1、函数

函数：f(z) = 1 / (1 + exp( − z))

导数：f(z)' = f(z)(1 − f(z))

2、tensorflow实现

#!/usr/bin/env python# -*- coding: utf-8 -*-import tensorflow as tfinput_data = tf.Variable( [[0, 10, -10],[1,2,3]] , dtype = tf.float32 )output = tf.nn.sigmoid(input_data)with tf.Session() as sess:    init = tf.initialize_all_variables()    sess.run(init)    print(sess.run(output))

　　输出为：

[[ 5.00000000e-01 9.99954581e-01 4.53978719e-05]

[ 7.31058598e-01 8.80797029e-01 9.52574134e-01]]