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genetic-algorithmcrossover

select same parents in multiple Tournament selection

I'm wondering if I can select two same parents in two iteration of selection in a genetic algorithm (in a same population with tournament selection).

Can I?

Solution

  • A lot of these decisions are made after experimentation with one's particular software and domain.

    Of course two parents can generate more than two children. This may happen either because:

    • crossover operator creates more than two children;
    • tournament selection picks repeatedly the same parents (with a simple steady state population this is a common event).

    Generally it's not recommended to create too many individuals with the same parents because you could have a too "restricted trend" (what "too many" means is debatable).

    So you can often find some form of prevention. Apart from checking explicitly for the "same parents" occurrence, there are other techniques.

    E.g.

    • demetic grouping the same parents can generate a numerous offspring but children will compete among them.

    • family competition replacement schemes are different way of limiting the amounts of multiple crossovers with the same parents.

    • ...