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60 lines
1.9 KiB
Python
60 lines
1.9 KiB
Python
# Copyright (c) Meta Platforms, Inc. and affiliates.
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import logging
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import os
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try:
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from sentencepiece import SentencePieceProcessor
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has_sp = True
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except ImportError:
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has_sp = False
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from bytelatent.tokenizers.abstract_tokenizer import Tokenizer
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logger = logging.getLogger(__name__)
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class SentencePieceTokenizer(Tokenizer):
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def __init__(
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self, model_path: str, add_bos: bool = True, add_eos: bool = True
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) -> None:
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assert os.path.isfile(model_path), model_path
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self.sp_model = SentencePieceProcessor(model_file=model_path)
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logger.info(f"Reloaded SentencePiece model from {model_path}")
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# BOS / EOS token IDs
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self.n_words: int = self.sp_model.vocab_size()
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self.bos_id: int = self.sp_model.bos_id()
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self.eos_id: int = self.sp_model.eos_id()
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self.pad_id: int = self.sp_model.pad_id()
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self.add_bos = add_bos
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self.add_eos = add_eos
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logger.info(
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f"#words: {self.n_words} - BOS ID: {self.bos_id} - EOS ID: {self.eos_id}"
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)
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assert self.sp_model.vocab_size() == self.sp_model.get_piece_size()
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def encode(self, s: str, add_bos: bool | None = None, add_eos: bool | None = None):
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if add_bos is None:
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add_bos = self.add_bos
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if add_eos is None:
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add_eos = self.add_eos
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assert type(s) is str
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tokens = (
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[self.bos_id] * add_bos + self.sp_model.encode(s) + [self.eos_id] * add_eos
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)
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return tokens
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def decode(self, tokens: list[int]):
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return self.sp_model.decode(tokens)
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def get_token_offsets(
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self, text: str, tokens: list[int] | None = None
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) -> tuple[list[str], list[int]]:
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pieces = self.sp_model.encode_as_immutable_proto(text).pieces
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substrs = [p.surface for p in pieces]
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offsets = [p.begin for p in pieces]
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return substrs, offsets
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