"erlarge" a numpy-matrix to numpy-array

[scidam]

So, you have two matrices of shape nxm and want to concatenate them by third axis and get one matrix of shape nxmx2.
Thats easy:

import numpy as np
A = np.random.rand(10, 20)
B = np.random.rand(10, 20)
C = np.dstack([A, B])
print(C.shape)