spaCy/spacy/ml/models/textcat.py
2020-06-20 14:15:04 +02:00

166 lines
6.2 KiB
Python

from thinc.api import Model, reduce_mean, Linear, list2ragged, Logistic
from thinc.api import ParametricAttention, chain, concatenate, clone, Dropout
from thinc.api import SparseLinear, Softmax, softmax_activation, Maxout
from thinc.api import reduce_sum, Relu, residual, expand_window, HashEmbed
from thinc.api import with_ragged, with_array, with_cpu, uniqued, FeatureExtractor
from ..spacy_vectors import SpacyVectors
from ... import util
from ...attrs import ID, ORTH, PREFIX, SUFFIX, SHAPE, LOWER
from ...util import registry
from ..extract_ngrams import extract_ngrams
@registry.architectures.register("spacy.TextCatCNN.v1")
def build_simple_cnn_text_classifier(tok2vec, exclusive_classes, nO=None):
"""
Build a simple CNN text classifier, given a token-to-vector model as inputs.
If exclusive_classes=True, a softmax non-linearity is applied, so that the
outputs sum to 1. If exclusive_classes=False, a logistic non-linearity
is applied instead, so that outputs are in the range [0, 1].
"""
with Model.define_operators({">>": chain}):
if exclusive_classes:
output_layer = Softmax(nO=nO, nI=tok2vec.get_dim("nO"))
model = tok2vec >> list2ragged() >> reduce_mean() >> output_layer
model.set_ref("output_layer", output_layer)
else:
linear_layer = Linear(nO=nO, nI=tok2vec.get_dim("nO"))
model = (
tok2vec >> list2ragged() >> reduce_mean() >> linear_layer >> Logistic()
)
model.set_ref("output_layer", linear_layer)
model.set_ref("tok2vec", tok2vec)
model.set_dim("nO", nO)
model.attrs["multi_label"] = not exclusive_classes
return model
@registry.architectures.register("spacy.TextCatBOW.v1")
def build_bow_text_classifier(exclusive_classes, ngram_size, no_output_layer, nO=None):
with Model.define_operators({">>": chain}):
sparse_linear = SparseLinear(nO)
model = extract_ngrams(ngram_size, attr=ORTH) >> sparse_linear
model = with_cpu(model, model.ops)
if not no_output_layer:
output_layer = softmax_activation() if exclusive_classes else Logistic()
model = model >> with_cpu(output_layer, output_layer.ops)
model.set_ref("output_layer", sparse_linear)
model.attrs["multi_label"] = not exclusive_classes
return model
@registry.architectures.register("spacy.TextCat.v1")
def build_text_classifier(
width,
embed_size,
pretrained_vectors,
exclusive_classes,
ngram_size,
window_size,
conv_depth,
dropout,
nO=None,
):
cols = [ORTH, LOWER, PREFIX, SUFFIX, SHAPE, ID]
with Model.define_operators({">>": chain, "|": concatenate, "**": clone}):
lower = HashEmbed(
nO=width, nV=embed_size, column=cols.index(LOWER), dropout=dropout
)
prefix = HashEmbed(
nO=width // 2, nV=embed_size, column=cols.index(PREFIX), dropout=dropout
)
suffix = HashEmbed(
nO=width // 2, nV=embed_size, column=cols.index(SUFFIX), dropout=dropout
)
shape = HashEmbed(
nO=width // 2, nV=embed_size, column=cols.index(SHAPE), dropout=dropout
)
width_nI = sum(layer.get_dim("nO") for layer in [lower, prefix, suffix, shape])
trained_vectors = FeatureExtractor(cols) >> with_array(
uniqued(
(lower | prefix | suffix | shape)
>> Maxout(nO=width, nI=width_nI, normalize=True),
column=cols.index(ORTH),
)
)
if pretrained_vectors:
nlp = util.load_model(pretrained_vectors)
vectors = nlp.vocab.vectors
vector_dim = vectors.data.shape[1]
static_vectors = SpacyVectors(vectors) >> with_array(
Linear(width, vector_dim)
)
vector_layer = trained_vectors | static_vectors
vectors_width = width * 2
else:
vector_layer = trained_vectors
vectors_width = width
tok2vec = vector_layer >> with_array(
Maxout(width, vectors_width, normalize=True)
>> residual(
(
expand_window(window_size=window_size)
>> Maxout(
nO=width, nI=width * ((window_size * 2) + 1), normalize=True
)
)
)
** conv_depth,
pad=conv_depth,
)
cnn_model = (
tok2vec
>> list2ragged()
>> ParametricAttention(width)
>> reduce_sum()
>> residual(Maxout(nO=width, nI=width))
>> Linear(nO=nO, nI=width)
>> Dropout(0.0)
)
linear_model = build_bow_text_classifier(
nO=nO,
ngram_size=ngram_size,
exclusive_classes=exclusive_classes,
no_output_layer=False,
)
nO_double = nO * 2 if nO else None
if exclusive_classes:
output_layer = Softmax(nO=nO, nI=nO_double)
else:
output_layer = Linear(nO=nO, nI=nO_double) >> Dropout(0.0) >> Logistic()
model = (linear_model | cnn_model) >> output_layer
model.set_ref("tok2vec", tok2vec)
if model.has_dim("nO") is not False:
model.set_dim("nO", nO)
model.set_ref("output_layer", linear_model.get_ref("output_layer"))
model.attrs["multi_label"] = not exclusive_classes
return model
@registry.architectures.register("spacy.TextCatLowData.v1")
def build_text_classifier_lowdata(width, pretrained_vectors, dropout, nO=None):
nlp = util.load_model(pretrained_vectors)
vectors = nlp.vocab.vectors
vector_dim = vectors.data.shape[1]
# Note, before v.3, this was the default if setting "low_data" and "pretrained_dims"
with Model.define_operators({">>": chain, "**": clone}):
model = (
SpacyVectors(vectors)
>> list2ragged()
>> with_ragged(0, Linear(width, vector_dim))
>> ParametricAttention(width)
>> reduce_sum()
>> residual(Relu(width, width)) ** 2
>> Linear(nO, width)
)
if dropout:
model = model >> Dropout(dropout)
model = model >> Logistic()
return model