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| import tensorflow as tf from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("MNIST_data", one_hot=True)
INPUT_NODE = 784 OUTPUT_NODE = 10
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
def inference(input_tensor, avg_class, weights1, biases1, weights2, biases2): if avg_class is 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)
x = tf.placeholder(tf.float32, [None, INPUT_NODE]) y_ = tf.placeholder(tf.float32, [None, OUTPUT_NODE])
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
learnging_rate = tf.train.exponential_decay( LEARNING_RATE_BASE, global_step, mnist.train.num_examples / BATCH_SIZE, LEARNING_RATE_DECAY)
train_step = tf.train.GradientDescentOptimizer(learnging_rate).minimize(loss, global_step=global_step)
with tf.control_dependencies([train_step, variables_averages_op]): train_op = tf.no_op()
correct_prediction = tf.equal(tf.argmax(average_y, 1), tf.argmax(y_, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
if __name__ == "__main__": 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 "训练轮数:", i, ",准确率:", validate_acc * 100, "%" 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 "训练轮数:", TRAINING_STEPS, ",准确率:", test_acc * 100, "%"
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