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

The Einstein notation expresses this problem nicely

In [85]: np.einsum('ac,bd->abcd',A,B)
Out[85]: 
array([[[[ 3,  1],
         [ 6,  2]],

        [[ 1,  2],
         [ 2,  4]]],


       [[[ 9,  3],
         [12,  4]],

        [[ 3,  6],
         [ 4,  8]]]])