crossover.py

def mate(self, partner):
    """
    Create offspring with a order-crossover method
    :param partner: a second p1 which will participate in the mating
    :return: two new offspring individuals
    """
    c1, c2 = np.zeros((2, self.n_pieces), dtype=int)
    start, end = np.sort(np.random.choice(range(self.n_pieces), 2, replace=False))

    p1 = self.chromosome
    p2 = partner.chromosome

    c1[start:end + 1] = p1[start:end + 1]
    mask1 = ~np.in1d(p1, p1[start:end + 1])
    mask2 = ~np.in1d(p2, p1[start:end + 1])
    c1[mask1] = p2[mask2]

    c2[start:end + 1] = p2[start:end + 1]
    mask1 = ~np.in1d(p2, p2[start:end + 1])
    mask2 = ~np.in1d(p1, p2[start:end + 1])
    c2[mask1] = p1[mask2]

    return Individual(self.polygons, self.board_size, c1), Individual(self.polygons, self.board_size, c2)