spaCy/spacy/ml/models/coref.py
Paul O'Leary McCann 7c42a8c90a Migrate coref code
This includes the coref code that was being tested separately, modified
to work in spaCy. It hasn't been tested yet and presumably still needs
fixes.

In particular, the evaluation code is currently omitted. It's unclear at
the moment whether we want to use a complex scorer similar to the
official one, or a simpler scorer using more modern evaluation methods.
2021-05-15 21:36:10 +09:00

403 lines
13 KiB
Python

from dataclasses import dataclass
from thinc.api import Model, Linear, Relu, Dropout, chain, noop
from thinc.types import Floats2d, Floats1d, Ints2d, Ragged
from typing import List, Callable, Tuple
from ...tokens import Doc
from ...util import registry
from .coref_util import (
get_predicted_clusters,
get_candidate_mentions,
select_non_crossing_spans,
make_clean_doc,
create_gold_scores,
logsumexp,
topk,
)
@registry.architectures("spacy.Coref.v0")
def build_coref(
tok2vec: Model[List[Doc], List[Floats2d]],
get_mentions: Callable = get_candidate_mentions,
hidden: int = 1000,
dropout: float = 0.3,
mention_limit: int = 3900,
max_span_width: int = 20,
):
dim = tok2vec.get_dim("nO") * 3
span_embedder = build_span_embedder(get_mentions, max_span_width)
with Model.define_operators({">>": chain, "&": tuplify}):
mention_scorer = (
Linear(nI=dim, nO=hidden)
>> Relu(nI=hidden, nO=hidden)
>> Dropout(dropout)
>> Linear(nI=hidden, nO=1)
)
mention_scorer.initialize()
bilinear = Linear(nI=dim, nO=dim) >> Dropout(dropout)
bilinear.initialize()
ms = build_take_vecs() >> mention_scorer
model = (
(tok2vec & noop())
>> span_embedder
>> (ms & noop())
>> build_coarse_pruner(mention_limit)
>> build_ant_scorer(bilinear, Dropout(dropout))
)
return model
# TODO replace this with thinc version once PR is in
def tuplify(layer1: Model, layer2: Model, *layers) -> Model:
layers = (layer1, layer2) + layers
names = [layer.name for layer in layers]
return Model(
"tuple(" + ", ".join(names) + ")",
tuplify_forward,
layers=layers,
)
def tuplify_forward(model, X, is_train):
Ys = []
backprops = []
for layer in model.layers:
Y, backprop = layer(X, is_train)
Ys.append(Y)
backprops.append(backprop)
def backprop_tuplify(dYs):
dXs = [bp(dY) for bp, dY in zip(backprops, dYs)]
dX = dXs[0]
for dx in dXs[1:]:
dX += dx
return dX
return tuple(Ys), backprop_tuplify
@dataclass
class SpanEmbeddings:
indices: Ints2d # Array with 2 columns (for start and end index)
vectors: Ragged # Ragged[Floats2d] # One vector per span
# NB: We assume that the indices refer to a concatenated Floats2d that
# has one row per token in the *batch* of documents. This makes it unambiguous
# which row is in which document, because if the lengths are e.g. [10, 5],
# a span starting at 11 must be starting at token 2 of doc 1. A bug could
# potentially cause you to have a span which crosses a doc boundary though,
# which would be bad.
# The lengths in the Ragged are not the tokens per doc, but the number of
# mentions per doc.
def __add__(self, right):
out = self.vectors.data + right.vectors.data
return SpanEmbeddings(self.indices, Ragged(out, self.vectors.lengths))
def __iadd__(self, right):
self.vectors.data += right.vectors.data
return self
# model converting a Doc/Mention to span embeddings
# get_mentions: Callable[Doc, Pairs[int]]
def build_span_embedder(
get_mentions: Callable,
max_span_width: int = 20,
) -> Model[Tuple[List[Floats2d], List[Doc]], SpanEmbeddings]:
return Model(
"SpanEmbedding",
forward=span_embeddings_forward,
attrs={
"get_mentions": get_mentions,
# XXX might be better to make this an implicit parameter in the
# mention generator
"max_span_width": max_span_width,
},
)
def span_embeddings_forward(
model, inputs: Tuple[List[Floats2d], List[Doc]], is_train
) -> SpanEmbeddings:
ops = model.ops
xp = ops.xp
tokvecs, docs = inputs
dim = tokvecs[0].shape[1]
get_mentions = model.attrs["get_mentions"]
max_span_width = model.attrs["max_span_width"]
mentions = ops.alloc2i(0, 2)
total_length = 0
docmenlens = [] # number of mentions per doc
for doc in docs:
starts, ends = get_mentions(doc, max_span_width)
docmenlens.append(len(starts))
cments = ops.asarray2i([starts, ends]).transpose()
mentions = xp.concatenate((mentions, cments + total_length))
total_length += len(doc)
# TODO support attention here
tokvecs = xp.concatenate(tokvecs)
spans = [tokvecs[ii:jj] for ii, jj in mentions.tolist()]
avgs = [xp.mean(ss, axis=0) for ss in spans]
spanvecs = ops.asarray2f(avgs)
# first and last token embeds
starts = [tokvecs[ii] for ii in mentions[:, 0]]
ends = [tokvecs[jj] for jj in mentions[:, 1]]
starts = ops.asarray2f(starts)
ends = ops.asarray2f(ends)
concat = xp.concatenate((starts, ends, spanvecs), 1)
embeds = Ragged(concat, docmenlens)
def backprop_span_embed(dY: SpanEmbeddings) -> Tuple[List[Floats2d], List[Doc]]:
oweights = []
odocs = []
offset = 0
tokoffset = 0
for indoc, mlen in zip(docs, dY.vectors.lengths):
hi = offset + mlen
hitok = tokoffset + len(indoc)
odocs.append(indoc) # no change
vecs = dY.vectors.data[offset:hi]
starts = vecs[:, :dim]
ends = vecs[:, dim : 2 * dim]
spanvecs = vecs[:, 2 * dim :]
out = model.ops.alloc2f(len(indoc), dim)
for ii, (start, end) in enumerate(dY.indices[offset:hi]):
# adjust indexes to align with doc
start -= tokoffset
end -= tokoffset
out[start] += starts[ii]
out[end] += ends[ii]
out[start:end] += spanvecs[ii]
oweights.append(out)
offset = hi
tokoffset = hitok
return oweights, odocs
return SpanEmbeddings(mentions, embeds), backprop_span_embed
def build_coarse_pruner(
mention_limit: int,
) -> Model[SpanEmbeddings, SpanEmbeddings]:
model = Model(
"CoarsePruner",
forward=coarse_prune,
attrs={
"mention_limit": mention_limit,
},
)
return model
def coarse_prune(
model, inputs: Tuple[Floats1d, SpanEmbeddings], is_train
) -> SpanEmbeddings:
"""Given scores for mention, output the top non-crossing mentions.
Mentions can contain other mentions, but candidate mentions cannot cross each other.
"""
rawscores, spanembeds = inputs
scores = rawscores.squeeze()
mention_limit = model.attrs["mention_limit"]
# XXX: Issue here. Don't need docs to find crossing spans, but might for the limits.
# In old code the limit can be:
# - hard number per doc
# - ratio of tokens in the doc
offset = 0
selected = []
sellens = []
for menlen in spanembeds.vectors.lengths:
hi = offset + menlen
cscores = scores[offset:hi]
# negate it so highest numbers come first
tops = (model.ops.xp.argsort(-1 * cscores)).tolist()
starts = spanembeds.indices[offset:hi, 0].tolist()
ends = spanembeds.indices[offset:hi:, 1].tolist()
# csel is a 1d integer list
csel = select_non_crossing_spans(tops, starts, ends, mention_limit)
# add the offset so these indices are absolute
csel = [ii + offset for ii in csel]
# this should be constant because short choices are padded
sellens.append(len(csel))
selected += csel
offset += menlen
selected = model.ops.asarray1i(selected)
top_spans = spanembeds.indices[selected]
top_vecs = spanembeds.vectors.data[selected]
out = SpanEmbeddings(top_spans, Ragged(top_vecs, sellens))
def coarse_prune_backprop(
dY: Tuple[Floats1d, SpanEmbeddings]
) -> Tuple[Floats1d, SpanEmbeddings]:
ll = spanembeds.indices.shape[0]
dYscores, dYembeds = dY
dXscores = model.ops.alloc1f(ll)
dXscores[selected] = dYscores.squeeze()
dXvecs = model.ops.alloc2f(*spanembeds.vectors.data.shape)
dXvecs[selected] = dYembeds.vectors.data
rout = Ragged(dXvecs, out.vectors.lengths)
dXembeds = SpanEmbeddings(spanembeds.indices, rout)
# inflate for mention scorer
dXscores = model.ops.xp.expand_dims(dXscores, 1)
return (dXscores, dXembeds)
return (scores[selected], out), coarse_prune_backprop
def build_take_vecs() -> Model[SpanEmbeddings, Floats2d]:
# this just gets vectors out of spanembeddings
# XXX Might be better to convert SpanEmbeddings to a tuple and use with_getitem
return Model("TakeVecs", forward=take_vecs_forward)
def take_vecs_forward(model, inputs: SpanEmbeddings, is_train) -> Floats2d:
def backprop(dY: Floats2d) -> SpanEmbeddings:
vecs = Ragged(dY, inputs.vectors.lengths)
return SpanEmbeddings(inputs.indices, vecs)
return inputs.vectors.data, backprop
def build_ant_scorer(
bilinear, dropout, ant_limit=50
) -> Model[Tuple[Floats1d, SpanEmbeddings], List[Floats2d]]:
return Model(
"AntScorer",
forward=ant_scorer_forward,
layers=[bilinear, dropout],
attrs={
"ant_limit": ant_limit,
},
)
def ant_scorer_forward(
model, inputs: Tuple[Floats1d, SpanEmbeddings], is_train
) -> Tuple[List[Tuple[Floats2d, Ints2d]], Ints2d]:
ops = model.ops
xp = ops.xp
ant_limit = model.attrs["ant_limit"]
# this contains the coarse bilinear in coref-hoi
# coarse bilinear is a single layer linear network
# TODO make these proper refs
bilinear = model.layers[0]
dropout = model.layers[1]
# XXX Note on dimensions: This won't work as a ragged because the floats2ds
# are not all the same dimentions. Each floats2d is a square in the size of
# the number of antecedents in the document. Actually, that will have the
# same size if antecedents are padded... Needs checking.
mscores, sembeds = inputs
vecs = sembeds.vectors # ragged
offset = 0
backprops = []
out = []
for ll in vecs.lengths:
hi = offset + ll
# each iteration is one doc
# first calculate the pairwise product scores
cvecs = vecs.data[offset:hi]
source, source_b = bilinear(cvecs, is_train)
target, target_b = dropout(cvecs, is_train)
pw_prod = xp.matmul(source, target.T)
# now calculate the pairwise mention scores
ms = mscores[offset:hi].squeeze()
pw_sum = xp.expand_dims(ms, 1) + xp.expand_dims(ms, 0)
# make a mask so antecedents precede referrents
ant_range = xp.arange(0, cvecs.shape[0])
# with xp.errstate(divide="ignore"):
# mask = xp.log(
# (xp.expand_dims(ant_range, 1) - xp.expand_dims(ant_range, 0)) >= 1
# ).astype(float)
mask = xp.log(
(xp.expand_dims(ant_range, 1) - xp.expand_dims(ant_range, 0)) >= 1
).astype(float)
scores = pw_prod + pw_sum + mask
top_scores, top_scores_idx = topk(xp, scores, ant_limit)
out.append((top_scores, top_scores_idx))
# In the full model these scores can be further refined. In the current
# state of this model we're done here, so this pruning is less important,
# but it's still helpful for reducing memory usage (since scores can be
# garbage collected when the loop exits).
offset += ll
backprops.append((source_b, target_b, source, target))
def backprop(
dYs: Tuple[List[Tuple[Floats2d, Ints2d]], Ints2d]
) -> Tuple[Floats2d, SpanEmbeddings]:
dYscores, dYembeds = dYs
dXembeds = Ragged(ops.alloc2f(*vecs.data.shape), vecs.lengths)
dXscores = ops.alloc1f(*mscores.shape)
offset = 0
for dy, (source_b, target_b, source, target), ll in zip(
dYscores, backprops, vecs.lengths
):
# I'm not undoing the operations in the right order here.
dyscore, dyidx = dy
# the full score grid is square
fullscore = ops.alloc2f(ll, ll)
# cupy has no put_along_axis
# xp.put_along_axis(fullscore, dyidx, dyscore, 1)
for ii, (ridx, rscores) in enumerate(zip(dyidx, dyscore)):
fullscore[ii][ridx] = rscores
dS = source_b(fullscore @ target)
dT = target_b(fullscore @ source)
dXembeds.data[offset : offset + ll] = dS + dT
# The gradient can be distributed over all the rows and columns here,
# so aggregate it
section = dXscores[offset : offset + ll]
for ii in range(ll):
section[ii] = fullscore[:, ii].sum() + fullscore[ii, :].sum()
offset += ll
# make it fit back into the linear
dXscores = xp.expand_dims(dXscores, 1)
return (dXscores, SpanEmbeddings(sembeds.indices, dXembeds))
return (out, sembeds.indices), backprop