multi objective optimization - metric of quality

[MichaelRara]

Hi,
what metric is used to decide what solution in multi objective optimization is better?
How do you compare them?
https://pygad.readthedocs.io/en/latest/pygad_more.html#multi-objective-optimization

[ahmedfgad]

Hi @MichaelRara,

For multi-objective optimization, there are 2 special parent selectors:

1. nsga2: This selects the parents based on non-dominated sorting and crowding distance.
2. tournament_nsga2: This selects the parents using tournament selection which uses non-dominated sorting and crowding distance to rank the solutions.

So, simply the metrics are non-dominated sorting and crowding distance.