48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
'''Train a Bidirectional LSTM on the IMDB sentiment classification task.
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Output after 4 epochs on CPU: ~0.8146
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Time per epoch on CPU (Core i7): ~150s.
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'''
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from __future__ import print_function
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import numpy as np
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np.random.seed(1337) # for reproducibility
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from keras.preprocessing import sequence
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from keras.models import Sequential
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from keras.layers import Dense, Dropout, Embedding, LSTM, Bidirectional
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from keras.datasets import imdb
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max_features = 20000
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maxlen = 100 # cut texts after this number of words (among top max_features most common words)
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batch_size = 32
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print('Loading data...')
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(X_train, y_train), (X_test, y_test) = imdb.load_data(nb_words=max_features)
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print(len(X_train), 'train sequences')
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print(len(X_test), 'test sequences')
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print("Pad sequences (samples x time)")
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X_train = sequence.pad_sequences(X_train, maxlen=maxlen)
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X_test = sequence.pad_sequences(X_test, maxlen=maxlen)
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print('X_train shape:', X_train.shape)
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print('X_test shape:', X_test.shape)
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y_train = np.array(y_train)
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y_test = np.array(y_test)
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model = Sequential()
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model.add(Embedding(max_features, 128, input_length=maxlen))
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model.add(Bidirectional(LSTM(64)))
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model.add(Dropout(0.5))
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model.add(Dense(1, activation='sigmoid'))
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# try using different optimizers and different optimizer configs
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model.compile('adam', 'binary_crossentropy', metrics=['accuracy'])
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print('Train...')
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model.fit(X_train, y_train,
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batch_size=batch_size,
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nb_epoch=4,
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validation_data=[X_test, y_test])
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