Crossover operators (which take two parent chromosomes and combine them to produce a child) need to be carefully designed in order to guarantee that the number of ones and
zero’s (i.e., the number of stocks) in the children chromosomes does not change.
To deal with this constraint, we tried two different crossover operators. First, a two-point ‘orderbased’ crossover [28] has been used.
The idea behind the order-based crossover is to swap the genes in the order found
at the other parent, going from left to right.
The number of ones and zeros will automatically remain the same.