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Francois Chollet 2016-08-13 11:54:04 -07:00
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'''This example demonstrates the use of fasttext for text classification
Based on Joulin et al's paper:
Bags of Tricks for Efficient Text Classification
https://arxiv.org/abs/1607.01759
Can achieve accuracy around 88% after 5 epochs in 70s.
'''
from __future__ import print_function
import numpy as np
np.random.seed(1337) # for reproducibility
from keras.preprocessing import sequence
from keras.models import Sequential
from keras.layers import Dense, Flatten
from keras.layers import Embedding
from keras.layers import AveragePooling1D
from keras.datasets import imdb
# set parameters:
max_features = 20000
maxlen = 400
batch_size = 32
embedding_dims = 20
nb_epoch = 5
print('Loading data...')
(X_train, y_train), (X_test, y_test) = imdb.load_data(nb_words=max_features)
print(len(X_train), 'train sequences')
print(len(X_test), 'test sequences')
print('Pad sequences (samples x time)')
X_train = sequence.pad_sequences(X_train, maxlen=maxlen)
X_test = sequence.pad_sequences(X_test, maxlen=maxlen)
print('X_train shape:', X_train.shape)
print('X_test shape:', X_test.shape)
print('Build model...')
model = Sequential()
# we start off with an efficient embedding layer which maps
# our vocab indices into embedding_dims dimensions
model.add(Embedding(max_features,
embedding_dims,
input_length=maxlen))
# we add a AveragePooling1D, which will average the embeddings
# of all words in the document
model.add(AveragePooling1D(pool_length=model.output_shape[1]))
# We flatten the output of the AveragePooling1D layer
model.add(Flatten())
# We project onto a single unit output layer, and squash it with a sigmoid:
model.add(Dense(1, activation='sigmoid'))
model.compile(loss='binary_crossentropy',
optimizer='adam',
metrics=['accuracy'])
model.fit(X_train, y_train,
batch_size=batch_size,
nb_epoch=nb_epoch,
validation_data=(X_test, y_test))