TensorFlow经典案例6：深度学习前传多层感知机

经典案例多层感知机
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
mnist = input_data.read_data_sets("/tmp/data/",one_hot= True)

learning_rate = 0.001
training_epochs = 15
batch_size = 100
display_step = 1

n_hidden_1 = 256 #第一层神经元的个数
n_hidden_2 = 256 #第二层神经元的个数
n_input = 784
n_classes = 10   #分类的个数

x = tf.placeholder("float",[None,784])
y = tf.placeholder("float",[None,n_classes])

#创建神经网络结构
def multilayer_perceptron(x,weights,biases):
    layer_1 = tf.add(tf.matmul(x,weights['h1']),biases['b1'])
    layer_1 = tf.nn.relu(layer_1)

    layer_2 = tf.add(tf.matmul(layer_1,weights['h2']),biases['b2'])
    layer_2 = tf.nn.relu(layer_2)

    out_layer = tf.matmul(layer_2,weights['out']) + biases['out']
    return out_layer

weigths = {
    'h1': tf.Variable(tf.random_normal([n_input,n_hidden_1])),
    'h2': tf.Variable(tf.random_normal([n_hidden_1,n_hidden_2])),
    'out': tf.Variable(tf.random_normal([n_hidden_2,n_classes]))
}

biases = {
    'b1': tf.Variable(tf.random_normal([n_hidden_1])),
    'b2': tf.Variable(tf.random_normal([n_hidden_2])),
    'out': tf.Variable(tf.random_normal([n_classes]))
}

pred = multilayer_perceptron(x,weigths,biases)

cost = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits=pred,labels=y))
train_step = tf.train.GradientDescentOptimizer(learning_rate).minimize(cost)

init = tf.global_variables_initializer()

with tf.Session() as sess:
    sess.run(init)
    for epoch in range(training_epochs):
        avg_cost = 0.
        total_batch = int(mnist.train.num_examples / batch_size)
        for i in range(total_batch):
            batch_x,batch_y = mnist.train.next_batch(batch_size)
            _,c = sess.run([train_step,cost],feed_dict={x:batch_x,y:batch_y})
            avg_cost += c/total_batch
        if epoch % display_step == 0:
            print("Epoch:",'%04d' % (epoch+1),"cost=","{:.9f}".format(avg_cost))
    print("训练完毕")
    correct_prediction = tf.equal(tf.argmax(pred,1),tf.argmax(y,1))
    accuracy = tf.reduce_mean(tf.cast(correct_prediction,"float"))
    print("Accuracy：",accuracy.eval({x:mnist.test.images,y:mnist.test.labels}))