Make special diagonal matrix in Numpy

Question

I am trying to make a numpy array that looks like this:

[a b c       ]
[  a b c     ]
[    a b c   ]
[      a b c ] 

So this involves updat

Answer 1

Using my answer to this question: changing the values of the diagonal of a matrix in numpy , you can do some tricky slicing to get a view of each diagonal, then do the assignment. In this case it would just be:

import numpy as np
A = np.zeros((4,6))
# main diagonal
A.flat[:A.shape[1]**2:A.shape[1]+1] = a
# first superdiagonal
A.flat[1:max(0,A.shape[1]-1)*A.shape[1]:A.shape[1]+1] = b
# second superdiagonal
A.flat[2:max(0,A.shape[1]-2)*A.shape[1]:A.shape[1]+1] = c