hadamardNANI.py

from numpy import ones, any, eye
from random import randint

def attemptHadamard(mat):
        mat[randint(0, 667)][randint(0, 667)] *= -1
        if checkHadamard(mat):
                print('Success!\n', mat)
                return True
        else:
                return False

def checkHadamard(mat):
        return not (mat.transpose() @ mat - 668 * eye(668)).any()

mat = ones([668, 668])

while not attemptHadamard(mat):
        pass

while True:
        pass