Updating x in fitness function

For a custom vectorised fitness function like this,

FitnessFunction = @(x) my_fitness(x,a,b);

I need to modify the values of x (i.e 'This population')based on some parameters computed in the fitness function. I have tried including the code for this in the fitness function but I guess this is not the right way. In the subsequent steps, while generating the next generation, ga is using the same x values as before and not the modified ones. Can these values be modified within the fitness function?

Answer 1

[Walter Roberson]

ga is the wrong approach for that. In ga, you never modify the population in the objective function. Instead, you generate a fitness value for the population as-is. Then the population along with all of the fitness values are passed to the crossover or mutation functions, which can generate whatever modified values desired.

To phrase this a different way, take that detection and modification code out of the fitness function and put it in the crossover or mutation function.