堆叠稀疏自编码器SSAE的python代码编写,数据集使用minist手写体识别
时间: 2024-06-10 13:10:49 浏览: 234
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以下是堆叠稀疏自编码器(SSAE)的Python代码,使用MNIST手写数字数据集:
```
import tensorflow as tf
import numpy as np
import matplotlib.pyplot as plt
from tensorflow.examples.tutorials.mnist import input_data
# 加载MNIST数据集
mnist = input_data.read_data_sets('MNIST_data', one_hot=True)
# 定义超参数
learning_rate = 0.01
training_epochs = 20
batch_size = 256
display_step = 1
# 定义输入大小
n_input = 784
# 定义隐藏层大小
n_hidden_1 = 256
n_hidden_2 = 128
n_hidden_3 = 64
# 定义占位符
X = tf.placeholder("float", [None, n_input])
# 定义权重和偏置项
weights = {
'encoder_h1': tf.Variable(tf.random_normal([n_input, n_hidden_1])),
'encoder_h2': tf.Variable(tf.random_normal([n_hidden_1, n_hidden_2])),
'encoder_h3': tf.Variable(tf.random_normal([n_hidden_2, n_hidden_3])),
'decoder_h1': tf.Variable(tf.random_normal([n_hidden_3, n_hidden_2])),
'decoder_h2': tf.Variable(tf.random_normal([n_hidden_2, n_hidden_1])),
'decoder_h3': tf.Variable(tf.random_normal([n_hidden_1, n_input])),
}
biases = {
'encoder_b1': tf.Variable(tf.random_normal([n_hidden_1])),
'encoder_b2': tf.Variable(tf.random_normal([n_hidden_2])),
'encoder_b3': tf.Variable(tf.random_normal([n_hidden_3])),
'decoder_b1': tf.Variable(tf.random_normal([n_hidden_2])),
'decoder_b2': tf.Variable(tf.random_normal([n_hidden_1])),
'decoder_b3': tf.Variable(tf.random_normal([n_input])),
}
# 定义编码器
def encoder(x):
layer_1 = tf.nn.sigmoid(tf.add(tf.matmul(x, weights['encoder_h1']), biases['encoder_b1']))
layer_2 = tf.nn.sigmoid(tf.add(tf.matmul(layer_1, weights['encoder_h2']), biases['encoder_b2']))
layer_3 = tf.nn.sigmoid(tf.add(tf.matmul(layer_2, weights['encoder_h3']), biases['encoder_b3']))
return layer_3
# 定义解码器
def decoder(x):
layer_1 = tf.nn.sigmoid(tf.add(tf.matmul(x, weights['decoder_h1']), biases['decoder_b1']))
layer_2 = tf.nn.sigmoid(tf.add(tf.matmul(layer_1, weights['decoder_h2']), biases['decoder_b2']))
layer_3 = tf.nn.sigmoid(tf.add(tf.matmul(layer_2, weights['decoder_h3']), biases['decoder_b3']))
return layer_3
# 构建模型
encoder_op = encoder(X)
decoder_op = decoder(encoder_op)
# 定义损失函数和优化器
cost = tf.reduce_mean(tf.pow(X - decoder_op, 2))
optimizer = tf.train.RMSPropOptimizer(learning_rate).minimize(cost)
# 初始化变量
init = tf.global_variables_initializer()
# 运行图
with tf.Session() as sess:
sess.run(init)
total_batch = int(mnist.train.num_examples/batch_size)
# 开始训练
for epoch in range(training_epochs):
# 遍历所有批次
for i in range(total_batch):
batch_xs, batch_ys = mnist.train.next_batch(batch_size)
# 运行优化器
_, c = sess.run([optimizer, cost], feed_dict={X: batch_xs})
# 显示训练日志
if epoch % display_step == 0:
print("Epoch:", '%04d' % (epoch+1), "cost=", "{:.9f}".format(c))
print("Optimization Finished!")
# 测试模型
encode_decode = sess.run(
decoder_op, feed_dict={X: mnist.test.images[:10]})
# 显示重构结果
f, a = plt.subplots(2, 10, figsize=(10, 2))
for i in range(10):
a[0][i].imshow(np.reshape(mnist.test.images[i], (28, 28)))
a[1][i].imshow(np.reshape(encode_decode[i], (28, 28)))
plt.show()
```
这段代码实现了一个三层的堆叠稀疏自编码器(SSAE),使用MNIST手写数字数据集进行训练和测试。在训练过程中,使用RMSProp优化器和均方误差损失函数来训练模型。最后,测试模型,并展示重构结果。
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