I have a problem which I am trying to solve with genetic algorithms. The problem is selecting some subset (say 4) of 100 integers (these integers are just ids that represent something else). Order does not matter, the solution to the problem is a SET of integers not an ordered list. I have a good fitness function but am having trouble with the crossover function.
I want to be able to mate the following two chromosomes:
[1 2 3 4] and [3 4 5 6] into something useful. Clearly I cannot use the typical crossover function because I could end up with duplicates in my children which would represent invalid solutions. What is the best crossover method in this case.
Just ignore any element that occurs in both of the sets (i.e. in their intersection.), that is leave such elements unchanged in both sets.
The rest of the elements form two disjoint sets, to which you can apply pretty much any random transformation (e.g. swapping some pairs randomly) without getting duplicates.
This can be thought of as ordering and aligning both sets so that matching elements face each other and applying one of the standard crossover algorithms.