Function generate_sudoku

DemoPrograms/Demo_Sudoku.py:22–50

Create a Sukoku board :param mask_rate: % of squares to hide :type mask_rate: float :rtype: List[numpy.ndarry, numpy.ndarry]

(mask_rate)

def generate_sudoku(mask_rate):
    """
    Create a Sukoku board

    :param mask_rate: % of squares to hide
    :type mask_rate: float
    :rtype: List[numpy.ndarry, numpy.ndarry]
    """
    while True:
        n = 9
        solution = np.zeros((n, n), np.int)
        rg = np.arange(1, n + 1)
        solution[0, :] = np.random.choice(rg, n, replace=False)
        try:
            for r in range(1, n):
                for c in range(n):
                    col_rest = np.setdiff1d(rg, solution[:r, c])
                    row_rest = np.setdiff1d(rg, solution[r, :c])
                    avb1 = np.intersect1d(col_rest, row_rest)
                    sub_r, sub_c = r//3, c//3
                    avb2 = np.setdiff1d(np.arange(0, n+1), solution[sub_r*3:(sub_r+1)*3, sub_c*3:(sub_c+1)*3].ravel())
                    avb = np.intersect1d(avb1, avb2)
                    solution[r, c] = np.random.choice(avb, size=1)
            break
        except ValueError:
            pass
    puzzle = solution.copy()
    puzzle[np.random.choice([True, False], size=solution.shape, p=[mask_rate, 1 - mask_rate])] = 0
    return puzzle, solution