How does genetic algorithm derive the best fitness and average fitness values for each generation?

My Matlab version is R2021a. The help give the sample function is

[x,fval,exitflag,output,population,scores] = ga(___)

The output parameters do not have fitness for each generation.

It gives the fitness in figure, but I want know the values.

Answer 1

[Sam Chak]

Hi @Time N

The output here in the "Output Argument", only gives basic information about the optimization process returned as a structure.

If you want to evaluate the fitness for each generation, then you must call the OutputFcn through specifying it the option

option = optimoptions('ga', 'OutputFcn', @gaoutfun)
[x, fval, exitflag, output] = ga(fun, nvars, A, b, Aeq, beq, lb, ub, nonlcon, options)

and then create the ga output function that must have the following calling syntax:

function [state, options, optchanged] = gaoutfun(options, state, flag)
    % See example here:
    % https://www.mathworks.com/help/gads/custom-output-function-for-genetic-algorithm.html
end

You have a lot of options to choose from the state structure for ga information about the current generation. Click here to see:

https://www.mathworks.com/help/gads/genetic-algorithm-options.html#f20829

[Time N]

Thanks for your solution. It is helpful.

[Sam Chak]

You're welcome, @Time N. Good to know that it helps.