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# Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
"""Megatron tokenizers."""
from abc import ABC
from abc import abstractmethod
from .bert_tokenization import FullTokenizer as FullBertTokenizer
from .gpt2_tokenization import GPT2Tokenizer
def build_tokenizer(args):
"""Initialize tokenizer."""
if args.rank == 0:
print('> building {} tokenizer ...'.format(args.tokenizer_type),
flush=True)
# Select and instantiate the tokenizer.
if args.tokenizer_type == 'BertWordPieceLowerCase':
assert args.vocab_file is not None
tokenizer = _BertWordPieceTokenizer(vocab_file=args.vocab_file,
lower_case=True,
vocab_extra_ids=args.vocab_extra_ids)
elif args.tokenizer_type == 'BertWordPieceCase':
assert args.vocab_file is not None
tokenizer = _BertWordPieceTokenizer(vocab_file=args.vocab_file,
lower_case=False,
vocab_extra_ids=args.vocab_extra_ids)
elif args.tokenizer_type == 'GPT2BPETokenizer':
assert args.vocab_file is not None
assert args.merge_file is not None
tokenizer = _GPT2BPETokenizer(args.vocab_file, args.merge_file)
elif args.tokenizer_type == 'SentencePieceTokenizer':
assert args.tokenizer_model is not None
tokenizer = _SentencePieceTokenizer(args.tokenizer_model, vocab_extra_ids=args.vocab_extra_ids)
elif args.tokenizer_type == 'GPTSentencePieceTokenizer':
assert args.tokenizer_model is not None
tokenizer = _GPTSentencePieceTokenizer(args.tokenizer_model)
elif args.tokenizer_type == 'NullTokenizer':
assert args.vocab_size is not None
tokenizer = _NullTokenizer(args.vocab_size)
else:
raise NotImplementedError('{} tokenizer is not '
'implemented.'.format(args.tokenizer_type))
# Add vocab size.
args.padded_vocab_size = _vocab_size_with_padding(tokenizer.vocab_size,
args)
return tokenizer
def _vocab_size_with_padding(orig_vocab_size, args):
"""Pad vocab size so it is divisible by model parallel size and
still having GPU friendly size."""
after = orig_vocab_size
multiple = args.make_vocab_size_divisible_by * \
args.tensor_model_parallel_size
while (after % multiple) != 0:
after += 1
if args.rank == 0:
print(' > padded vocab (size: {}) with {} dummy tokens '
'(new size: {})'.format(
orig_vocab_size, after - orig_vocab_size, after), flush=True)
return after
class AbstractTokenizer(ABC):
"""Abstract class for tokenizer."""
def __init__(self, name):
self.name = name
super().__init__()
@property
@abstractmethod
def vocab_size(self):
pass
@property
@abstractmethod
def vocab(self):
"""Dictionary from vocab text token to id token."""
pass
@property
@abstractmethod
def inv_vocab(self):
"""Dictionary from vocab id token to text token."""
pass
@abstractmethod
def tokenize(self, text):
pass
def detokenize(self, token_ids):
raise NotImplementedError('detokenizer is not implemented for {} '
'tokenizer'.format(self.name))
@property
def cls(self):
raise NotImplementedError('CLS is not provided for {} '
'tokenizer'.format(self.name))
@property
def sep(self):
raise NotImplementedError('SEP is not provided for {} '
'tokenizer'.format(self.name))
@property
def pad(self):
raise NotImplementedError('PAD is not provided for {} '
'tokenizer'.format(self.name))
@property
def eod(self):
raise NotImplementedError('EOD is not provided for {} '
'tokenizer'.format(self.name))
@property
def mask(self):
raise NotImplementedError('MASK is not provided for {} '
'tokenizer'.format(self.name))
class _BertWordPieceTokenizer(AbstractTokenizer):
"""Original BERT wordpiece tokenizer."""
def __init__(self, vocab_file, lower_case=True, vocab_extra_ids=0):
if lower_case:
name = 'BERT Lower Case'
else:
name = 'BERT Upper Case'
super().__init__(name)
self.tokenizer = FullBertTokenizer(vocab_file, do_lower_case=lower_case)
self.cls_id = self.tokenizer.vocab['[CLS]']
self.sep_id = self.tokenizer.vocab['[SEP]']
self.pad_id = self.tokenizer.vocab['[PAD]']
self.mask_id = self.tokenizer.vocab['[MASK]']
self._additional_special_tokens = []
# (dsachan) Add BOS and EOS tokens
SPECIAL_TOKENS = {'eos_token': '[EOS]',
'bos_token': '[BOS]'}
self._bos_token = '[BOS]'
self.add_token(self._bos_token)
self._bos_token_id = self.vocab.get(self._bos_token)
self._eos_token = '[EOS]'
self.add_token(self._eos_token)
self._eos_token_id = self.vocab.get(self._eos_token)
# (dsachan) Add additional special tokens
# These can be used as sentinel tokens in T5 model inputs
additional_special_tokens = []
additional_special_tokens.extend(
["<extra_id_{}>".format(i) for i in range(vocab_extra_ids)])
self.add_additional_special_tokens(additional_special_tokens)
def add_token(self, token):
if token not in self.vocab:
self.inv_vocab[self.vocab_size] = token
# self.vocab_size comes from len(vocab)
# and it will increase as we add elements
self.vocab[token] = self.vocab_size
def add_additional_special_tokens(self, tokens_list):
setattr(self, "additional_special_tokens", tokens_list)
for value in tokens_list:
self.add_token(value)
@property
def vocab_size(self):
return self.tokenizer.vocab_size()
@property
def vocab(self):
return self.tokenizer.vocab
@property
def inv_vocab(self):
return self.tokenizer.inv_vocab
def tokenize(self, text):
text_tokens = self.tokenizer.tokenize(text)
return self.tokenizer.convert_tokens_to_ids(text_tokens)
def decode(self, ids):
tokens = self.tokenizer.convert_ids_to_tokens(ids)
return self.tokenizer.convert_tokens_to_string(tokens)
def decode_token_ids(self, token_ids):
tokens = self.tokenizer.convert_ids_to_tokens(token_ids)
exclude_list = ['[PAD]', '[CLS]']
non_pads = [t for t in tokens if t not in exclude_list]
result = ""
for s in non_pads:
if s.startswith("##"):
result += s[2:]
else:
result += " " + s
return result
@property
def cls(self):
return self.cls_id
@property
def sep(self):
return self.sep_id
@property
def pad(self):
return self.pad_id
@property
def mask(self):
return self.mask_id
@property
def bos_token(self):
""" Beginning of sentence token id """
return self._bos_token
@property
def eos_token(self):
""" End of sentence token id """
return self._eos_token
@property
def additional_special_tokens(self):
""" All the additional special tokens you may want to use (list of strings)."""
return self._additional_special_tokens
@property
def bos_token_id(self):
""" Id of the beginning of sentence token in the vocabulary."""
return self._bos_token_id
@property
def eos_token_id(self):
""" Id of the end of sentence token in the vocabulary."""
return self._eos_token_id
@property
def additional_special_tokens_ids(self):
""" Ids of all the additional special tokens in the vocabulary (list of integers)."""
return [self.vocab.get(token) for token in self._additional_special_tokens]
@additional_special_tokens.setter
def additional_special_tokens(self, value):
self._additional_special_tokens = value
class _GPT2BPETokenizer(AbstractTokenizer):
"""Original GPT2 BPE tokenizer."""
def __init__(self, vocab_file, merge_file):
name = 'GPT2 BPE'
super().__init__(name)
self.tokenizer = GPT2Tokenizer(vocab_file, merge_file, errors='replace',
special_tokens=[], max_len=None)
self.eod_id = self.tokenizer.encoder['<|endoftext|>']
@property
def vocab_size(self):
return len(self.tokenizer.encoder)
@property
def vocab(self):
return self.tokenizer.encoder
@property
def inv_vocab(self):
return self.tokenizer.decoder
def tokenize(self, text):
return self.tokenizer.encode(text)
def detokenize(self, token_ids):
return self.tokenizer.decode(token_ids)
@property
def eod(self):
return self.eod_id
class _SentencePieceTokenizer(AbstractTokenizer):
"""SentencePieceTokenizer-Megatron wrapper"""
def __init__(self, model_file, vocab_extra_ids=0):
name = 'SentencePieceTokenizer'
super().__init__(name)
import sentencepiece
self.tokenizer = sentencepiece.SentencePieceProcessor(model_file=model_file)
self._initalize(vocab_extra_ids)
def _populate_vocab(self):
self._vocab = {}
self._inv_vocab = {}
for i in range(len(self.tokenizer)):
t = self.tokenizer.id_to_piece(i)
self._inv_vocab[i] = t
self._vocab[t] = i
def _initalize(self, vocab_extra_ids):
self._populate_vocab()
self._special_tokens = {}
self._inv_special_tokens = {}
self._t5_tokens = []
def _add_special_token(t):
if t not in self._vocab:
next_id = len(self._vocab)
self._vocab[t] = next_id
self._inv_vocab[next_id] = t
self._special_tokens[t] = self._vocab[t]
self._inv_special_tokens[self._vocab[t]] = t
_add_special_token('<CLS>')
self._cls_id = self._vocab['<CLS>']
_add_special_token('<SEP>')
self._sep_id = self._vocab['<SEP>']
_add_special_token('<EOD>')
self._eod_id = self._vocab['<EOD>']
_add_special_token('<MASK>')
self._mask_id = self._vocab['<MASK>']
pad_id = self.tokenizer.pad_id()
try:
pad_token = self.tokenizer.id_to_piece(pad_id)
except IndexError:
pad_token = '<PAD>'
_add_special_token(pad_token)
self._pad_id = self._vocab[pad_token]
bos_id = self.tokenizer.bos_id()
try:
bos_token = self.tokenizer.id_to_piece(bos_id)
except IndexError:
bos_token = '<BOS>'
_add_special_token(bos_token)
self._bos_id = self._vocab[bos_token]
eos_id = self.tokenizer.eos_id()
try:
eos_token = self.tokenizer.id_to_piece(eos_id)
except IndexError:
eos_token = '<EOS>'
_add_special_token(eos_token)
self._eos_id = self._vocab[eos_token]
for i in range(vocab_extra_ids):
t = "<extra_id_{}>".format(i)
_add_special_token(t)
self._t5_tokens += [t]
@property
def vocab_size(self):
return len(self._vocab)
@property
def vocab(self):
return self._vocab
@property
def inv_vocab(self):
return self._inv_vocab
@property
def decoder(self):
return self._inv_vocab
@property
def encoder(self):
return self._vocab
# From:
# https://github.com/NVIDIA/NeMo/blob/c8fa217e811d60d11d014827c7f3845ff6c99ae7/nemo/collections/common/tokenizers/sentencepiece_tokenizer.py#L89
def tokenize(self, text):
ids = []
idx = 0
while 1:
indices = {}
for token in self._special_tokens:
try:
indices[token] = text[idx:].index(token)
except ValueError:
continue
if len(indices) == 0:
break
next_token = min(indices, key=indices.get)
next_idx = idx + indices[next_token]
ids.extend(self.tokenizer.encode_as_ids(text[idx:next_idx]))
ids.append(self._special_tokens[next_token])
idx = next_idx + len(next_token)
ids.extend(self.tokenizer.encode_as_ids(text[idx:]))
return ids
# From:
# https://github.com/NVIDIA/NeMo/blob/c8fa217e811d60d11d014827c7f3845ff6c99ae7/nemo/collections/common/tokenizers/sentencepiece_tokenizer.py#L125
def detokenize(self, ids):
text = ""
last_i = 0
for i, id in enumerate(ids):
if id in self._inv_special_tokens:
text += self.tokenizer.decode_ids(ids[last_i:i]) + " "
text += self._inv_special_tokens[id] + " "
last_i = i + 1
text += self.tokenizer.decode_ids(ids[last_i:])
return text
@property
def cls(self):
return self._cls_id
@property
def sep(self):
return self._sep_id
@property
def pad(self):
return self._pad_id
@property
def bos_token_id(self):
return self._bos_id
@property
def bos(self):
return self._bos_id
@property
def eod(self):
return self._eod_id
@property
def eos_token_id(self):
return self._eos_id
@property
def eos(self):
return self._eos_id
@property
def mask(self):
return self._mask_id
@property
def additional_special_tokens_ids(self):
return [self.vocab[k] for k in self._t5_tokens]
class _GPTSentencePieceTokenizer(_SentencePieceTokenizer):
"""SentencePieceTokenizer-Megatron wrapper"""
def __init__(self, model_file,):
super().__init__(model_file, vocab_extra_ids=0)
def _initalize(self, vocab_extra_ids):
self._populate_vocab()
self._pad_id = self.tokenizer.pad_id()
self._bos_id = self.tokenizer.bos_id()
self._eos_id = self.tokenizer.eos_id()
def tokenize(self, text):
return self.tokenizer.encode_as_ids(text)
def detokenize(self, ids):
return self.tokenizer.decode_ids(ids)
@property
def cls(self):
return -1
@property
def sep(self):
return -1
@property
def mask(self):
return -1
@property
def eod(self):
return self._eos_id
@property
def additional_special_tokens_ids(self):
return None
class _NullTokenizer:
def __init__(self, vocab_size):
vocab_size = int(vocab_size)
self._eos_id = vocab_size
self.vocab_size = vocab_size+1
def tokenize(self, text):
return [int(x) for x in text.split(' ')]
def detokenize(self, ids):
text = [str(x) for x in ids]
return ' '.join(text)
@property
def cls(self):
return -1
@property
def sep(self):
return -1
@property
def mask(self):
return -1
@property
def eod(self):
return self._eos_id
@property
def additional_special_tokens_ids(self):
return None