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f997bceb07
This is a great tutorial, but I think it is weirdly explained in the current form. The largest part of the code is about implementing the actual sentiment analysis model, not about counting entities. (which is not even present in the `deep_learning_keras.py` script in `examples`)
214 lines
9.2 KiB
Plaintext
214 lines
9.2 KiB
Plaintext
//- 💫 DOCS > USAGE > DEEP LEARNING
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include ../../_includes/_mixins
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p
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| In this example, we'll be using #[+a("https://keras.io/") Keras], as
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| it's the most popular deep learning library for Python. Using Keras,
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| we will write a custom sentiment analysis model that predicts whether a
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| document is positive or negative. Then, we will use it to find which entities
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| are commonly associated with positive or negative documents. Here's a
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| quick example of how that can look at runtime.
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+aside("What's Keras?")
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| #[+a("https://keras.io/") Keras] gives you a high-level, declarative
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| interface to define neural networks. Models are trained using Google's
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| #[+a("https://www.tensorflow.org") TensorFlow] by default.
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| #[+a("http://deeplearning.net/software/theano/") Theano] is also
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| supported.
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+code("Runtime usage").
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def count_entity_sentiment(nlp, texts):
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'''Compute the net document sentiment for each entity in the texts.'''
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entity_sentiments = collections.Counter(float)
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for doc in nlp.pipe(texts, batch_size=1000, n_threads=4):
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for ent in doc.ents:
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entity_sentiments[ent.text] += doc.sentiment
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return entity_sentiments
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def load_nlp(lstm_path, lang_id='en'):
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def create_pipeline(nlp):
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return [nlp.tagger, nlp.entity, SentimentAnalyser.load(lstm_path, nlp)]
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return spacy.load(lang_id, create_pipeline=create_pipeline)
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p
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| All you have to do is pass a #[code create_pipeline] callback function
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| to #[code spacy.load()]. The function should take a
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| #[code spacy.language.Language] object as its only argument, and return
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| a sequence of callables. Each callable should accept a
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| #[+api("docs") #[code Doc]] object, modify it in place, and return
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| #[code None].
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p
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| Of course, operating on single documents is inefficient, especially for
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| deep learning models. Usually we want to annotate many texts, and we
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| want to process them in parallel. You should therefore ensure that your
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| model component also supports a #[code .pipe()] method. The
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| #[code .pipe()] method should be a well-behaved generator function that
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| operates on arbitrarily large sequences. It should consume a small
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| buffer of documents, work on them in parallel, and yield them one-by-one.
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+code("Custom Annotator Class").
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class SentimentAnalyser(object):
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@classmethod
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def load(cls, path, nlp):
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with (path / 'config.json').open() as file_:
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model = model_from_json(file_.read())
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with (path / 'model').open('rb') as file_:
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lstm_weights = pickle.load(file_)
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embeddings = get_embeddings(nlp.vocab)
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model.set_weights([embeddings] + lstm_weights)
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return cls(model)
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def __init__(self, model):
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self._model = model
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def __call__(self, doc):
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X = get_features([doc], self.max_length)
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y = self._model.predict(X)
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self.set_sentiment(doc, y)
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def pipe(self, docs, batch_size=1000, n_threads=2):
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for minibatch in cytoolz.partition_all(batch_size, docs):
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Xs = get_features(minibatch)
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ys = self._model.predict(Xs)
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for i, doc in enumerate(minibatch):
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doc.sentiment = ys[i]
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def set_sentiment(self, doc, y):
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doc.sentiment = float(y[0])
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# Sentiment has a native slot for a single float.
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# For arbitrary data storage, there's:
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# doc.user_data['my_data'] = y
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def get_features(docs, max_length):
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Xs = numpy.zeros((len(docs), max_length), dtype='int32')
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for i, doc in enumerate(minibatch):
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for j, token in enumerate(doc[:max_length]):
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Xs[i, j] = token.rank if token.has_vector else 0
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return Xs
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p
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| By default, spaCy 1.0 downloads and uses the 300-dimensional
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| #[+a("http://nlp.stanford.edu/projects/glove/") GloVe] common crawl
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| vectors. It's also easy to replace these vectors with ones you've
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| trained yourself, or to disable the word vectors entirely. If you've
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| installed your word vectors into spaCy's #[+api("vocab") #[code Vocab]]
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| object, here's how to use them in a Keras model:
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+code("Training with Keras").
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def train(train_texts, train_labels, dev_texts, dev_labels,
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lstm_shape, lstm_settings, lstm_optimizer, batch_size=100, nb_epoch=5):
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nlp = spacy.load('en', parser=False, tagger=False, entity=False)
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embeddings = get_embeddings(nlp.vocab)
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model = compile_lstm(embeddings, lstm_shape, lstm_settings)
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train_X = get_features(nlp.pipe(train_texts))
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dev_X = get_features(nlp.pipe(dev_texts))
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model.fit(train_X, train_labels, validation_data=(dev_X, dev_labels),
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nb_epoch=nb_epoch, batch_size=batch_size)
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return model
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def compile_lstm(embeddings, shape, settings):
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model = Sequential()
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model.add(
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Embedding(
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embeddings.shape[1],
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embeddings.shape[0],
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input_length=shape['max_length'],
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trainable=False,
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weights=[embeddings]
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)
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)
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model.add(Bidirectional(LSTM(shape['nr_hidden'])))
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model.add(Dropout(settings['dropout']))
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model.add(Dense(shape['nr_class'], activation='sigmoid'))
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model.compile(optimizer=Adam(lr=settings['lr']), loss='binary_crossentropy',
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metrics=['accuracy'])
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return model
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def get_embeddings(vocab):
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max_rank = max(lex.rank for lex in vocab if lex.has_vector)
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vectors = numpy.ndarray((max_rank+1, vocab.vectors_length), dtype='float32')
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for lex in vocab:
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if lex.has_vector:
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vectors[lex.rank] = lex.vector
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return vectors
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def get_features(docs, max_length):
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Xs = numpy.zeros(len(list(docs)), max_length, dtype='int32')
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for i, doc in enumerate(docs):
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for j, token in enumerate(doc[:max_length]):
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Xs[i, j] = token.rank if token.has_vector else 0
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return Xs
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p
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| For most applications, I recommend using pre-trained word embeddings
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| without "fine-tuning". This means that you'll use the same embeddings
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| across different models, and avoid learning adjustments to them on your
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| training data. The embeddings table is large, and the values provided by
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| the pre-trained vectors are already pretty good. Fine-tuning the
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| embeddings table is therefore a waste of your "parameter budget". It's
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| usually better to make your network larger some other way, e.g. by
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| adding another LSTM layer, using attention mechanism, using character
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| features, etc.
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+h(2, "attribute-hooks") Attribute hooks (experimental)
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p
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| Earlier, we saw how to store data in the new generic #[code user_data]
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| dict. This generalises well, but it's not terribly satisfying. Ideally,
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| we want to let the custom data drive more "native" behaviours. For
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| instance, consider the #[code .similarity()] methods provided by spaCy's
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| #[+api("doc") #[code Doc]], #[+api("token") #[code Token]] and
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| #[+api("span") #[code Span]] objects:
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+code("Polymorphic similarity example").
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span.similarity(doc)
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token.similarity(span)
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doc1.similarity(doc2)
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p
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| By default, this just averages the vectors for each document, and
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| computes their cosine. Obviously, spaCy should make it easy for you to
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| install your own similarity model. This introduces a tricky design
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| challenge. The current solution is to add three more dicts to the
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| #[code Doc] object:
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+aside("Implementation note")
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| The hooks live on the #[code Doc] object because the #[code Span] and
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| #[code Token] objects are created lazily, and don't own any data. They
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| just proxy to their parent #[code Doc]. This turns out to be convenient
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| here — we only have to worry about installing hooks in one place.
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+table(["Name", "Description"])
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+row
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+cell #[code user_hooks]
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+cell Customise behaviour of #[code doc.vector], #[code doc.has_vector], #[code doc.vector_norm] or #[code doc.sents]
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+row
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+cell #[code user_token_hooks]
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+cell Customise behaviour of #[code token.similarity], #[code token.vector], #[code token.has_vector], #[code token.vector_norm] or #[code token.conjuncts]
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+row
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+cell #[code user_span_hooks]
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+cell Customise behaviour of #[code span.similarity], #[code span.vector], #[code span.has_vector], #[code span.vector_norm] or #[code span.root]
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p
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| To sum up, here's an example of hooking in custom #[code .similarity()]
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| methods:
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+code("Add custom similarity hooks").
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class SimilarityModel(object):
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def __init__(self, model):
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self._model = model
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def __call__(self, doc):
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doc.user_hooks['similarity'] = self.similarity
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doc.user_span_hooks['similarity'] = self.similarity
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doc.user_token_hooks['similarity'] = self.similarity
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def similarity(self, obj1, obj2):
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y = self._model([obj1.vector, obj2.vector])
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return float(y[0])
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