Single optima instead of non-dominated solutions

[rabiu42000]

What causes multi or many objectives to return a single optima instead of non-dominated solutions? I am getting a single optima when i use NSGAII or NSGAII for a 3-objective optimization.

[blankjul]

If you have no constraints then the most likely reason is that your objectives are simply not conflicting (there exists one solution dominating all others).

[rabiu42000]

I have constraints in the optimization problem.

[blankjul]

if no feasible solution can be found, the least feasible solution might be returned (this option needs to be activated though).

[rabiu42000]

I have that option activated. All constraint are not violated. It returns a result but was expecting more than one (non-dominated solutions) because is multi-objective.

[blankjul]

then, I my best guess is that either the constraints cause a diversity loss, or your objective are not conflicting.

[rabiu42000]

I think that should solve my problem. I will take a look into my objectives again. Thank you very much.