用tensorflow实现J(w)=w**2-10*w+25的微分结果
import numpy as np
import tensorflow as tf
w=tf.Variable(0,dtype=tf.float32)
cost=tf.add(tf.add(w**2,tf.multiply(-10,w)),25)
train=tf.train.GradiantDescentOptimizer(0.01).minimize(cost)
init=tf.global_variables_initializer()
session=tf.Session()
session.run(init)
print(session.run(w))
session.run(train)
print(session.run(w))
for i in range(1000):
session.run(train)
print(session.run(w))
