如上图所示的两层神经网络,
单样本向量化: 多样本向量化:
for i=1 to 4:
z= Wx+ b Z = W X+ b
(4,1) (4,3) (3,1) (4,1) (4,4) (4,3) (3,4) (4,4)
a=sigmoid( z) A = sigmoid( Z )
(4,1) (4,1) (4,4) (4,4)
z= W a + b Z = WA + b
(1,1) (1,4) (4,1) (1,1) (1,4) (1,4) (4,4) [1,4]
a=sigmoid( z) A = sigmoid( Z )
(1,1) (1,1) (1,4) (1,4)