Python - Matrix outer product

Question

Given two matrices

A: m * r
B: n * r

I want to generate another matrix C: m * n, with each entry C_ij being a mat

Answer 1

Use numpy;

In [1]: import numpy as np

In [2]: A = np.array([[1, 2], [3, 4]])

In [3]: B = np.array([[3, 1], [1, 2]])

In [4]: C = np.outer(A, B)

In [5]: C
Out[5]: 
array([[ 3,  1,  1,  2],
       [ 6,  2,  2,  4],
       [ 9,  3,  3,  6],
       [12,  4,  4,  8]])

Once you have the desired result, you can use numpy.reshape() to mold it in almost any shape you want;

In [6]: C.reshape([4,2,2])
Out[6]: 
array([[[ 3,  1],
        [ 1,  2]],

       [[ 6,  2],
        [ 2,  4]],

       [[ 9,  3],
        [ 3,  6]],

       [[12,  4],
        [ 4,  8]]])