tokens_str = self.convert_ids_to_tokens(self.suffix_tokens) self._tokenizer.post_processor = processors.TemplateProcessing( single=prefix_tokens_str + ["$A"] + suffix_tokens_str, pair=prefix_tokens_str + ["$A", "$B"] + suffix_tokens_str, special_tokens=list(zip(prefix_tokens_str + suffix_tokens_str, self.prefix_tokens + self.suffix_tokens)), )
[docs] def set_tgt_lang_special_tokens(self, tgt_lang: str) -> None: """Reset the special tokens to the target language setting. prefix=[src_lang_code] and suffix=[eos].""" self.cur_lang_code_id = self.convert_tokens_to_ids(tgt_lang) self.prefix_tokens = [self.cur_lang_code_id] self.suffix_tokens = [self.eos_token_id] prefix_tokens_str = self.convert_ids_to_tokens(self.prefix_tokens) suffix_tokens_str = self.convert_ids_to_tokens(self.suffix_tokens) self._tokenizer.post_processor = processors.TemplateProcessing( single=prefix_tokens_str + ["$A"] + suffix_tokens_str, pair=prefix_tokens_str + ["$A", "$B"] + suffix_tokens_str, special_tokens=list(zip(prefix_tokens_str + suffix_tokens_str, self.prefix_tokens + self.suffix_tokens)), )
def _build_translation_inputs(self, raw_inputs, src_lang: Optional[str], tgt_lang: Optional[str], **extra_kwargs): """Used by translation pipeline, to prepare inputs for the generate function""" if src_lang is None or tgt_lang is None: raise ValueError("Translation requires a `src_lang` and a `tgt_lang` for this model") self.src_lang = src_lang inputs = self(raw_inputs, add_special_tokens=True, return_tensors="pt", **extra_kwargs) tgt_lang_id = self.convert_tokens_to_ids(tgt_lang) inputs["forced_bos_token_id"] = tgt_lang_id return inputs
[docs] def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]: if not os.path.isdir(save_directory): logger.error(f"Vocabulary path ({save_directory}) should be a directory") return out_vocab_file = os.path.join( save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["vocab_file"] ) if os.path.abspath(self.vocab_file) != os.path.abspath(out_vocab_file): copyfile(self.vocab_file, out_vocab_file) return (out_vocab_file,)