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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.
"""This showcases how simple it is to build image classification networks.
It follows description from this TensorFlow tutorial:
https://www.tensorflow.org/versions/master/tutorials/mnist/pros/index.html#deep-mnist-for-experts
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import numpy as np
from sklearn import metrics
import tensorflow as tf
layers = tf.contrib.layers
learn = tf.contrib.learn
def max_pool_2x2(tensor_in):
return tf.nn.max_pool(
tensor_in, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME')
def conv_model(feature, target, mode):
"""2-layer convolution model."""
# Convert the target to a one-hot tensor of shape (batch_size, 10) and
# with a on-value of 1 for each one-hot vector of length 10.
target = tf.one_hot(tf.cast(target, tf.int32), 10, 1, 0)
# Reshape feature to 4d tensor with 2nd and 3rd dimensions being
# image width and height final dimension being the number of color channels.
feature = tf.reshape(feature, [-1, 28, 28, 1])
# First conv layer will compute 32 features for each 5x5 patch
with tf.variable_scope('conv_layer1'):
h_conv1 = layers.convolution(
feature, 32, kernel_size=[5, 5], activation_fn=tf.nn.relu)
h_pool1 = max_pool_2x2(h_conv1)
# Second conv layer will compute 64 features for each 5x5 patch.
with tf.variable_scope('conv_layer2'):
h_conv2 = layers.convolution(
h_pool1, 64, kernel_size=[5, 5], activation_fn=tf.nn.relu)
h_pool2 = max_pool_2x2(h_conv2)
# reshape tensor into a batch of vectors
h_pool2_flat = tf.reshape(h_pool2, [-1, 7 * 7 * 64])
# Densely connected layer with 1024 neurons.
h_fc1 = layers.dropout(
layers.fully_connected(
h_pool2_flat, 1024, activation_fn=tf.nn.relu),
keep_prob=0.5,
is_training=mode == tf.contrib.learn.ModeKeys.TRAIN)
# Compute logits (1 per class) and compute loss.
logits = layers.fully_connected(h_fc1, 10, activation_fn=None)
loss = tf.losses.softmax_cross_entropy(target, logits)
# Create a tensor for training op.
train_op = layers.optimize_loss(
loss,
tf.contrib.framework.get_global_step(),
optimizer='SGD',
learning_rate=0.001)
return tf.argmax(logits, 1), loss, train_op
def main(unused_args):
### Download and load MNIST dataset.
mnist = learn.datasets.load_dataset('mnist')
### Linear classifier.
feature_columns = learn.infer_real_valued_columns_from_input(
mnist.train.images)
classifier = learn.LinearClassifier(
feature_columns=feature_columns, n_classes=10)
classifier.fit(mnist.train.images,
mnist.train.labels.astype(np.int32),
batch_size=100,
steps=1000)
score = metrics.accuracy_score(mnist.test.labels,
list(classifier.predict(mnist.test.images)))
print('Accuracy: {0:f}'.format(score))
### Convolutional network
classifier = learn.Estimator(model_fn=conv_model)
classifier.fit(mnist.train.images,
mnist.train.labels,
batch_size=100,
steps=20000)
score = metrics.accuracy_score(mnist.test.labels,
list(classifier.predict(mnist.test.images)))
print('Accuracy: {0:f}'.format(score))
if __name__ == '__main__':
tf.app.run()
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