用Tensorflow实现多层神经网络
 1 import tensorflow as tf
 2 import numpy as np
 3 def addLayer(inputData,inSize,outSize,activity_function = None):
 4 Weights = tf.Variable(tf.random_normal([inSize,outSize]))
 5 basis = tf.Variable(tf.zeros([1,outSize])+0.1)
 6 weights_plus_b = tf.matmul(inputData,Weights)+basis
 7 if activity_function is None:
 8 ans = weights_plus_b
 9 else:
10 ans = activity_function(weights_plus_b)
11 return ans
12 x_data = np.linspace(-1,1,300)[:,np.newaxis] # 转为列向量
13 noise = np.random.normal(0,0.05,x_data.shape)
14 y_data = np.square(x_data)+0.5+noise
15 xs = tf.placeholder(tf.float32,[None,1]) # 样本数未知,特征数为1,占位符最后要以字典形式在运行中填入
16 ys = tf.placeholder(tf.float32,[None,1])
17 l1 = addLayer(xs,1,10,activity_function=tf.nn.relu) # relu是激励函数的一种
18 l2 = addLayer(l1,10,1,activity_function=None)
19 loss = tf.reduce_mean(tf.reduce_sum(tf.square((ys-l2)),reduction_indices = [1]))#需要向相加索引号,redeuc执行跨纬度操作
20 train = tf.train.GradientDescentOptimizer(0.1).minimize(loss) # 选择梯度下降法
21 init = tf.initialize_all_variables()
22 sess = tf.Session()
23 sess.run(init)
24 for i in range(10000):
25 sess.run(train,feed_dict={xs:x_data,ys:y_data})
26 if i%50 == 0:
27 print sess.run(loss,feed_dict={xs:x_data,ys:y_data})
28
 另一种实现https://www.cnblogs.com/cloud-ken/p/8436436.html
posted on 2018-08-24 11:49  西沟冯衙内  阅读(144)  评论(0编辑  收藏  举报