前向传播过程mnist_inference.py
import tensorflow as tf
# 定义神经网络相关的参数
INPUT_NODE = 784
OUTPUT_NODE = 10
def inference(inputs, dropout_keep_prob):
x_image = tf.reshape(inputs, [-1, 28, 28, 1])
# 第一层:卷积层
conv1_weights = tf.get_variable("conv1_weights", [5, 5, 1, 32], initializer=tf.truncated_normal_initializer(stddev=0.1)) # 过滤器大小为5*5, 当前层深度为1, 过滤器的深度为32
conv1 = tf.nn.conv2d(x_image, filter=conv1_weights, strides=[1, 1, 1, 1], padding='SAME') # 移动步长为1, 使用全0填充
conv1_biases = tf.get_variable("conv1_biases", [32], initializer=tf.constant_initializer(0.0))
relu1 = tf.nn.relu(tf.nn.bias_add(conv1, conv1_biases)) # 激活函数Relu去线性化
# 第二层:最大池化层
# 池化层过滤器的大小为2*2, 移动步长为2,使用全0填充
pool1 = tf.nn.max_pool(relu1, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME') #输出14*14*32
# 第三层:卷积层
conv2_weights = tf.get_variable("conv2_weights", [5, 5, 32, 64], initializer=tf.truncated_normal_initializer(stddev=0.1)) # 过滤器大小为5*5, 当前层深度为32, 过滤器的深度为64
conv2 = tf.nn.conv2d(pool1, conv2_weights, strides=[1, 1, 1, 1], padding='SAME') # 移动步长为1, 使用全0填充
conv2_biases = tf.get_variable("conv2_biases", [64], initializer=tf.constant_initializer(0.0))
relu2 = tf.nn.relu(tf.nn.bias_add(conv2, conv2_biases))
# 第四层:最大池化层
# 池化层过滤器的大小为2*2, 移动步长为2,使用全0填充
pool2 = tf.nn.max_pool(relu2, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding='SAME') #输出7*7*64
# 第五层:全连接层
pool2_vector = tf.reshape(pool2, [-1, 7 * 7 * 64])
fc1_weights = tf.get_variable("fc1_weights", [7 * 7 * 64, 1024], initializer=tf.truncated_normal_initializer(stddev=0.1)) # 7*7*64=3136把前一层的输出变成特征向量
fc1_baises = tf.get_variable("fc1_baises", [1024], initializer=tf.constant_initializer(0.1))
fc1 = tf.nn.relu(tf.matmul(pool2_vector, fc1_weights) + fc1_baises)
# 为了减少过拟合,加入Dropout层
fc1_dropout = tf.nn.dropout(fc1, dropout_keep_prob)
# 第六层:全连接层
fc2_weights = tf.get_variable("fc2_weights", [1024, 10], initializer=tf.truncated_normal_initializer(stddev=0.1)) # 神经元节点数1024, 分类节点10
fc2_biases = tf.get_variable("fc2_biases", [10], initializer=tf.constant_initializer(0.1))
fc2 = tf.matmul(fc1_dropout, fc2_weights) + fc2_biases
return fc2
训练mnist_train.py
import os
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
import mnist_inference
#
BATCH_SIZE = 100
#学习率
LEARN_RATE = 0.001
MODEL_SAVE_PATH = "model/"
MODEL_NAME = "model.ckpt"
EPOCH = 2
def train(mnist):
inputs = tf.placeholder(tf.float32, [None, mnist_inference.INPUT_NODE])
labels = tf.placeholder(tf.float32, [None, mnist_inference.OUTPUT_NODE])
dropout_keep_prob = tf.placeholder(tf.float32)
logits = mnist_inference.inference(inputs, dropout_keep_prob)
global_step = tf.Variable(0, trainable=False)
cross_entropy = tf.nn.softmax_cross_entropy_with_logits(logits=logits, labels=labels)
#tf.nn.sparse_softmax_cross_entropy_with_logits
cost = tf.reduce_mean(cross_entropy)
train_op = tf.train.AdamOptimizer(LEARN_RATE).minimize(cost, global_step=global_step)
saver = tf.train.Saver()
with tf.Session() as sess:
tf.global_variables_initializer().run()
print(mnist.train.images.shape)
for i in range(20000):
batch_inputs, batch_labels = mnist.train.next_batch(BATCH_SIZE)
_, cost_value, step = sess.run([train_op, cost, global_step], feed_dict={inputs: batch_inputs, labels: batch_labels, dropout_keep_prob:0.5})
if i % 1000 == 0:
print("After %d training step(s), loss on training batch is %f." % (step, cost_value))
saver.save(sess, os.path.join(MODEL_SAVE_PATH, MODEL_NAME), global_step=global_step)
def main(argv=None):
mnist = input_data.read_data_sets("MNIST_data/", one_hot=True)
train(mnist)
if __name__ == '__main__':
tf.app.run()
评估mnis_eval.py
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
import mnist_inference
import mnist_train
def evaluate(mnist):
inputs = tf.placeholder(tf.float32, [None, 784])
labels = tf.placeholder(tf.float32, [None, 10])
dropout_keep_prob = tf.placeholder(tf.float32)
logits = mnist_inference.inference(inputs, dropout_keep_prob)
print(logits)
correct_prediction = tf.equal(tf.argmax(logits, 1), tf.argmax(labels, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
saver = tf.train.Saver()
with tf.Session() as sess:
ckpt = tf.train.get_checkpoint_state(mnist_train.MODEL_SAVE_PATH)
if ckpt and ckpt.model_checkpoint_path:
saver.restore(sess, ckpt.model_checkpoint_path)
global_step = ckpt.model_checkpoint_path.split('/')[-1].split('-')[-1]
accuracy_score = sess.run(accuracy, feed_dict={inputs: mnist.test.images, labels: mnist.test.labels, dropout_keep_prob:1.0})
print("After %s training step(s), validation accuracy = %f" % (global_step, accuracy_score))
else:
print("No checkpoint file found")
return
def main(argv=None):
mnist = input_data.read_data_sets("MNIST_data/", one_hot=True)
evaluate(mnist)
if __name__ == '__main__':
tf.app.run()