Passing extra input parameters for creation function in ga

How to add an extra input parameter to the creation function in genetic algorithm tool. I have read the documentation on passing extra parameters but couldn't get how to implement it in this case since the creation function must have the following calling syntax :

    function Population = myfun(GenomeLength, FitnessFcn, options)

Answer 1

[Adam]

I don't really know enough about the GA process in Matlab, but generally speaking, what you have is a function of 3 variables, but you can also 'bake in' any other parameters you want at function creation time e.g.

f = @(x,y,z) x^2 + y^2 + z^2

is a function of 3 arguments with calling syntax

res = f(x,y,z);

e.g.

res = f( 2, 3, 4 );

i.e. similar to what you need to have.

But the following also has the same calling syntax:

a = 6;
b = 7;

g = @(x,y,z) x^2 + y^2 + z^2 + a + b;

res = g(x,y,z);

e.g.

res = g( 2, 3, 4 );

So with function handle like this you can turn a function of e.g. 5 arguments into a function of 3 arguments by binding (to use a C++ and maybe other languages term) the other 2 arguments in at the time you create the function handle.

Here a and b must be known (as shown) at function creation time, x, y and z only need to be known at call time.

Coming back to your case this means that as long as you have those 3 input arguments in that list of variable arguments you can bind in whatever other arguments you want e.g.

a = 7;
b = 8;
f = @( GenomeLength, FitnessFcn, options) myfun(GenomeLength, FitnessFcn, options, a, b);

Then you can pass f in as your creation function, from my understanding of what is being asked for.

[Hari]

This is showing an error:

    Error: "f" was previously used as a variable, conflicting with its use here as the name of a function or command.

[Adam]

Well, obviously I just used 'f' as an example. You can use whatever name you want and should use something more meaningful

[Hari]

I don't think it was problem with the name specified to the variable because it showed error when I tried with other names too.

[Adam]

It gave an error that f was used as a variable even when you named it something else?

[Hari]

No, it changed with the variable name I gave. I solved the problem. Declaring the variable as global and then using it in the function