def mask_tokens(inputs, bert_tokenizer: BertTokenizer,
jp_tokenizer: JumanTokenizer, args):
""" Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. """
labels = inputs.clone()
# パディング部分(-1)も除外対象に設定
# -1部分を持ったパディングマスクを作成
padding_mask = labels.clone()
# パディングを認識可能な0([UNK])に戻す
inputs[padding_mask == -1] = 0
# 予測に使う部分を確率決定(True = 1.0)
# We sample a few tokens in each sequence for masked-LM training (with probability args.mlm_probability defaults to 0.15 in Bert/RoBERTa)
probability_matrix = torch.full(labels.shape, args.mlm_probability)
special_tokens_mask = [
bert_tokenizer.get_special_tokens_mask(val,
already_has_special_tokens=True)
for val in labels.tolist()
]
probability_matrix.masked_fill_(torch.tensor(special_tokens_mask,
dtype=torch.bool).byte(),
value=0.0)
masked_indices = torch.bernoulli(probability_matrix)
labels[(masked_indices !=
1.0)] = -1 # We only compute loss on masked tokens
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = torch.bernoulli(torch.full(labels.shape, 0.8))
inputs[(indices_replaced == 1.0)
& (labels == -1)] = bert_tokenizer.convert_tokens_to_ids(
bert_tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
indices_random = torch.bernoulli(torch.full(labels.shape, 0.5))
random_words = torch.randint(len(bert_tokenizer),
labels.shape,
dtype=torch.long)
inputs[(indices_random == 1.0) & (indices_replaced == 1.0) &
(labels == -1)] = random_words[(indices_random == 1.0)
& (indices_replaced == 1.0) &
(labels == -1)]
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels
def mask_token(inputs: torch.Tensor, tokenizer: BertTokenizer,
args) -> Tuple[torch.Tensor, torch.Tensor]:
if tokenizer.mask_token is None:
raise ValueError(
'This tokenizer does not have a mask token which is necessary for masked language model. Remove the --mlm flag if you want to use this tokenizer.'
)
labels = inputs.clone()
# We sample a few tokens in each sequence for masked-LM training (with probability args.mlm_probability defaults to 0.15 in Bert/RoBERTa)
probability_matrix = torch.full(labels.shape, args.mlm_probability)
# filter the exist special token which will not be masked anymore.
special_tokens_mask = [
tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True)
for val in labels.tolist()
]
probability_matrix.masked_fill_(torch.tensor(special_tokens_mask,
dtype=torch.bool),
value=0.0)
# filter the exist pad token which will not be masked anymore
if tokenizer.pad_token is not None:
padding_mask = labels.eq(tokenizer.pad_token_id)
probability_matrix.masked_fill_(padding_mask, value=0.0)
# get out the possible masked position with 1.0 which means 15% of all pure tokens will be picked out for relevant masking.
masked_indices = torch.bernoulli(probability_matrix).bool()
# we only need the masked position to compute loss while the other token ids are set to be -100
labels[~masked_indices] = -100
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = torch.bernoulli(torch.full(labels.shape,
0.8)).bool() & masked_indices
inputs[indices_replaced] = tokenizer.convert_tokens_to_ids(
tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
indices_random = torch.bernoulli(torch.full(
labels.shape, 0.5)).bool() & masked_indices & ~indices_replaced
random_words = torch.randint(len(tokenizer),
labels.shape,
dtype=torch.long)
inputs[indices_random] = random_words[indices_random]
# The rest of the time(10%) we keep the masked input tokens unchanged
return inputs, labels
def mask_tokens(inputs: torch.Tensor, tokenizer: BertTokenizer,
args) -> Tuple[torch.Tensor, torch.Tensor]:
""" Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. """
labels = inputs.clone()
# We sample a few tokens in each sequence for masked-LM training (with probability args.mlm_probability defaults to 0.15 in Bert/RoBERTa)
probability_matrix = torch.full(labels.shape, args.mlm_probability)
special_tokens_mask = [
tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True)
for val in labels.tolist()
]
probability_matrix.masked_fill_(torch.tensor(special_tokens_mask,
dtype=torch.bool),
value=0.0)
if tokenizer._pad_token is not None:
padding_mask = labels.eq(tokenizer.pad_token_id)
probability_matrix.masked_fill_(padding_mask, value=0.0)
masked_indices = torch.bernoulli(probability_matrix).bool()
labels[~masked_indices] = -100 # We only compute loss on masked tokens
inputs[masked_indices] = tokenizer.convert_tokens_to_ids(
tokenizer.mask_token)
return inputs, labels
def mask_tokens(inputs: torch.Tensor, tokenizer: BertTokenizer,
args) -> Tuple[torch.Tensor, torch.Tensor]:
""" Prepare masked tokens inputs/labels for masked language modeling: 80% MASK, 10% random, 10% original. """
labels = inputs.clone()
# We sample a few tokens in each sequence for masked-LM training (with probability args.mlm_probability defaults to 0.15 in Bert/RoBERTa)
probability_matrix = torch.full(labels.shape, args.mlm_probability)
special_tokens_mask = [
tokenizer.get_special_tokens_mask(val, already_has_special_tokens=True)
for val in labels.tolist()
]
probability_matrix.masked_fill_(torch.tensor(special_tokens_mask,
dtype=torch.bool),
value=0.0)
if tokenizer._pad_token is not None:
padding_mask = labels.eq(tokenizer.pad_token_id)
probability_matrix.masked_fill_(padding_mask, value=0.0)
masked_indices = torch.bernoulli(probability_matrix).bool()
labels[~masked_indices] = -100 # We only compute loss on masked tokens
# TODO replace all tokens-to-be-changed with [MASK] (prob 80% -> 100%)
# 80% of the time, we replace masked input tokens with tokenizer.mask_token ([MASK])
indices_replaced = torch.bernoulli(torch.full(labels.shape,
0.8)).bool() & masked_indices
inputs[indices_replaced] = tokenizer.convert_tokens_to_ids(
tokenizer.mask_token)
# 10% of the time, we replace masked input tokens with random word
indices_random = (torch.bernoulli(torch.full(labels.shape, 0.5)).bool()
& masked_indices & ~indices_replaced)
random_words = torch.randint(len(tokenizer),
labels.shape,
dtype=torch.long)
inputs[indices_random] = random_words[indices_random]
# The rest of the time (10% of the time) we keep the masked input tokens unchanged
return inputs, labels
tokenizer.eos_token_id
tokenizer.all_special_ids
tokenizer.special_tokens_map
tokenizer.additional_special_tokens
y = "<BOS> I like embeddings <EOS> [SEP] i like tea"
z = tokenizer.encode(y)
tokenizer.convert_ids_to_tokens(z)
tokenizer.convert_tokens_to_string(tokenizer.convert_ids_to_tokens(z))
tokenizer.encode("embeddings embedding")
tokenizer.encode("i like tea")
tokenizer.encode("i like tea")
tokenizer.decode(tokenizer.encode("embeddings embedding"))
tokenizer.get_special_tokens_mask([100, 101, 102], [1, 2, 3])
tokenizer.get_special_tokens_mask([100, 101, 102, 1, 2, 3])
tokenizer("s")
from transformers import BertTokenizerFast
t1 = BertTokenizerFast.from_pretrained("bert-base-uncased",
bos_token="<BOS>",
eos_token="<EOS>")
t1.tokenize("<BOS> I like embeddings <EOS> [SEP] i like tea")
t1.special_tokens_map
y = t1.encode("<BOS> I like embeddings <EOS> [SEP] i like tea")
t1.create_token_type_ids_from_sequences(y)
t1("abd")
t1.covert_ids_to_tokens(y)