numpy：向量x矩阵x向量乘法

Question

How can I multiply the multiple vectors and matrix in numpy shown in example below:

# 1. vector
a = np.array([1, 2])
# matrix
b = np.array([[4, 0],[0, 5]])
# 2. vector
c = a.T

I want to multiply axbxc and find the 24 as a result.

Answer 1

Use numpy.matmul(a, b) as follows:

import numpy as np
# 1. vector
a = np.array([1, 2])
# matrix
b = np.array([[4, 0],[0, 5]])
# 2. vector
c = a.T
# np.matmul gets 2 inputs which are matrix (1x2, 2x3 etc.) and returns result.
result = np.matmul(np.matmul(a,b), c)

print(result)
# 24