numpy实现两层layer

暑期第二天回顾两层网络训练细节，对应CS231n-class-10，练习numpy写layer

import numpy as np

x = np.array([[0, 0, 1], [0, 1, 1], [1, 0, 1], [1, 1, 1]])
y = np.array([[0, 1, 1, 0]]).T
print(x)
print(y)

w0 = 2*np.random.random((3, 4)) - 1
w1 = 2*np.random.random((4, 1)) - 1

for j in range(60000):
    l1 = 1 / (1 + np.exp(-(np.dot(x, w0))))
    l2 = 1 / (1 + np.exp(-(np.dot(l1, w1))))
    l2_delta = (y-l2)*(l2*(1-l2))
    l1_delta = l2_delta.dot(w1.T) * (l1*(1-l1))
    w1 += l1.T.dot(l2_delta)
    w0 += x.T.dot(l1_delta)
    loss=y-l2
    if(j%10000==0):
        print(loss)
print(l2)