Indices of fixed size sub-matrices of numpy array

Question

I am implementing an algorithm which requires me to look at non-overlapping consecutive submatrices within a (strictly two dimensional) numpy array. eg, for the 12 by 12

Answer 1

You can use the one-liner:

r = 3
c = 3
lenr = a.shape[0]/r
lenc = a.shape[1]/c
np.array([a[i*r:(i+1)*r,j*c:(j+1)*c] for (i,j) in np.ndindex(lenr,lenc)]).reshape(lenr,lenc,r,c)