Why does the F function require 100 samples of the same value?

[cyasing]

I have a problem with 1 variable (with proper bounds) and 3 objectives (need to think of what constraints the problem should have). When declaring out["F""], it asks for a shape of (100,3). I simply multiplied the values of F with an array of 100 ones, and ran it. The problem does run, but it does not generate a pareto front with NSGA-II, simply returning a singular point (same as when I used 2 objectives). What can I do about it?

Essentially, the problem is defined from a physics model, and I need to optimize some of its output variables. I notice that there are a few "ideal" runs, but still the singular point output graph.

[cyasing]

Okay, I got it was due to population size. Sorry!