How to write selection function in genetic algorithm(Global Optimization Toolbox: ga)

Hey guys, I have some problems to use customized genetic algorithm. Any help would be appreciated.

I want to use customized selection function. My code is below, but I receive error message: Index exceeds matrix dimensions.

Example function used is y=3*(1-x(1)).^2.*exp(-(x(1).^2)-(x(2)+1).^2)-10*(x(1)/5-x(1).^3-x(2).^5).*exp(-x(1).^2-x(2).^2)-1/3*exp(-(x(1)+1).^2-x(2).^2).

Please check my code and tell me what is the problem.

Thank you.