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	The sentences of test data in sentence entailment example should be generated with integers limited to vocab_size.
		
			
				
	
	
		
			269 lines
		
	
	
		
			9.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			269 lines
		
	
	
		
			9.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
| # Semantic similarity with decomposable attention (using spaCy and Keras)
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| # Practical state-of-the-art text similarity with spaCy and Keras
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| import numpy
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| 
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| from keras.layers import InputSpec, Layer, Input, Dense, merge
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| from keras.layers import Lambda, Activation, Dropout, Embedding, TimeDistributed
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| from keras.layers import Bidirectional, GRU, LSTM
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| from keras.layers.noise import GaussianNoise
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| from keras.layers.advanced_activations import ELU
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| import keras.backend as K
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| from keras.models import Sequential, Model, model_from_json
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| from keras.regularizers import l2
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| from keras.optimizers import Adam
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| from keras.layers.normalization import BatchNormalization
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| from keras.layers.pooling import GlobalAveragePooling1D, GlobalMaxPooling1D
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| from keras.layers import Merge
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| 
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| 
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| def build_model(vectors, shape, settings):
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|     '''Compile the model.'''
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|     max_length, nr_hidden, nr_class = shape
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|     # Declare inputs.
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|     ids1 = Input(shape=(max_length,), dtype='int32', name='words1')
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|     ids2 = Input(shape=(max_length,), dtype='int32', name='words2')
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| 
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|     # Construct operations, which we'll chain together.
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|     embed = _StaticEmbedding(vectors, max_length, nr_hidden, dropout=0.2, nr_tune=5000)
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|     if settings['gru_encode']:
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|         encode = _BiRNNEncoding(max_length, nr_hidden, dropout=settings['dropout'])
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|     attend = _Attention(max_length, nr_hidden, dropout=settings['dropout'])
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|     align = _SoftAlignment(max_length, nr_hidden)
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|     compare = _Comparison(max_length, nr_hidden, dropout=settings['dropout'])
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|     entail = _Entailment(nr_hidden, nr_class, dropout=settings['dropout'])
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| 
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|     # Declare the model as a computational graph.
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|     sent1 = embed(ids1) # Shape: (i, n)
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|     sent2 = embed(ids2) # Shape: (j, n)
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| 
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|     if settings['gru_encode']:
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|         sent1 = encode(sent1)
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|         sent2 = encode(sent2)
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| 
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|     attention = attend(sent1, sent2)  # Shape: (i, j)
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| 
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|     align1 = align(sent2, attention)
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|     align2 = align(sent1, attention, transpose=True)
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| 
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|     feats1 = compare(sent1, align1)
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|     feats2 = compare(sent2, align2)
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| 
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|     scores = entail(feats1, feats2)
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| 
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|     # Now that we have the input/output, we can construct the Model object...
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|     model = Model(input=[ids1, ids2], output=[scores])
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| 
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|     # ...Compile it...
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|     model.compile(
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|         optimizer=Adam(lr=settings['lr']),
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|         loss='categorical_crossentropy',
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|         metrics=['accuracy'])
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|     # ...And return it for training.
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|     return model
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| 
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| 
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| class _StaticEmbedding(object):
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|     def __init__(self, vectors, max_length, nr_out, nr_tune=1000, dropout=0.0):
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|         self.nr_out = nr_out
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|         self.max_length = max_length
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|         self.embed = Embedding(
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|                         vectors.shape[0],
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|                         vectors.shape[1],
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|                         input_length=max_length,
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|                         weights=[vectors],
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|                         name='embed',
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|                         trainable=False)
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|         self.tune = Embedding(
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|                         nr_tune,
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|                         nr_out,
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|                         input_length=max_length,
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|                         weights=None,
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|                         name='tune',
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|                         trainable=True,
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|                         dropout=dropout)
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|         self.mod_ids = Lambda(lambda sent: sent % (nr_tune-1)+1,
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|                               output_shape=(self.max_length,))
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| 
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|         self.project = TimeDistributed(
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|                             Dense(
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|                                 nr_out,
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|                                 activation=None,
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|                                 bias=False,
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|                                 name='project'))
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| 
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|     def __call__(self, sentence):
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|         def get_output_shape(shapes):
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|             print(shapes)
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|             return shapes[0]
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|         mod_sent = self.mod_ids(sentence)
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|         tuning = self.tune(mod_sent)
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|         #tuning = merge([tuning, mod_sent],
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|         #    mode=lambda AB: AB[0] * (K.clip(K.cast(AB[1], 'float32'), 0, 1)),
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|         #    output_shape=(self.max_length, self.nr_out))
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|         pretrained = self.project(self.embed(sentence))
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|         vectors = merge([pretrained, tuning], mode='sum')
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|         return vectors
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| 
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| 
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| class _BiRNNEncoding(object):
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|     def __init__(self, max_length, nr_out, dropout=0.0):
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|         self.model = Sequential()
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|         self.model.add(Bidirectional(LSTM(nr_out, return_sequences=True,
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|                                          dropout_W=dropout, dropout_U=dropout),
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|                                          input_shape=(max_length, nr_out)))
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|         self.model.add(TimeDistributed(Dense(nr_out, activation='relu', init='he_normal')))
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|         self.model.add(TimeDistributed(Dropout(0.2)))
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| 
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|     def __call__(self, sentence):
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|         return self.model(sentence)
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| 
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| 
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| class _Attention(object):
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|     def __init__(self, max_length, nr_hidden, dropout=0.0, L2=0.0, activation='relu'):
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|         self.max_length = max_length
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|         self.model = Sequential()
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|         self.model.add(Dropout(dropout, input_shape=(nr_hidden,)))
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|         self.model.add(
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|             Dense(nr_hidden, name='attend1',
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|                 init='he_normal', W_regularizer=l2(L2),
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|                 input_shape=(nr_hidden,), activation='relu'))
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|         self.model.add(Dropout(dropout))
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|         self.model.add(Dense(nr_hidden, name='attend2',
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|             init='he_normal', W_regularizer=l2(L2), activation='relu'))
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|         self.model = TimeDistributed(self.model)
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| 
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|     def __call__(self, sent1, sent2):
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|         def _outer(AB):
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|             att_ji = K.batch_dot(AB[1], K.permute_dimensions(AB[0], (0, 2, 1)))
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|             return K.permute_dimensions(att_ji,(0, 2, 1))
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|         return merge(
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|                 [self.model(sent1), self.model(sent2)],
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|                 mode=_outer,
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|                 output_shape=(self.max_length, self.max_length))
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| 
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| 
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| class _SoftAlignment(object):
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|     def __init__(self, max_length, nr_hidden):
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|         self.max_length = max_length
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|         self.nr_hidden = nr_hidden
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| 
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|     def __call__(self, sentence, attention, transpose=False):
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|         def _normalize_attention(attmat):
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|             att = attmat[0]
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|             mat = attmat[1]
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|             if transpose:
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|                 att = K.permute_dimensions(att,(0, 2, 1))
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|             # 3d softmax
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|             e = K.exp(att - K.max(att, axis=-1, keepdims=True))
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|             s = K.sum(e, axis=-1, keepdims=True)
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|             sm_att = e / s
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|             return K.batch_dot(sm_att, mat)
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|         return merge([attention, sentence], mode=_normalize_attention,
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|                       output_shape=(self.max_length, self.nr_hidden)) # Shape: (i, n)
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| 
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| 
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| class _Comparison(object):
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|     def __init__(self, words, nr_hidden, L2=0.0, dropout=0.0):
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|         self.words = words
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|         self.model = Sequential()
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|         self.model.add(Dropout(dropout, input_shape=(nr_hidden*2,)))
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|         self.model.add(Dense(nr_hidden, name='compare1',
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|             init='he_normal', W_regularizer=l2(L2)))
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|         self.model.add(Activation('relu'))
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|         self.model.add(Dropout(dropout))
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|         self.model.add(Dense(nr_hidden, name='compare2',
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|                         W_regularizer=l2(L2), init='he_normal'))
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|         self.model.add(Activation('relu'))
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|         self.model = TimeDistributed(self.model)
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| 
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|     def __call__(self, sent, align, **kwargs):
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|         result = self.model(merge([sent, align], mode='concat')) # Shape: (i, n)
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|         avged = GlobalAveragePooling1D()(result, mask=self.words)
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|         maxed = GlobalMaxPooling1D()(result, mask=self.words)
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|         merged = merge([avged, maxed])
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|         result = BatchNormalization()(merged)
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|         return result
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| 
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| 
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| class _Entailment(object):
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|     def __init__(self, nr_hidden, nr_out, dropout=0.0, L2=0.0):
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|         self.model = Sequential()
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|         self.model.add(Dropout(dropout, input_shape=(nr_hidden*2,)))
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|         self.model.add(Dense(nr_hidden, name='entail1',
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|             init='he_normal', W_regularizer=l2(L2)))
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|         self.model.add(Activation('relu'))
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|         self.model.add(Dropout(dropout))
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|         self.model.add(Dense(nr_hidden, name='entail2',
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|             init='he_normal', W_regularizer=l2(L2)))
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|         self.model.add(Activation('relu'))
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|         self.model.add(Dense(nr_out, name='entail_out', activation='softmax',
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|                         W_regularizer=l2(L2), init='zero'))
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| 
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|     def __call__(self, feats1, feats2):
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|         features = merge([feats1, feats2], mode='concat')
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|         return self.model(features)
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| 
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| 
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| class _GlobalSumPooling1D(Layer):
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|     '''Global sum pooling operation for temporal data.
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| 
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|     # Input shape
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|         3D tensor with shape: `(samples, steps, features)`.
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| 
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|     # Output shape
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|         2D tensor with shape: `(samples, features)`.
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|     '''
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|     def __init__(self, **kwargs):
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|         super(_GlobalSumPooling1D, self).__init__(**kwargs)
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|         self.input_spec = [InputSpec(ndim=3)]
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| 
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|     def get_output_shape_for(self, input_shape):
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|         return (input_shape[0], input_shape[2])
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| 
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|     def call(self, x, mask=None):
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|         if mask is not None:
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|             return K.sum(x * K.clip(mask, 0, 1), axis=1)
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|         else:
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|             return K.sum(x, axis=1)
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| 
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| 
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| def test_build_model():
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|     vectors = numpy.ndarray((100, 8), dtype='float32')
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|     shape = (10, 16, 3)
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|     settings = {'lr': 0.001, 'dropout': 0.2, 'gru_encode':True}
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|     model = build_model(vectors, shape, settings)
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| 
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| 
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| def test_fit_model():
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| 
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|     def _generate_X(nr_example, length, nr_vector):
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|         X1 = numpy.ndarray((nr_example, length), dtype='int32')
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|         X1 *= X1 < nr_vector
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|         X1 *= 0 <= X1
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|         X2 = numpy.ndarray((nr_example, length), dtype='int32')
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|         X2 *= X2 < nr_vector
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|         X2 *= 0 <= X2
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|         return [X1, X2]
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| 
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|     def _generate_Y(nr_example, nr_class):
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|         ys = numpy.zeros((nr_example, nr_class), dtype='int32')
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|         for i in range(nr_example):
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|             ys[i, i % nr_class] = 1
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|         return ys
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| 
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|     vectors = numpy.ndarray((100, 8), dtype='float32')
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|     shape = (10, 16, 3)
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|     settings = {'lr': 0.001, 'dropout': 0.2, 'gru_encode':True}
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|     model = build_model(vectors, shape, settings)
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| 
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|     train_X = _generate_X(20, shape[0], vectors.shape[0])
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|     train_Y = _generate_Y(20, shape[2])
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|     dev_X = _generate_X(15, shape[0], vectors.shape[0])
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|     dev_Y = _generate_Y(15, shape[2])
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| 
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|     model.fit(train_X, train_Y, validation_data=(dev_X, dev_Y), nb_epoch=5,
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|               batch_size=4)
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| 
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| 
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| __all__ = [build_model]
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