def samples_to_features_ner(
sample,
tasks,
max_seq_len,
tokenizer,
non_initial_token="X",
**kwargs
):
"""
Generates a dictionary of features for a given input sample that is to be consumed by an NER model.
:param sample: Sample object that contains human readable text and label fields from a single NER data sample
:type sample: Sample
:param tasks: A dictionary where the keys are the names of the tasks and the values are the details of the task (e.g. label_list, metric, tensor name)
:type tasks: dict
:param max_seq_len: Sequences are truncated after this many tokens
:type max_seq_len: int
:param tokenizer: A tokenizer object that can turn string sentences into a list of tokens
:param non_initial_token: Token that is inserted into the label sequence in positions where there is a
non-word-initial token. This is done since the default NER performs prediction
only on word initial tokens
:return: A list with one dictionary containing the keys "input_ids", "padding_mask", "segment_ids", "initial_mask"
(also "label_ids" if not in inference mode). The values are lists containing those features.
:rtype: list
"""
tokens = sample.tokenized["tokens"]
if tokenizer.is_fast:
text = sample.clear_text["text"]
# Here, we tokenize the sample for the second time to get all relevant ids
# This should change once we git rid of FARM's tokenize_with_metadata()
inputs = tokenizer(text,
return_token_type_ids=True,
truncation=True,
truncation_strategy="longest_first",
max_length=max_seq_len,
return_special_tokens_mask=True)
if (len(inputs["input_ids"]) - inputs["special_tokens_mask"].count(1)) != len(sample.tokenized["tokens"]):
logger.error(f"FastTokenizer encoded sample {sample.clear_text['text']} to "
f"{len(inputs['input_ids']) - inputs['special_tokens_mask'].count(1)} tokens, which differs "
f"from number of tokens produced in tokenize_with_metadata().\n"
f"Further processing is likely to be wrong!")
else:
inputs = tokenizer.encode_plus(text=tokens,
text_pair=None,
add_special_tokens=True,
truncation=False,
return_special_tokens_mask=True,
return_token_type_ids=True,
is_pretokenized=False
)
input_ids, segment_ids, special_tokens_mask = inputs["input_ids"], inputs["token_type_ids"], inputs["special_tokens_mask"]
# We construct a mask to identify the first token of a word. We will later only use them for predicting entities.
# Special tokens don't count as initial tokens => we add 0 at the positions of special tokens
# For BERT we add a 0 in the start and end (for CLS and SEP)
initial_mask = [int(x) for x in sample.tokenized["start_of_word"]]
initial_mask = insert_at_special_tokens_pos(initial_mask, special_tokens_mask, insert_element=0)
assert len(initial_mask) == len(input_ids)
for task_name, task in tasks.items():
try:
label_list = task["label_list"]
label_name = task["label_name"]
label_tensor_name = task["label_tensor_name"]
labels_word = sample.clear_text[label_name]
labels_token = expand_labels(labels_word, initial_mask, non_initial_token)
# labels_token = add_cls_sep(labels_token, cls_token, sep_token)
label_ids = [label_list.index(lt) for lt in labels_token]
except ValueError:
label_ids = None
problematic_labels = set(labels_token).difference(set(label_list))
logger.warning(f"[Task: {task_name}] Could not convert labels to ids via label_list!"
f"\nWe found a problem with labels {str(problematic_labels)}")
except KeyError:
# For inference mode we don't expect labels
label_ids = None
logger.warning(f"[Task: {task_name}] Could not convert labels to ids via label_list!"
"\nIf your are running in *inference* mode: Don't worry!"
"\nIf you are running in *training* mode: Verify you are supplying a proper label list to your processor and check that labels in input data are correct.")
# This mask has 1 for real tokens and 0 for padding tokens. Only real
# tokens are attended to.
padding_mask = [1] * len(input_ids)
# Padding up to the sequence length.
# Normal case: adding multiple 0 to the right
# Special cases:
# a) xlnet pads on the left and uses "4" for padding token_type_ids
if tokenizer.__class__.__name__ == "XLNetTokenizer":
pad_on_left = True
segment_ids = pad(segment_ids, max_seq_len, 4, pad_on_left=pad_on_left)
else:
pad_on_left = False
segment_ids = pad(segment_ids, max_seq_len, 0, pad_on_left=pad_on_left)
input_ids = pad(input_ids, max_seq_len, tokenizer.pad_token_id, pad_on_left=pad_on_left)
padding_mask = pad(padding_mask, max_seq_len, 0, pad_on_left=pad_on_left)
initial_mask = pad(initial_mask, max_seq_len, 0, pad_on_left=pad_on_left)
if label_ids:
label_ids = pad(label_ids, max_seq_len, 0, pad_on_left=pad_on_left)
feature_dict = {
"input_ids": input_ids,
"padding_mask": padding_mask,
"segment_ids": segment_ids,
"initial_mask": initial_mask,
}
if label_ids:
feature_dict[label_tensor_name] = label_ids
return [feature_dict]
def samples_to_features_bert_lm(sample, max_seq_len, tokenizer, next_sent_pred=True):
"""
Convert a raw sample (pair of sentences as tokenized strings) into a proper training sample with
IDs, LM labels, padding_mask, CLS and SEP tokens etc.
:param sample: Sample, containing sentence input as strings and is_next label
:type sample: Sample
:param max_seq_len: Maximum length of sequence.
:type max_seq_len: int
:param tokenizer: Tokenizer
:return: InputFeatures, containing all inputs and labels of one sample as IDs (as used for model training)
"""
if next_sent_pred:
tokens_a = sample.tokenized["text_a"]["tokens"]
tokens_b = sample.tokenized["text_b"]["tokens"]
# mask random words
tokens_a, t1_label = mask_random_words(tokens_a, tokenizer.vocab,
token_groups=sample.tokenized["text_a"]["start_of_word"])
tokens_b, t2_label = mask_random_words(tokens_b, tokenizer.vocab,
token_groups=sample.tokenized["text_b"]["start_of_word"])
if tokenizer.is_fast:
# Detokenize input as fast tokenizer can't handle tokenized input
tokens_a = " ".join(tokens_a)
tokens_a = re.sub(r"(^|\s)(##)", "", tokens_a)
tokens_b = " ".join(tokens_b)
tokens_b = re.sub(r"(^|\s)(##)", "", tokens_b)
# convert lm labels to ids
t1_label_ids = [-1 if tok == '' else tokenizer.convert_tokens_to_ids(tok) for tok in t1_label]
t2_label_ids = [-1 if tok == '' else tokenizer.convert_tokens_to_ids(tok) for tok in t2_label]
lm_label_ids = t1_label_ids + t2_label_ids
# Convert is_next_label: Note that in Bert, is_next_labelid = 0 is used for next_sentence=true!
if sample.clear_text["nextsentence_label"]:
is_next_label_id = [0]
else:
is_next_label_id = [1]
else:
tokens_a = sample.tokenized["text_a"]["tokens"]
tokens_b = None
tokens_a, t1_label = mask_random_words(tokens_a, tokenizer.vocab,
token_groups=sample.tokenized["text_a"]["start_of_word"])
if tokenizer.is_fast:
# Detokenize input as fast tokenizer can't handle tokenized input
tokens_a = " ".join(tokens_a)
tokens_a = re.sub(r"(^|\s)(##)", "", tokens_a)
# convert lm labels to ids
lm_label_ids = [-1 if tok == '' else tokenizer.convert_tokens_to_ids(tok) for tok in t1_label]
if tokenizer.is_fast:
inputs = tokenizer(text=tokens_a,
text_pair=tokens_b,
add_special_tokens=True,
return_special_tokens_mask=True,
return_token_type_ids=True)
seq_b_len = len(sample.tokenized["text_b"]["tokens"]) if "text_b" in sample.tokenized else 0
if (len(inputs["input_ids"]) - inputs["special_tokens_mask"].count(1)) != \
(len(sample.tokenized["text_a"]["tokens"]) + seq_b_len):
logger.error(f"FastTokenizer encoded sample {sample.clear_text['text']} to "
f"{len(inputs['input_ids']) - inputs['special_tokens_mask'].count(1)} tokens, which differs "
f"from number of tokens produced in tokenize_with_metadata(). \n"
f"Further processing is likely to be wrong.")
else:
# encode string tokens to input_ids and add special tokens
inputs = tokenizer.encode_plus(text=tokens_a,
text_pair=tokens_b,
add_special_tokens=True,
truncation=False,
truncation_strategy='do_not_truncate',
# We've already truncated our tokens before
return_special_tokens_mask=True,
return_token_type_ids=True
)
input_ids, segment_ids, special_tokens_mask = inputs["input_ids"], inputs["token_type_ids"], inputs[
"special_tokens_mask"]
# account for special tokens (CLS, SEP, SEP..) in lm_label_ids
lm_label_ids = insert_at_special_tokens_pos(lm_label_ids, special_tokens_mask, insert_element=-1)
# The mask has 1 for real tokens and 0 for padding tokens. Only real
# tokens are attended to.
padding_mask = [1] * len(input_ids)
# Zero-pad up to the sequence length.
# Padding up to the sequence length.
# Normal case: adding multiple 0 to the right
# Special cases:
# a) xlnet pads on the left and uses "4" for padding token_type_ids
if tokenizer.__class__.__name__ == "XLNetTokenizer":
pad_on_left = True
segment_ids = pad(segment_ids, max_seq_len, 4, pad_on_left=pad_on_left)
else:
pad_on_left = False
segment_ids = pad(segment_ids, max_seq_len, 0, pad_on_left=pad_on_left)
input_ids = pad(input_ids, max_seq_len, tokenizer.pad_token_id, pad_on_left=pad_on_left)
padding_mask = pad(padding_mask, max_seq_len, 0, pad_on_left=pad_on_left)
lm_label_ids = pad(lm_label_ids, max_seq_len, -1, pad_on_left=pad_on_left)
feature_dict = {
"input_ids": input_ids,
"padding_mask": padding_mask,
"segment_ids": segment_ids,
"lm_label_ids": lm_label_ids,
}
if next_sent_pred:
feature_dict["nextsentence_label_ids"] = is_next_label_id
assert len(input_ids) == max_seq_len
assert len(padding_mask) == max_seq_len
assert len(segment_ids) == max_seq_len
assert len(lm_label_ids) == max_seq_len
return [feature_dict]
def samples_to_features_bert_lm(sample,
max_seq_len,
tokenizer,
next_sent_pred=True):
"""
Convert a raw sample (pair of sentences as tokenized strings) into a proper training sample with
IDs, LM labels, padding_mask, CLS and SEP tokens etc.
:param sample: Sample, containing sentence input as strings and is_next label
:type sample: Sample
:param max_seq_len: Maximum length of sequence.
:type max_seq_len: int
:param tokenizer: Tokenizer
:return: InputFeatures, containing all inputs and labels of one sample as IDs (as used for model training)
"""
if next_sent_pred:
tokens_a = sample.tokenized["text_a"]["tokens"]
tokens_b = sample.tokenized["text_b"]["tokens"]
# mask random words
tokens_a, t1_label = mask_random_words(
tokens_a,
tokenizer.vocab,
token_groups=sample.tokenized["text_a"]["start_of_word"])
tokens_b, t2_label = mask_random_words(
tokens_b,
tokenizer.vocab,
token_groups=sample.tokenized["text_b"]["start_of_word"])
# convert lm labels to ids
t1_label_ids = [
-1 if tok == '' else tokenizer.vocab[tok] for tok in t1_label
]
t2_label_ids = [
-1 if tok == '' else tokenizer.vocab[tok] for tok in t2_label
]
lm_label_ids = t1_label_ids + t2_label_ids
# Convert is_next_label: Note that in Bert, is_next_labelid = 0 is used for next_sentence=true!
if sample.clear_text["nextsentence_label"]:
is_next_label_id = [0]
else:
is_next_label_id = [1]
else:
tokens_a = sample.tokenized["text_a"]["tokens"]
tokens_b = None
tokens_a, t1_label = mask_random_words(
tokens_a,
tokenizer.vocab,
token_groups=sample.tokenized["text_a"]["start_of_word"])
# convert lm labels to ids
lm_label_ids = [
-1 if tok == '' else tokenizer.vocab[tok] for tok in t1_label
]
# encode string tokens to input_ids and add special tokens
inputs = tokenizer.encode_plus(text=tokens_a,
text_pair=tokens_b,
add_special_tokens=True,
max_length=max_seq_len,
truncation_strategy='do_not_truncate'
# We've already truncated our tokens before
)
input_ids, segment_ids, special_tokens_mask = inputs["input_ids"], inputs[
"token_type_ids"], inputs["special_tokens_mask"]
# account for special tokens (CLS, SEP, SEP..) in lm_label_ids
lm_label_ids = insert_at_special_tokens_pos(lm_label_ids,
special_tokens_mask,
insert_element=-1)
# The mask has 1 for real tokens and 0 for padding tokens. Only real
# tokens are attended to.
padding_mask = [1] * len(input_ids)
# Zero-pad up to the sequence length.
# Padding up to the sequence length.
# Normal case: adding multiple 0 to the right
# Special cases:
# a) xlnet pads on the left and uses "4" for padding token_type_ids
if tokenizer.__class__.__name__ == "XLNetTokenizer":
pad_on_left = True
segment_ids = pad(segment_ids, max_seq_len, 4, pad_on_left=pad_on_left)
else:
pad_on_left = False
segment_ids = pad(segment_ids, max_seq_len, 0, pad_on_left=pad_on_left)
input_ids = pad(input_ids,
max_seq_len,
tokenizer.pad_token_id,
pad_on_left=pad_on_left)
padding_mask = pad(padding_mask, max_seq_len, 0, pad_on_left=pad_on_left)
lm_label_ids = pad(lm_label_ids, max_seq_len, -1, pad_on_left=pad_on_left)
feature_dict = {
"input_ids": input_ids,
"padding_mask": padding_mask,
"segment_ids": segment_ids,
"lm_label_ids": lm_label_ids,
}
if next_sent_pred:
feature_dict["nextsentence_label_ids"] = is_next_label_id
assert len(input_ids) == max_seq_len
assert len(padding_mask) == max_seq_len
assert len(segment_ids) == max_seq_len
assert len(lm_label_ids) == max_seq_len
return [feature_dict]
