mirror of https://github.com/explosion/spaCy.git
101 lines
3.3 KiB
Python
101 lines
3.3 KiB
Python
# coding: utf8
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from __future__ import unicode_literals
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from thinc.t2v import Pooling, max_pool, mean_pool
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from thinc.neural._classes.difference import Siamese, CauchySimilarity
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from .pipes import Pipe
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from .._ml import link_vectors_to_models
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class SentenceSegmenter(object):
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"""A simple spaCy hook, to allow custom sentence boundary detection logic
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(that doesn't require the dependency parse). To change the sentence
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boundary detection strategy, pass a generator function `strategy` on
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initialization, or assign a new strategy to the .strategy attribute.
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Sentence detection strategies should be generators that take `Doc` objects
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and yield `Span` objects for each sentence.
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"""
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name = "sentencizer"
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def __init__(self, vocab, strategy=None):
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self.vocab = vocab
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if strategy is None or strategy == "on_punct":
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strategy = self.split_on_punct
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self.strategy = strategy
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def __call__(self, doc):
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doc.user_hooks["sents"] = self.strategy
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return doc
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@staticmethod
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def split_on_punct(doc):
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start = 0
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seen_period = False
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for i, token in enumerate(doc):
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if seen_period and not token.is_punct:
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yield doc[start : token.i]
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start = token.i
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seen_period = False
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elif token.text in [".", "!", "?"]:
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seen_period = True
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if start < len(doc):
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yield doc[start : len(doc)]
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class SimilarityHook(Pipe):
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"""
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Experimental: A pipeline component to install a hook for supervised
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similarity into `Doc` objects. Requires a `Tensorizer` to pre-process
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documents. The similarity model can be any object obeying the Thinc `Model`
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interface. By default, the model concatenates the elementwise mean and
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elementwise max of the two tensors, and compares them using the
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Cauchy-like similarity function from Chen (2013):
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>>> similarity = 1. / (1. + (W * (vec1-vec2)**2).sum())
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Where W is a vector of dimension weights, initialized to 1.
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"""
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name = "similarity"
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def __init__(self, vocab, model=True, **cfg):
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self.vocab = vocab
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self.model = model
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self.cfg = dict(cfg)
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@classmethod
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def Model(cls, length):
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return Siamese(Pooling(max_pool, mean_pool), CauchySimilarity(length))
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def __call__(self, doc):
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"""Install similarity hook"""
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doc.user_hooks["similarity"] = self.predict
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return doc
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def pipe(self, docs, **kwargs):
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for doc in docs:
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yield self(doc)
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def predict(self, doc1, doc2):
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self.require_model()
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return self.model.predict([(doc1, doc2)])
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def update(self, doc1_doc2, golds, sgd=None, drop=0.0):
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self.require_model()
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sims, bp_sims = self.model.begin_update(doc1_doc2, drop=drop)
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def begin_training(self, _=tuple(), pipeline=None, sgd=None, **kwargs):
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"""Allocate model, using width from tensorizer in pipeline.
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gold_tuples (iterable): Gold-standard training data.
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pipeline (list): The pipeline the model is part of.
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"""
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if self.model is True:
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self.model = self.Model(pipeline[0].model.nO)
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link_vectors_to_models(self.vocab)
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if sgd is None:
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sgd = self.create_optimizer()
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return sgd
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