How to multiply two matrices with different size using python?

Question

I'm trying to multiply two matrices that has different size.

import numpy as np

a = np.random.randn(4, 3)
b = np.random.randn(4, 1)

print a
print b

How should I multiply a and b so that the multipled matrix's size is 4*3?

I want to multiply matrix 'b' to each row of matrix 'a'.
So that if matrix a is
[[1, 2, 3],
[2, 3, 4]]
and b is
[[2],
[3]]
a*b is
[[2, 4, 6],
[4, 6 ,8]]

Plz help me, if possible, plz use numpy

Answer 1

You don't need to do anything special.

> import numpy as np
> a = np.array([[1,2,3],[2,3,4]])
> b = np.array([[2], [3]])
> a
array([[1, 2, 3],
 [2, 3, 4]])
> b
array([[2],
 [3]])
> a * b
array([[ 2, 4, 6],
 [ 6, 9, 12]])

I'm assuming this is actually the output you want.