#第一部分,前向传播
import tensorflow as tf
#定义神经网络结构相关的参数
INPUT_NODE = 784
OUTPUT_NODE = 10
LAYER1_NODE = 500
#通过tf.get_Variable函数来获取变量。在训练神经网络时会创建这些变量;在测试时会通过
#保存的模型加载这些变量的取值。而且更加方便的是,因为可以在变量加载时将滑动平均变量
#重命名,所以可以直接通过同样的名字在训练时使用变量自身,而在测试时使用变量的滑动平均
#值。在这个函数中也会将变量的正则化损失加入损失集合。
def get_weight_variable(shape, regularizer):
weights = tf.get_variable(
"weights", shape,
initializer=tf.truncated_normal_initializer(stddev=0.1))
if regularizer != None:
tf.add_to_collection(\'losses\', regularizer(weights))
return weights
#定义神经网络的前向传播过程。
def inference(input_tensor, regularizer):
#第一层
with tf.variable_scope(\'layer1\'):
#tf.get_variable/tf.Variable都可以,但是假如多次调用要留意reuse = True
weights = get_weight_variable(
[INPUT_NODE, LAYER1_NODE], regularizer)
biases = tf.get_variable(
"biases", [LAYER1_NODE],
initializer = tf.constant_initializer(0.0))
layer1 = tf.nn.relu(tf.matmul(input_tensor, weights) + biases)
#第二层
with tf.variable_scope(\'layer2\'):
weights = get_weight_variable(
[LAYER1_NODE, OUTPUT_NODE], regularizer)
biases = tf.get_variable(
"biases", [OUTPUT_NODE],
initializer = tf.constant_initializer(0.0))
layer2 = tf.matmul(layer1, weights) + biases
return layer2
#训练部分
import os
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
import mnist_inference
BATCH_SIZE = 100
LEARNING_RATE_BASE = 0.8
LEARNING_RATE_DECAY = 0.99
REGULARAZTION_RATE = 0.0001
TRAINING_STEPS = 30000
MOVING_AVERAGE_DECAY = 0.99
# 模型保存的路径和文件名。
MODEL_SAVE_PATH = "saves_model_path"
MODEL_NAME = "model.ckpt"
def train(mnist):
#定义输入输出placeholder。
x = tf.placeholder(
tf.float32, [None, mnist_inference.INPUT_NODE], name=\'x-input\')
y_= tf.placeholder(
tf.float32, [None, mnist_inference.OUTPUT_NODE], name=\'y-input\')
regularizer = tf.contrib.layers.l2_regularizer(REGULARAZTION_RATE)
#inference函数
y = mnist_inference.inference(x, regularizer)
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())
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)
loss = cross_entropy_mean + tf.add_n(tf.get_collection(\'losses\'))
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\')
saver = tf.train.Saver()
with tf.Session() as sess:
tf.global_variables_initializer().run()
for i in range(TRAINING_STEPS):
xs, ys = mnist.train.next_batch(BATCH_SIZE)
_, loss_value, step = sess.run([train_op, loss, global_step],
feed_dict={x:xs, y_:ys})
if i % 1000 == 0:
print("After %d training step(s), loss on training "
"batch is %g." % (step, loss_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("/tmp/data", one_hot=True)
train(mnist)
if __name__ == \'__main__\':
tf.app.run()
#评价部分,保存模型
import time
import tensorflow as tf
from tensorflow.examples.tutorials.mnist import input_data
import mnist_inference
import mnist_train
# 每10秒加载一次最新的模型,并在测试数据上测试最新模型的正确率
EVAL_INTERVAL_SECS = 10
def evaluate(mnist):
with tf.Graph().as_default() as g:
# 定义输入输出的格式
x = tf.placeholder(
tf.float32, [None, mnist_inference.INPUT_NODE], name=\'x-input\')
y_= tf.placeholder(
tf.float32, [None, mnist_inference.OUTPUT_NODE],name=\'y-input\')
validate_feed = {x: mnist.validation.images,
y_:mnist.validation.labels}
# 用封装好的函数来计算结果,不关注正则化损失的值
y = mnist_inference.inference(x, None)
correct_prediction = tf.equal(tf.argmax(y, 1), tf.argmax(y_, 1))
accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))
variable_averages = tf.train.ExponentialMovingAverage(
mnist_train.MOVING_AVERAGE_DECAY)
variables_to_restore = variable_averages.variables_to_restore()
saver = tf.train.Saver(variables_to_restore)
while True:
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=validate_feed)
print("After %s training step(s), validation "
"accuracy = %g" % (global_step, accuracy_score))
else:
print(\'No checkpoint file found\')
return
time.sleep(EVAL_INTERVAL_SECS)
def main(argv=None):
mnist = input_data.read_data_sets("/tmp/data", one_hot=True)
evaluate(mnist)
if __name__ == \'__main__\':
tf.app.run()