Simple question about Genetic Algorithm and Direct Search toolbox

Hello.I have a simple question to ask.I tried the example from Matlab regarding about the rastriginsfcn.m.The problem is I did'nt get the same answer as what the Matlab guide has shown?What is wrong wit it?Is it true that i will keep getting different values?

Answer 1

[Sandy Patel]

There is nothing wrong with it. Yes, ga uses a stochastic search method so it is not uncommon to get different results that satisfies the tolerance condition. A good check is to run the search a few times and see if the results is wildly different. Since it is random, if it returns to the same fit result, then it is a good sign that you got the minimum. Always be careful that you are not just in a local minimum and that the search was just not robust enough.

[Hazem]

So how can one check that he is not in local minimum ? and his search is robust enough?