Genetic Algorithm OPTIMTOOL Error

Hi All,

I am running GA problem via OPTIMTOOL. This is my defined parameters at OPTIMTOOL

 Fitness Function:@myff
 Number of variables :4
 Lower Bound: [1 14 30 12]
 Upper Bond : [2 22 60 16]

And @myff code is per below :

function TotalDelay=myff(C,g,x,c)

        a=(1-(g/C))^2; 
        p=1-((g/C)*x);
        d1i=(0.38*C*a)/p;

        a2=173*(x^2);
        ri1=sqrt( (x-1) + (x-1)^2 + ((16*x)/c) );

        d2i=a2*ri1;

        TotalDelay=(d1i+d2i);

end;

When start the solver the below error pops out : "Input argument "g" is undefined."

Can anyone enlighten me, where did i made a mistakes.

Thanking in advance. Dawood

Answer 1

[Steven Lord]

From the documentation for the ga function:

"The fitness function should accept a row vector of length nvars and return a scalar value."

Your function, as defined, requires a row vector of length nvars and other information. For that scenario, see this suggestion in the Tips section on that documentation page:

"To write a function with additional parameters to the independent variables that can be called by ga, see Passing Extra Parameters (Optimization Toolbox)."

You will need to use one of the techniques on the Passing Extra Parameters page to pass additional inputs to your fitness function. The easiest will probably be the anonymous function approach.

[Alan Weiss]

It is possible that your variables C, g, x, and c are all scalars that you want to optimize. In that case, instead of following Steve's suggestion, you would write your objective (fitness) function like this:

function TotalDelay = myff(r)
C = r(1);
g = r(2);
x = r(3);
c = r(4);
a=(1-(g/C))^2; % etc., put the rest of your code here

See Compute Objective Functions.

P.S. For such a smooth objective function, I suggest that you NOT use ga, but instead use a more appropriate solver such as fminunc or fmincon.

Alan Weiss

MATLAB mathematical toolbox documentation

Answer 2

[Shaik Dawood Hussain]

Thanks very much guys.

The code is working.

tq

[Mohammed Bakr]

hi

i have the same problem now can you tell me what can i do