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# Copyright 2016 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import os
import numpy as np
from sklearn import metrics
import pandas
import tensorflow as tf
from tensorflow.contrib import learn
### Training data
# Downloads, unpacks and reads DBpedia dataset.
dbpedia = learn.datasets.load_dataset('dbpedia')
X_train, y_train = pandas.DataFrame(dbpedia.train.data)[1], pandas.Series(dbpedia.train.target)
X_test, y_test = pandas.DataFrame(dbpedia.test.data)[1], pandas.Series(dbpedia.test.target)
### Process vocabulary
MAX_DOCUMENT_LENGTH = 10
vocab_processor = learn.preprocessing.VocabularyProcessor(MAX_DOCUMENT_LENGTH)
X_train = np.array(list(vocab_processor.fit_transform(X_train)))
X_test = np.array(list(vocab_processor.transform(X_test)))
n_words = len(vocab_processor.vocabulary_)
print('Total words: %d' % n_words)
### Models
EMBEDDING_SIZE = 50
def average_model(X, y):
word_vectors = learn.ops.categorical_variable(X, n_classes=n_words,
embedding_size=EMBEDDING_SIZE, name='words')
features = tf.reduce_max(word_vectors, reduction_indices=1)
return learn.models.logistic_regression(features, y)
def rnn_model(X, y):
"""Recurrent neural network model to predict from sequence of words
to a class."""
# Convert indexes of words into embeddings.
# This creates embeddings matrix of [n_words, EMBEDDING_SIZE] and then
# maps word indexes of the sequence into [batch_size, sequence_length,
# EMBEDDING_SIZE].
word_vectors = learn.ops.categorical_variable(X, n_classes=n_words,
embedding_size=EMBEDDING_SIZE, name='words')
# Split into list of embedding per word, while removing doc length dim.
# word_list results to be a list of tensors [batch_size, EMBEDDING_SIZE].
word_list = tf.unpack(word_vectors, axis=1)
# Create a Gated Recurrent Unit cell with hidden size of EMBEDDING_SIZE.
cell = tf.nn.rnn_cell.GRUCell(EMBEDDING_SIZE)
# Create an unrolled Recurrent Neural Networks to length of
# MAX_DOCUMENT_LENGTH and passes word_list as inputs for each unit.
_, encoding = tf.nn.rnn(cell, word_list, dtype=tf.float32)
# Given encoding of RNN, take encoding of last step (e.g hidden size of the
# neural network of last step) and pass it as features for logistic
# regression over output classes.
return learn.models.logistic_regression(encoding, y)
model_path = '/tmp/skflow_examples/text_classification'
if os.path.exists(model_path):
classifier = learn.TensorFlowEstimator.restore(model_path)
else:
classifier = learn.TensorFlowEstimator(model_fn=rnn_model, n_classes=15,
steps=100, optimizer='Adam', learning_rate=0.01, continue_training=True)
# Continuously train for 1000 steps
while True:
try:
classifier.fit(X_train, y_train)
except KeyboardInterrupt:
classifier.save(model_path)
break
# Predict on test set
score = metrics.accuracy_score(y_test, classifier.predict(X_test))
print('Accuracy: {0:f}'.format(score))
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