import math
import numpy as np
from pymoo.model.crossover import Crossover
from pymoo.operators.crossover.util import crossover_mask
class HalfUniformCrossover(Crossover):
def __init__(self, prob_hux=0.5, **kwargs):
super().__init__(2, 2, **kwargs)
self.prob_hux = prob_hux
def _do(self, problem, X, **kwargs):
_, n_matings, n_var = X.shape
# the mask do to the crossover
M = np.full((n_matings, n_var), False)
not_equal = X[0] != X[1]
# create for each individual the crossover range
for i in range(n_matings):
I = np.where(not_equal[i])[0]
n = math.ceil(len(I) / 2)
if n > 0:
_I = I[np.random.permutation(len(I))[:n]]
M[i, _I] = True
_X = crossover_mask(X, M)
return _X
