spaCy/spacy/tokens/_retokenize.pyx

410 lines
17 KiB
Cython

# coding: utf8
# cython: infer_types=True
# cython: bounds_check=False
# cython: profile=True
from __future__ import unicode_literals
from libc.string cimport memcpy, memset
from libc.stdlib cimport malloc, free
from cymem.cymem cimport Pool
from thinc.neural.util import get_array_module
import numpy
from .doc cimport Doc, set_children_from_heads, token_by_start, token_by_end
from .span cimport Span
from .token cimport Token
from ..lexeme cimport Lexeme, EMPTY_LEXEME
from ..structs cimport LexemeC, TokenC
from ..attrs cimport TAG
from .underscore import is_writable_attr
from ..attrs import intify_attrs
from ..util import SimpleFrozenDict
from ..errors import Errors
from ..strings import get_string_id
cdef class Retokenizer:
"""Helper class for doc.retokenize() context manager.
DOCS: https://spacy.io/api/doc#retokenize
USAGE: https://spacy.io/usage/linguistic-features#retokenization
"""
cdef Doc doc
cdef list merges
cdef list splits
cdef set tokens_to_merge
def __init__(self, doc):
self.doc = doc
self.merges = []
self.splits = []
self.tokens_to_merge = set()
def merge(self, Span span, attrs=SimpleFrozenDict()):
"""Mark a span for merging. The attrs will be applied to the resulting
token.
span (Span): The span to merge.
attrs (dict): Attributes to set on the merged token.
DOCS: https://spacy.io/api/doc#retokenizer.merge
"""
for token in span:
if token.i in self.tokens_to_merge:
raise ValueError(Errors.E102.format(token=repr(token)))
self.tokens_to_merge.add(token.i)
if "_" in attrs: # Extension attributes
extensions = attrs["_"]
_validate_extensions(extensions)
attrs = {key: value for key, value in attrs.items() if key != "_"}
attrs = intify_attrs(attrs, strings_map=self.doc.vocab.strings)
attrs["_"] = extensions
else:
attrs = intify_attrs(attrs, strings_map=self.doc.vocab.strings)
self.merges.append((span, attrs))
def split(self, Token token, orths, heads, attrs=SimpleFrozenDict()):
"""Mark a Token for splitting, into the specified orths. The attrs
will be applied to each subtoken.
token (Token): The token to split.
orths (list): The verbatim text of the split tokens. Needs to match the
text of the original token.
heads (list): List of token or `(token, subtoken)` tuples specifying the
tokens to attach the newly split subtokens to.
attrs (dict): Attributes to set on all split tokens. Attribute names
mapped to list of per-token attribute values.
DOCS: https://spacy.io/api/doc#retokenizer.split
"""
if ''.join(orths) != token.text:
raise ValueError(Errors.E117.format(new=''.join(orths), old=token.text))
if "_" in attrs: # Extension attributes
extensions = attrs["_"]
for extension in extensions:
_validate_extensions(extension)
attrs = {key: value for key, value in attrs.items() if key != "_"}
# NB: Since we support {"KEY": [value, value]} syntax here, this
# will only "intify" the keys, not the values
attrs = intify_attrs(attrs, strings_map=self.doc.vocab.strings)
attrs["_"] = extensions
else:
# NB: Since we support {"KEY": [value, value]} syntax here, this
# will only "intify" the keys, not the values
attrs = intify_attrs(attrs, strings_map=self.doc.vocab.strings)
head_offsets = []
for head in heads:
if isinstance(head, Token):
head_offsets.append((head.idx, 0))
else:
head_offsets.append((head[0].idx, head[1]))
self.splits.append((token.idx, orths, head_offsets, attrs))
def __enter__(self):
self.merges = []
self.splits = []
return self
def __exit__(self, *args):
# Do the actual merging here
if len(self.merges) >= 1:
_merge(self.doc, self.merges)
# Iterate in order, to keep things simple.
for start_char, orths, heads, attrs in sorted(self.splits):
# Resolve token index
token_index = token_by_start(self.doc.c, self.doc.length, start_char)
# Check we're still able to find tokens starting at the character offsets
# referred to in the splits. If we merged these tokens previously, we
# have to raise an error
if token_index == -1:
raise IndexError(Errors.E122)
head_indices = []
for head_char, subtoken in heads:
head_index = token_by_start(self.doc.c, self.doc.length, head_char)
if head_index == -1:
raise IndexError(Errors.E123)
# We want to refer to the token index of the head *after* the
# mergery. We need to account for the extra tokens introduced.
# e.g., let's say we have [ab, c] and we want a and b to depend
# on c. The correct index for c will be 2, not 1.
if head_index > token_index:
head_index += len(orths)-1
head_indices.append(head_index+subtoken)
_split(self.doc, token_index, orths, head_indices, attrs)
def _merge(Doc doc, merges):
"""Retokenize the document, such that the spans described in 'merges'
are merged into a single token. This method assumes that the merges
are in the same order at which they appear in the doc, and that merges
do not intersect each other in any way.
merges: Tokens to merge, and corresponding attributes to assign to the
merged token. By default, attributes are inherited from the
syntactic root of the span.
RETURNS (Token): The first newly merged token.
"""
cdef int i, merge_index, start, end, token_index
cdef Span span
cdef const LexemeC* lex
cdef TokenC* token
cdef Pool mem = Pool()
tokens = <TokenC**>mem.alloc(len(merges), sizeof(TokenC))
spans = []
def _get_start(merge):
return merge[0].start
merges.sort(key=_get_start)
for merge_index, (span, attributes) in enumerate(merges):
start = span.start
end = span.end
spans.append(span)
# House the new merged token where it starts
token = &doc.c[start]
# Initially set attributes to attributes of span root
token.tag = doc.c[span.root.i].tag
token.pos = doc.c[span.root.i].pos
token.morph = doc.c[span.root.i].morph
token.ent_iob = doc.c[span.root.i].ent_iob
token.ent_type = doc.c[span.root.i].ent_type
merged_iob = token.ent_iob
# If span root is part of an entity, merged token is B-ENT
if token.ent_iob in (1, 3):
merged_iob = 3
# If start token is I-ENT and previous token is of the same
# type, then I-ENT (could check I-ENT from start to span root)
if doc.c[start].ent_iob == 1 and start > 0 \
and doc.c[start].ent_type == token.ent_type \
and doc.c[start - 1].ent_type == token.ent_type:
merged_iob = 1
token.ent_iob = merged_iob
# Unset attributes that don't match new token
token.lemma = 0
token.norm = 0
tokens[merge_index] = token
# Resize the doc.tensor, if it's set. Let the last row for each token stand
# for the merged region. To do this, we create a boolean array indicating
# whether the row is to be deleted, then use numpy.delete
if doc.tensor is not None and doc.tensor.size != 0:
doc.tensor = _resize_tensor(doc.tensor,
[(m[0].start, m[0].end) for m in merges])
# Memorize span roots and sets dependencies of the newly merged
# tokens to the dependencies of their roots.
span_roots = []
for i, span in enumerate(spans):
span_roots.append(span.root.i)
tokens[i].dep = span.root.dep
# We update token.lex after keeping span root and dep, since
# setting token.lex will change span.start and span.end properties
# as it modifies the character offsets in the doc
for token_index, (span, attributes) in enumerate(merges):
new_orth = ''.join([t.text_with_ws for t in spans[token_index]])
if spans[token_index][-1].whitespace_:
new_orth = new_orth[:-len(spans[token_index][-1].whitespace_)]
token = tokens[token_index]
lex = doc.vocab.get(doc.mem, new_orth)
token.lex = lex
# We set trailing space here too
token.spacy = doc.c[spans[token_index].end-1].spacy
py_token = span[0]
# Assign attributes
for attr_name, attr_value in attributes.items():
if attr_name == "_": # Set extension attributes
for ext_attr_key, ext_attr_value in attr_value.items():
py_token._.set(ext_attr_key, ext_attr_value)
elif attr_name == TAG:
doc.vocab.morphology.assign_tag(token, attr_value)
else:
# Set attributes on both token and lexeme to take care of token
# attribute vs. lexical attribute without having to enumerate
# them. If an attribute name is not valid, set_struct_attr will
# ignore it.
Token.set_struct_attr(token, attr_name, attr_value)
Lexeme.set_struct_attr(<LexemeC*>lex, attr_name, attr_value)
# Begin by setting all the head indices to absolute token positions
# This is easier to work with for now than the offsets
# Before thinking of something simpler, beware the case where a
# dependency bridges over the entity. Here the alignment of the
# tokens changes.
for i in range(doc.length):
doc.c[i].head += i
# Set the head of the merged token from the Span
for i in range(len(merges)):
tokens[i].head = doc.c[span_roots[i]].head
# Adjust deps before shrinking tokens
# Tokens which point into the merged token should now point to it
# Subtract the offset from all tokens which point to >= end
offsets = []
current_span_index = 0
current_offset = 0
for i in range(doc.length):
if current_span_index < len(spans) and i == spans[current_span_index].end:
# Last token was the last of the span
current_offset += (spans[current_span_index].end - spans[current_span_index].start) -1
current_span_index += 1
if current_span_index < len(spans) and \
spans[current_span_index].start <= i < spans[current_span_index].end:
offsets.append(spans[current_span_index].start - current_offset)
else:
offsets.append(i - current_offset)
for i in range(doc.length):
doc.c[i].head = offsets[doc.c[i].head]
# Now compress the token array
offset = 0
in_span = False
span_index = 0
for i in range(doc.length):
if in_span and i == spans[span_index].end:
# First token after a span
in_span = False
span_index += 1
if span_index < len(spans) and i == spans[span_index].start:
# First token in a span
doc.c[i - offset] = doc.c[i] # move token to its place
offset += (spans[span_index].end - spans[span_index].start) - 1
in_span = True
if not in_span:
doc.c[i - offset] = doc.c[i] # move token to its place
for i in range(doc.length - offset, doc.length):
memset(&doc.c[i], 0, sizeof(TokenC))
doc.c[i].lex = &EMPTY_LEXEME
doc.length -= offset
# ...And, set heads back to a relative position
for i in range(doc.length):
doc.c[i].head -= i
# Set the left/right children, left/right edges
set_children_from_heads(doc.c, doc.length)
# Make sure ent_iob remains consistent
make_iob_consistent(doc.c, doc.length)
# Return the merged Python object
return doc[spans[0].start]
def _resize_tensor(tensor, ranges):
delete = []
for start, end in ranges:
for i in range(start, end-1):
delete.append(i)
xp = get_array_module(tensor)
return xp.delete(tensor, delete, axis=0)
def _split(Doc doc, int token_index, orths, heads, attrs):
"""Retokenize the document, such that the token at
`doc[token_index]` is split into tokens with the orth 'orths'
token_index(int): token index of the token to split.
orths: IDs of the verbatim text content of the tokens to create
**attributes: Attributes to assign to each of the newly created tokens. By default,
attributes are inherited from the original token.
RETURNS (Token): The first newly created token.
"""
cdef int nb_subtokens = len(orths)
cdef const LexemeC* lex
cdef TokenC* token
cdef TokenC orig_token = doc.c[token_index]
cdef int orig_length = len(doc)
if(len(heads) != nb_subtokens):
raise ValueError(Errors.E115)
# First, make the dependencies absolutes
for i in range(doc.length):
doc.c[i].head += i
# Adjust dependencies, so they refer to post-split indexing
offset = nb_subtokens - 1
for i in range(doc.length):
if doc.c[i].head > token_index:
doc.c[i].head += offset
# Double doc.c max_length if necessary (until big enough for all new tokens)
while doc.length + nb_subtokens - 1 >= doc.max_length:
doc._realloc(doc.length * 2)
# Move tokens after the split to create space for the new tokens
doc.length = len(doc) + nb_subtokens -1
to_process_tensor = (doc.tensor is not None and doc.tensor.size != 0)
if to_process_tensor:
xp = get_array_module(doc.tensor)
doc.tensor = xp.append(doc.tensor, xp.zeros((nb_subtokens,doc.tensor.shape[1]), dtype="float32"), axis=0)
for token_to_move in range(orig_length - 1, token_index, -1):
doc.c[token_to_move + nb_subtokens - 1] = doc.c[token_to_move]
if to_process_tensor:
doc.tensor[token_to_move + nb_subtokens - 1] = doc.tensor[token_to_move]
# Host the tokens in the newly created space
cdef int idx_offset = 0
for i, orth in enumerate(orths):
token = &doc.c[token_index + i]
lex = doc.vocab.get(doc.mem, orth)
token.lex = lex
token.lemma = 0 # reset lemma
if to_process_tensor:
# setting the tensors of the split tokens to array of zeros
doc.tensor[token_index + i] = xp.zeros((1,doc.tensor.shape[1]), dtype="float32")
# Update the character offset of the subtokens
if i != 0:
token.idx = orig_token.idx + idx_offset
idx_offset += len(orth)
# Set token.spacy to False for all non-last split tokens, and
# to origToken.spacy for the last token
if (i < nb_subtokens - 1):
token.spacy = False
else:
token.spacy = orig_token.spacy
# Make IOB consistent
if (orig_token.ent_iob == 3):
if i == 0:
token.ent_iob = 3
else:
token.ent_iob = 1
else:
# In all other cases subtokens inherit iob from origToken
token.ent_iob = orig_token.ent_iob
# Apply attrs to each subtoken
for attr_name, attr_values in attrs.items():
for i, attr_value in enumerate(attr_values):
token = &doc.c[token_index + i]
if attr_name == "_":
for ext_attr_key, ext_attr_value in attr_value.items():
doc[token_index + i]._.set(ext_attr_key, ext_attr_value)
# NB: We need to call get_string_id here because only the keys are
# "intified" (since we support "KEY": [value, value] syntax here).
elif attr_name == TAG:
doc.vocab.morphology.assign_tag(token, get_string_id(attr_value))
else:
# Set attributes on both token and lexeme to take care of token
# attribute vs. lexical attribute without having to enumerate
# them. If an attribute name is not valid, set_struct_attr will
# ignore it.
Token.set_struct_attr(token, attr_name, get_string_id(attr_value))
Lexeme.set_struct_attr(<LexemeC*>token.lex, attr_name, get_string_id(attr_value))
# Assign correct dependencies to the inner token
for i, head in enumerate(heads):
doc.c[token_index + i].head = head
# Transform the dependencies into relative ones again
for i in range(doc.length):
doc.c[i].head -= i
# set children from head
set_children_from_heads(doc.c, doc.length)
def _validate_extensions(extensions):
if not isinstance(extensions, dict):
raise ValueError(Errors.E120.format(value=repr(extensions)))
for key, value in extensions.items():
# Get the extension and make sure it's available and writable
extension = Token.get_extension(key)
if not extension: # Extension attribute doesn't exist
raise ValueError(Errors.E118.format(attr=key))
if not is_writable_attr(extension):
raise ValueError(Errors.E119.format(attr=key))
cdef make_iob_consistent(TokenC* tokens, int length):
cdef int i
if tokens[0].ent_iob == 1:
tokens[0].ent_iob = 3
for i in range(1, length):
if tokens[i].ent_iob == 1 and tokens[i - 1].ent_type != tokens[i].ent_type:
tokens[i].ent_iob = 3