def train_new_from_iterator(self,
text_iterator,
s_vocab,
new_special_tokens=None,
special_tokens_map=None,
**kw):
tokenizer_json = json.loads(self._tokenizer.to_str())
# Remove added tokens for now (uses IDs of tokens)
added_tokens = tokenizer_json.pop("added_tokens")
# Remove post processor for now (uses IDs of tokens)
post_processor = tokenizer_json.pop("post_processor")
unk = None
# Remove vocab
if tokenizer_json["model"]["type"] == "BPE":
tokenizer_json["model"]["vocab"] = {}
tokenizer_json["model"]["merges"] = []
elif tokenizer_json["model"]["type"] == "Unigram":
if tokenizer_json["model"]["unk_id"] is not None:
unk_id = tokenizer_json["model"]["unk_id"]
unk = tokenizer_json["model"]["vocab"][unk_id][0]
if special_tokens_map is not None and unk in special_tokens_map:
unk = special_tokens_map[unk]
tokenizer_json["model"]["unk_id"] = 0
tokenizer_json["model"]["vocab"] = [[unk, 0.0]]
elif tokenizer_json["model"]["type"] in ["WordLevel", "WordPiece"]:
tokenizer_json["model"]["vocab"] = {}
else:
raise ValueError(
f"This method does not support this type of tokenizer (found {tokenizer_json['model']['type']}) "
"only BPE, Unigram, WordLevel and WordPiece.")
if (special_tokens_map is not None and "unk" in tokenizer_json["model"]
and tokenizer_json["model"]["unk"] in special_tokens_map):
tokenizer_json["model"]["unk"] = special_tokens_map[
tokenizer_json["model"]["unk"]]
tokenizer = TokenizerFast.from_str(json.dumps(tokenizer_json))
# Get the special tokens from the current tokenizer if none are specified.
special_tokens = []
for added_token in added_tokens:
special = added_token.pop("special", None)
_ = added_token.pop("id", None)
if tokenizer_json["model"]["type"] != "Unigram" and not special:
continue
if special_tokens_map is not None and added_token[
"content"] in special_tokens_map:
added_token["content"] = special_tokens_map[
added_token["content"]]
special_tokens.append(AddedToken(**added_token))
if new_special_tokens is not None:
special_tokens.extend(new_special_tokens)
# Trainer needs to know the end of word / continuing subword thingies in BPE
if (tokenizer_json["model"]["type"] == "BPE"
and "continuing_subword_prefix" not in kw
and tokenizer_json["model"]["continuing_subword_prefix"]
is not None):
kw["continuing_subword_prefix"] = tokenizer_json["model"][
"continuing_subword_prefix"]
if (tokenizer_json["model"]["type"] == "BPE"
and "end_of_word_suffix" not in kw
and tokenizer_json["model"]["end_of_word_suffix"] is not None):
kw["end_of_word_suffix"] = tokenizer_json["model"][
"end_of_word_suffix"]
if tokenizer_json["model"]["type"] == "Unigram" and unk is not None:
kw["unk"] = unk
trainer_class = MODEL_TO_TRAINER_MAPPING[tokenizer_json["model"]
["type"]]
trainer = trainer_class(s_vocab=s_vocab,
special_tokens=special_tokens,
**kw)
tokenizer.train_from_iterator(text_iterator, trainer=trainer)
if post_processor is not None:
trained_tokenizer_json = json.loads(tokenizer.to_str())
# Almost done, we just have to adjust the token IDs in the post processor
if "special_tokens" in post_processor:
for key in post_processor["special_tokens"]:
tokens = post_processor["special_tokens"][key]["tokens"]
if special_tokens_map is not None:
tokens = [
special_tokens_map.get(token, token)
for token in tokens
]
post_processor["special_tokens"][key]["tokens"] = tokens
post_processor["special_tokens"][key]["ids"] = [
tokenizer.token_to_id(token) for token in tokens
]
for special_token in ["cls", "sep"]:
if special_token in post_processor:
token, _ = post_processor[special_token]
if special_tokens_map is not None and token in special_tokens_map:
token = special_tokens_map[token]
token_id = tokenizer.token_to_id(token)
post_processor[special_token] = [token, token_id]
trained_tokenizer_json["post_processor"] = post_processor
tokenizer = TokenizerFast.from_str(
json.dumps(trained_tokenizer_json))
kw = self.init_kw.copy()
# Map pad/cls/mask token at the Transformers level
special_tokens_list = SpecialTokensMixin.SPECIAL_TOKENS_ATTRIBUTES.copy(
)
special_tokens_list.remove("additional_special_tokens")
for token in special_tokens_list:
# Get the private one to avoid unnecessary warnings.
if getattr(self, f"_{token}") is not None:
special_token = getattr(self, token)
if special_tokens_map is not None and special_token in special_tokens_map:
special_token = special_tokens_map[special_token]
special_token_full = getattr(self, f"_{token}")
if isinstance(special_token_full, AddedToken):
# Create an added token with the same parameters except the content
kw[token] = AddedToken(
special_token,
single_word=special_token_full.single_word,
lstrip=special_token_full.lstrip,
rstrip=special_token_full.rstrip,
normalized=special_token_full.normalized,
)
else:
kw[token] = special_token
additional_special_tokens = self.additional_special_tokens
if new_special_tokens is not None:
additional_special_tokens.extend(new_special_tokens)
if len(additional_special_tokens) > 0:
kw["additional_special_tokens"] = additional_special_tokens
return self.__class__(tokenizer_object=tokenizer, **kw)
def deserialize(cls, s: str) -> 'SentencePieceBPETokenizer':
tokenizer = cls()
tokenizer.tokenizer = Tokenizer.from_str(s)
return tokenizer
def train_new_from_iterator(
self,
text_iterator,
vocab_size,
length=None,
new_special_tokens=None,
special_tokens_map=None,
**kwargs,
):
"""
Trains a tokenizer on a new corpus with the same defaults (in terms of special tokens or tokenization pipeline)
as the current one.
Args:
text_iterator (generator of `List[str]`):
The training corpus. Should be a generator of batches of texts, for instance a list of lists of texts
if you have everything in memory.
vocab_size (`int`):
The size of the vocabulary you want for your tokenizer.
length (`int`, *optional*):
The total number of sequences in the iterator. This is used to provide meaningful progress tracking
new_special_tokens (list of `str` or `AddedToken`, *optional*):
A list of new special tokens to add to the tokenizer you are training.
special_tokens_map (`Dict[str, str]`, *optional*):
If you want to rename some of the special tokens this tokenizer uses, pass along a mapping old special
token name to new special token name in this argument.
kwargs:
Additional keyword arguments passed along to the trainer from the 🤗 Tokenizers library.
Returns:
[`PreTrainedTokenizerFast`]: A new tokenizer of the same type as the original one, trained on
`text_iterator`.
"""
tokenizer_json = json.loads(self._tokenizer.to_str())
# Remove added tokens for now (uses IDs of tokens)
added_tokens = tokenizer_json.pop("added_tokens")
# Remove post processor for now (uses IDs of tokens)
post_processor = tokenizer_json.pop("post_processor")
unk_token = None
# Remove vocab
if tokenizer_json["model"]["type"] == "BPE":
tokenizer_json["model"]["vocab"] = {}
tokenizer_json["model"]["merges"] = []
elif tokenizer_json["model"]["type"] == "Unigram":
if tokenizer_json["model"]["unk_id"] is not None:
unk_id = tokenizer_json["model"]["unk_id"]
unk_token = tokenizer_json["model"]["vocab"][unk_id][0]
if special_tokens_map is not None and unk_token in special_tokens_map:
unk_token = special_tokens_map[unk_token]
tokenizer_json["model"]["unk_id"] = 0
tokenizer_json["model"]["vocab"] = [[unk_token, 0.0]]
elif tokenizer_json["model"]["type"] in ["WordLevel", "WordPiece"]:
tokenizer_json["model"]["vocab"] = {}
else:
raise ValueError(
f"This method does not support this type of tokenizer (found {tokenizer_json['model']['type']}) "
"only BPE, Unigram, WordLevel and WordPiece.")
if (special_tokens_map is not None
and "unk_token" in tokenizer_json["model"] and
tokenizer_json["model"]["unk_token"] in special_tokens_map):
tokenizer_json["model"]["unk_token"] = special_tokens_map[
tokenizer_json["model"]["unk_token"]]
tokenizer = TokenizerFast.from_str(json.dumps(tokenizer_json))
# Get the special tokens from the current tokenizer if none are specified.
special_tokens = []
for added_token in added_tokens:
special = added_token.pop("special", None)
_ = added_token.pop("id", None)
if tokenizer_json["model"]["type"] != "Unigram" and not special:
continue
if special_tokens_map is not None and added_token[
"content"] in special_tokens_map:
added_token["content"] = special_tokens_map[
added_token["content"]]
special_tokens.append(AddedToken(**added_token))
if new_special_tokens is not None:
special_tokens.extend(new_special_tokens)
# Trainer needs to know the end of word / continuing subword thingies in BPE
if (tokenizer_json["model"]["type"] == "BPE"
and "continuing_subword_prefix" not in kwargs
and tokenizer_json["model"]["continuing_subword_prefix"]
is not None):
kwargs["continuing_subword_prefix"] = tokenizer_json["model"][
"continuing_subword_prefix"]
if (tokenizer_json["model"]["type"] == "BPE"
and "end_of_word_suffix" not in kwargs
and tokenizer_json["model"]["end_of_word_suffix"] is not None):
kwargs["end_of_word_suffix"] = tokenizer_json["model"][
"end_of_word_suffix"]
if tokenizer_json["model"][
"type"] == "Unigram" and unk_token is not None:
kwargs["unk_token"] = unk_token
trainer_class = MODEL_TO_TRAINER_MAPPING[tokenizer_json["model"]
["type"]]
trainer = trainer_class(vocab_size=vocab_size,
special_tokens=special_tokens,
**kwargs)
tokenizer.train_from_iterator(text_iterator,
length=length,
trainer=trainer)
if post_processor is not None:
trained_tokenizer_json = json.loads(tokenizer.to_str())
# Almost done, we just have to adjust the token IDs in the post processor
if "special_tokens" in post_processor:
for key in post_processor["special_tokens"]:
tokens = post_processor["special_tokens"][key]["tokens"]
if special_tokens_map is not None:
tokens = [
special_tokens_map.get(token, token)
for token in tokens
]
post_processor["special_tokens"][key]["tokens"] = tokens
post_processor["special_tokens"][key]["ids"] = [
tokenizer.token_to_id(token) for token in tokens
]
for special_token in ["cls", "sep"]:
if special_token in post_processor:
token, _ = post_processor[special_token]
if special_tokens_map is not None and token in special_tokens_map:
token = special_tokens_map[token]
token_id = tokenizer.token_to_id(token)
post_processor[special_token] = [token, token_id]
trained_tokenizer_json["post_processor"] = post_processor
tokenizer = TokenizerFast.from_str(
json.dumps(trained_tokenizer_json))
kwargs = self.init_kwargs.copy()
# Map pad/cls/mask token at the Transformers level
special_tokens_list = SpecialTokensMixin.SPECIAL_TOKENS_ATTRIBUTES.copy(
)
special_tokens_list.remove("additional_special_tokens")
for token in special_tokens_list:
# Get the private one to avoid unnecessary warnings.
if getattr(self, f"_{token}") is not None:
special_token = getattr(self, token)
if special_tokens_map is not None and special_token in special_tokens_map:
special_token = special_tokens_map[special_token]
special_token_full = getattr(self, f"_{token}")
if isinstance(special_token_full, AddedToken):
# Create an added token with the same parameters except the content
kwargs[token] = AddedToken(
special_token,
single_word=special_token_full.single_word,
lstrip=special_token_full.lstrip,
rstrip=special_token_full.rstrip,
normalized=special_token_full.normalized,
)
else:
kwargs[token] = special_token
additional_special_tokens = self.additional_special_tokens
if new_special_tokens is not None:
additional_special_tokens.extend(new_special_tokens)
if len(additional_special_tokens) > 0:
kwargs["additional_special_tokens"] = additional_special_tokens
return self.__class__(tokenizer_object=tokenizer, **kwargs)
def add_unk_id(self):
tokenizer_json = json.loads(self._tokenizer.to_str())
tokenizer_json["model"]["unk_id"] = self.special_tokens["unk"]["id"]
self._tokenizer = Tokenizer.from_str(json.dumps(tokenizer_json))
