import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
INPUT_NODE = 784
OUTPUT_NODE = 10
#配置参数
LAYER1_NODE = 500
BATCH_SIZE = 100
LEARNING_RATE_BASE = 0.8
LEARNING_RATE_DECAY = 0.99
REGULARIZATION_RATE = 0.0001
TRAINING_STEPS = 30000
MOVING_AVERAGE_DECAY = 0.99
#辅助函数
def inference(input_tensor, avg_class, weights1,biases1,weights2,biases2):
if avg_class == None:
layer1 = tf.nn.relu(tf.matmul(input_tensor,weights1)+biases1)
return tf.matmul(layer1,weights2)+biases2
else:
layer1 = tf.nn.relu(tf.matmul(input_tensor, avg_class.average(weights1)) + avg_class.average(biases1))
return tf.matmul(layer1, avg_class.average(weights2)) + avg_class.average(biases2)
#训练过程
def train(mnist):
x = tf.placeholder(tf.float32, [None, INPUT_NODE], name='x-input')
y_ = tf.placeholder(tf.float32, [None,OUTPUT_NODE], name = 'y-input')
weights1 = tf.Variable(tf.truncated_normal([INPUT_NODE,LAYER1_NODE], stddev=0.1))
biases1 = tf.Variable(tf.constant(0.1, shape=[LAYER1_NODE]))
weights2 = tf.Variable(tf.truncated_normal([LAYER1_NODE,OUTPUT_NODE], stddev=0.1))
biases2 = tf.Variable(tf.constant(0.1,shape=[OUTPUT_NODE]))
y = inference(x,None,weights1, biases1, weights2, biases2)
global_step = tf.Variable(0, trainable = False)
variable_averages = tf.train.ExponentialMovingAverage( MOVING_AVERAGE_DECAY, global_step)
variables_averages_op = variable_averages.apply( tf.trainable_variables())
average_y = inference( x, variable_averages, weights1,biases1,weights2,biases2)
cross_entropy = tf.nn.sparse_softmax_cross_entropy_with_logits( logits=y,labels=tf.argmax(y_,1))
cross_entropy_mean = tf.reduce_mean(cross_entropy)
regularizer = tf.contrib.layers.l2_regularizer(REGULARIZATION_RATE)
regularization = regularizer(weights1) + regularizer(weights2)
loss = cross_entropy_mean + regularization
learning_rate = tf.train.exponential_decay(LEARNING_RATE_BASE,global_step,mnist.train.num_examples / BATCH_SIZE, LEARNING_RATE_DECAY)
train_step = tf.train.GradientDescentOptimizer(learning_rate).minimize( loss,global_step= global_step)
with tf.control_dependencies([train_step ,variables_averages_op]):
train_op = tf.no_op(name='train')
correct_prediction = tf.equal(tf.argmax(average_y,1), tf.argmax(y_,1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction,tf.float32))
#初始化会话并开始训练过程
with tf.Session() as sess:
tf.global_variables_initializer().run()
validate_feed = {x:mnist.validation.images, y_:mnist.validation.labels}
test_feed = {x:mnist.test.images, y_:mnist.test.labels}
for i in range(TRAINING_STEPS):
if i % 1000 == 0:
validate_acc = sess.run(accuracy, feed_dict=validate_feed)
print('after %d training steps, validation accuracy ''using average model is %g' % (i,validate_acc))
xs,ys = mnist.train.next_batch(BATCH_SIZE)
sess.run(train_op,feed_dict = {x: xs , y_: ys})
test_acc = sess.run(accuracy, feed_dict = test_feed)
print('after %d training step,test accuracy using average''model is %g' % ( TRAINING_STEPS,test_acc))
def main(argv=None):
mnist = input_data.read_data_sets('./tmp/data',one_hot=True)
train(mnist)
if __name__ == '__main__':
tf.app.run()
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