2.神经网络的编程基础补充

1.数组乘积

a = np.random.randn(4, 3) # a.shape = (4, 3)

b = np.random.randn(3, 2) # b.shape = (3, 2)

c = a * b

Answer:维度不同数组无法相乘

2.矩阵乘积

a = np.random.randn(12288, 150) # a.shape = (12288, 150)

b = np.random.randn(150, 45) # b.shape = (150, 45)

c = np.dot(a, b)

3.广播总结

4.矩阵&列向量声明

x = img.reshape((32 * 32 * 3, 1))    3027*1的列向量