吴恩达《神经网络与深度学习》神经网络基础之逻辑回归

image.png
image.png
image.png
image.png
image.png
image.png
image.png
image.png
image.png
image.png
image.png

算法流程：
J=0;dw1=0;dw2=0;db=0;
for i = 1 to m
z(i) = wx(i)+b;
a(i) = sigmoid(z(i));
J += -[y(i)log(a(i))+(1-y(i)）log(1-a(i));
dz(i) = a(i)-y(i);
dw1 += x1(i)dz(i);
dw2 += x2(i)dz(i);
db += dz(i);
J/= m;
dw1/= m;
dw2/= m;
db/= m;
w=w-alphadw
b=b-alphadb