Checkerboard Permutation

permuteeven.py

import numpy as np
from itertools import permutations

foo = np.arange(25).reshape(5,5)

def permuteevens(A):
    mask = np.fromfunction(lambda i,j: (i+j)%2==0, A.shape )
    vals = A[mask]
    for p in permutations(vals):
        A[mask] = p
        yield A