338 lines
14 KiB
Python
338 lines
14 KiB
Python
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# coding=utf-8
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# Copyright 2020 The Facebook AI Research Team Authors and The HuggingFace Inc. team.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import os
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from shutil import copyfile
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from typing import Any, Dict, List, Optional, Tuple
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import sentencepiece as spm
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from ...tokenization_utils import AddedToken, BatchEncoding, PreTrainedTokenizer
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from ...utils import logging
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logger = logging.get_logger(__name__)
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SPIECE_UNDERLINE = "▁"
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VOCAB_FILES_NAMES = {"vocab_file": "sentencepiece.bpe.model"}
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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"] # fmt: skip
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class MBartTokenizer(PreTrainedTokenizer):
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"""
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Construct an MBART tokenizer.
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Adapted from [`RobertaTokenizer`] and [`XLNetTokenizer`]. Based on
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[SentencePiece](https://github.com/google/sentencepiece).
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The tokenization method is `<tokens> <eos> <language code>` for source language documents, and `<language code>
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<tokens> <eos>` for target language documents.
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Examples:
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```python
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>>> from transformers import MBartTokenizer
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>>> tokenizer = MBartTokenizer.from_pretrained("facebook/mbart-large-en-ro", src_lang="en_XX", tgt_lang="ro_RO")
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>>> example_english_phrase = " UN Chief Says There Is No Military Solution in Syria"
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>>> expected_translation_romanian = "Şeful ONU declară că nu există o soluţie militară în Siria"
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>>> inputs = tokenizer(example_english_phrase, text_target=expected_translation_romanian, return_tensors="pt")
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```"""
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vocab_files_names = VOCAB_FILES_NAMES
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model_input_names = ["input_ids", "attention_mask"]
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prefix_tokens: List[int] = []
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suffix_tokens: List[int] = []
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def __init__(
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self,
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vocab_file,
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bos_token="<s>",
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eos_token="</s>",
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sep_token="</s>",
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cls_token="<s>",
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unk_token="<unk>",
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pad_token="<pad>",
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mask_token="<mask>",
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tokenizer_file=None,
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src_lang=None,
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tgt_lang=None,
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sp_model_kwargs: Optional[Dict[str, Any]] = None,
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additional_special_tokens=None,
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**kwargs,
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):
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# Mask token behave like a normal word, i.e. include the space before it
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mask_token = (
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AddedToken(mask_token, lstrip=True, normalized=False) if isinstance(mask_token, str) else mask_token
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)
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self.sp_model_kwargs = {} if sp_model_kwargs is None else sp_model_kwargs
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self.sp_model = spm.SentencePieceProcessor(**self.sp_model_kwargs)
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self.sp_model.Load(str(vocab_file))
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self.vocab_file = vocab_file
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# Original fairseq vocab and spm vocab must be "aligned":
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# Vocab | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
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# -------- | ------- | ------- | ------ | ------- | --- | --- | --- | ----- | ----- | ----
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# fairseq | '<s>' | '<pad>' | '</s>' | '<unk>' | ',' | '.' | '▁' | 's' | '▁de' | '-'
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# spm | '<unk>' | '<s>' | '</s>' | ',' | '.' | '▁' | 's' | '▁de' | '-' | '▁a'
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# Mimic fairseq token-to-id alignment for the first 4 token
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self.fairseq_tokens_to_ids = {"<s>": 0, "<pad>": 1, "</s>": 2, "<unk>": 3}
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# The first "real" token "," has position 4 in the original fairseq vocab and position 3 in the spm vocab
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self.fairseq_offset = 1
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self.sp_model_size = len(self.sp_model)
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self.lang_code_to_id = {
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code: self.sp_model_size + i + self.fairseq_offset for i, code in enumerate(FAIRSEQ_LANGUAGE_CODES)
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}
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self.id_to_lang_code = {v: k for k, v in self.lang_code_to_id.items()}
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self.fairseq_tokens_to_ids["<mask>"] = len(self.sp_model) + len(self.lang_code_to_id) + self.fairseq_offset
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self.fairseq_tokens_to_ids.update(self.lang_code_to_id)
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self.fairseq_ids_to_tokens = {v: k for k, v in self.fairseq_tokens_to_ids.items()}
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_additional_special_tokens = list(self.lang_code_to_id.keys())
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if additional_special_tokens is not None:
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# Only add those special tokens if they are not already there.
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_additional_special_tokens.extend(
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[t for t in additional_special_tokens if t not in _additional_special_tokens]
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)
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super().__init__(
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bos_token=bos_token,
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eos_token=eos_token,
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unk_token=unk_token,
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sep_token=sep_token,
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cls_token=cls_token,
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pad_token=pad_token,
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mask_token=mask_token,
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tokenizer_file=None,
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src_lang=src_lang,
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tgt_lang=tgt_lang,
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additional_special_tokens=_additional_special_tokens,
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sp_model_kwargs=self.sp_model_kwargs,
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**kwargs,
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)
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self._src_lang = src_lang if src_lang is not None else "en_XX"
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self.cur_lang_code_id = self.lang_code_to_id[self._src_lang]
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self.tgt_lang = tgt_lang
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self.set_src_lang_special_tokens(self._src_lang)
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def __getstate__(self):
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state = self.__dict__.copy()
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state["sp_model"] = None
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state["sp_model_proto"] = self.sp_model.serialized_model_proto()
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return state
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def __setstate__(self, d):
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self.__dict__ = d
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# for backward compatibility
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if not hasattr(self, "sp_model_kwargs"):
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self.sp_model_kwargs = {}
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self.sp_model = spm.SentencePieceProcessor(**self.sp_model_kwargs)
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self.sp_model.LoadFromSerializedProto(self.sp_model_proto)
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@property
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def vocab_size(self):
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return len(self.sp_model) + len(self.lang_code_to_id) + self.fairseq_offset + 1 # Plus 1 for the mask token
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@property
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def src_lang(self) -> str:
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return self._src_lang
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@src_lang.setter
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def src_lang(self, new_src_lang: str) -> None:
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self._src_lang = new_src_lang
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self.set_src_lang_special_tokens(self._src_lang)
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def get_special_tokens_mask(
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self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None, already_has_special_tokens: bool = False
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) -> List[int]:
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"""
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Retrieve sequence ids from a token list that has no special tokens added. This method is called when adding
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special tokens using the tokenizer `prepare_for_model` method.
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Args:
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token_ids_0 (`List[int]`):
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List of IDs.
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token_ids_1 (`List[int]`, *optional*):
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Optional second list of IDs for sequence pairs.
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already_has_special_tokens (`bool`, *optional*, defaults to `False`):
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Whether or not the token list is already formatted with special tokens for the model.
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Returns:
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`List[int]`: A list of integers in the range [0, 1]: 1 for a special token, 0 for a sequence token.
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"""
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if already_has_special_tokens:
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return super().get_special_tokens_mask(
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token_ids_0=token_ids_0, token_ids_1=token_ids_1, already_has_special_tokens=True
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)
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prefix_ones = [1] * len(self.prefix_tokens)
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suffix_ones = [1] * len(self.suffix_tokens)
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if token_ids_1 is None:
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return prefix_ones + ([0] * len(token_ids_0)) + suffix_ones
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return prefix_ones + ([0] * len(token_ids_0)) + ([0] * len(token_ids_1)) + suffix_ones
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def build_inputs_with_special_tokens(
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self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
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) -> List[int]:
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"""
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Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating and
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adding special tokens. An MBART sequence has the following format, where `X` represents the sequence:
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- `input_ids` (for encoder) `X [eos, src_lang_code]`
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- `decoder_input_ids`: (for decoder) `X [eos, tgt_lang_code]`
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BOS is never used. Pairs of sequences are not the expected use case, but they will be handled without a
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separator.
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Args:
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token_ids_0 (`List[int]`):
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List of IDs to which the special tokens will be added.
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token_ids_1 (`List[int]`, *optional*):
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Optional second list of IDs for sequence pairs.
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Returns:
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`List[int]`: List of [input IDs](../glossary#input-ids) with the appropriate special tokens.
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"""
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if token_ids_1 is None:
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return self.prefix_tokens + token_ids_0 + self.suffix_tokens
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# We don't expect to process pairs, but leave the pair logic for API consistency
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return self.prefix_tokens + token_ids_0 + token_ids_1 + self.suffix_tokens
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def create_token_type_ids_from_sequences(
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self, token_ids_0: List[int], token_ids_1: Optional[List[int]] = None
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) -> List[int]:
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"""
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Create a mask from the two sequences passed to be used in a sequence-pair classification task. mBART does not
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make use of token type ids, therefore a list of zeros is returned.
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Args:
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token_ids_0 (`List[int]`):
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List of IDs.
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token_ids_1 (`List[int]`, *optional*):
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Optional second list of IDs for sequence pairs.
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Returns:
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`List[int]`: List of zeros.
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"""
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sep = [self.sep_token_id]
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cls = [self.cls_token_id]
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if token_ids_1 is None:
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return len(cls + token_ids_0 + sep) * [0]
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return len(cls + token_ids_0 + sep + sep + token_ids_1 + sep) * [0]
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def _build_translation_inputs(
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self, raw_inputs, return_tensors: str, src_lang: Optional[str], tgt_lang: Optional[str], **extra_kwargs
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):
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"""Used by translation pipeline, to prepare inputs for the generate function"""
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if src_lang is None or tgt_lang is None:
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raise ValueError("Translation requires a `src_lang` and a `tgt_lang` for this model")
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self.src_lang = src_lang
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inputs = self(raw_inputs, add_special_tokens=True, return_tensors=return_tensors, **extra_kwargs)
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tgt_lang_id = self.convert_tokens_to_ids(tgt_lang)
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inputs["forced_bos_token_id"] = tgt_lang_id
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return inputs
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def get_vocab(self):
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vocab = {self.convert_ids_to_tokens(i): i for i in range(self.vocab_size)}
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vocab.update(self.added_tokens_encoder)
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return vocab
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def _tokenize(self, text: str) -> List[str]:
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return self.sp_model.encode(text, out_type=str)
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def _convert_token_to_id(self, token):
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"""Converts a token (str) in an id using the vocab."""
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if token in self.fairseq_tokens_to_ids:
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return self.fairseq_tokens_to_ids[token]
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spm_id = self.sp_model.PieceToId(token)
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# Need to return unknown token if the SP model returned 0
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return spm_id + self.fairseq_offset if spm_id else self.unk_token_id
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def _convert_id_to_token(self, index):
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"""Converts an index (integer) in a token (str) using the vocab."""
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if index in self.fairseq_ids_to_tokens:
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return self.fairseq_ids_to_tokens[index]
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return self.sp_model.IdToPiece(index - self.fairseq_offset)
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def convert_tokens_to_string(self, tokens):
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"""Converts a sequence of tokens (strings for sub-words) in a single string."""
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out_string = "".join(tokens).replace(SPIECE_UNDERLINE, " ").strip()
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return out_string
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def save_vocabulary(self, save_directory: str, filename_prefix: Optional[str] = None) -> Tuple[str]:
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if not os.path.isdir(save_directory):
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logger.error(f"Vocabulary path ({save_directory}) should be a directory")
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return
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out_vocab_file = os.path.join(
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save_directory, (filename_prefix + "-" if filename_prefix else "") + VOCAB_FILES_NAMES["vocab_file"]
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)
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if os.path.abspath(self.vocab_file) != os.path.abspath(out_vocab_file) and os.path.isfile(self.vocab_file):
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copyfile(self.vocab_file, out_vocab_file)
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elif not os.path.isfile(self.vocab_file):
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with open(out_vocab_file, "wb") as fi:
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content_spiece_model = self.sp_model.serialized_model_proto()
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fi.write(content_spiece_model)
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return (out_vocab_file,)
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def prepare_seq2seq_batch(
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self,
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src_texts: List[str],
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src_lang: str = "en_XX",
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tgt_texts: Optional[List[str]] = None,
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tgt_lang: str = "ro_RO",
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**kwargs,
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) -> BatchEncoding:
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self.src_lang = src_lang
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self.tgt_lang = tgt_lang
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return super().prepare_seq2seq_batch(src_texts, tgt_texts, **kwargs)
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def _switch_to_input_mode(self):
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return self.set_src_lang_special_tokens(self.src_lang)
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def _switch_to_target_mode(self):
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return self.set_tgt_lang_special_tokens(self.tgt_lang)
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def set_src_lang_special_tokens(self, src_lang) -> None:
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"""Reset the special tokens to the source lang setting. No prefix and suffix=[eos, src_lang_code]."""
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self.cur_lang_code = self.lang_code_to_id[src_lang]
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self.prefix_tokens = []
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self.suffix_tokens = [self.eos_token_id, self.cur_lang_code]
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def set_tgt_lang_special_tokens(self, lang: str) -> None:
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"""Reset the special tokens to the target language setting. No prefix and suffix=[eos, tgt_lang_code]."""
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self.cur_lang_code = self.lang_code_to_id[lang]
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self.prefix_tokens = []
|
||
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self.suffix_tokens = [self.eos_token_id, self.cur_lang_code]
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