Minimise a fitness function using GA toolbox having variable number of variables
1 view (last 30 days)
Show older comments
Rakesh Jain
on 11 Feb 2017
Commented: Walter Roberson
on 11 Feb 2017
I have an error function which I wish to minimise using GA. The error function can be a function of 1,2, 3 or many variables depending on the input given by the user. How should I write a fitness function for the GA toolbox? For example, if we have to minimise y which is a function of x, we create a separate matlab file with the command function y = abc(x) and use it in the GA toolbox. But in my case, the number of variables itself is not fixed. So how should I write such a fitness function ?
0 Comments
Accepted Answer
Walter Roberson
on 11 Feb 2017
ga() always minimizes a function of one variable -- but the variable is permitted to be a vector.
For example,
F = @(x) (sum( (-x).^(0:length(x)-1) ) - 10000).^2
nvar = input('Number of variables?');
opts = optimoptions('ga', 'PlotFcn', @gaplotbestf, 'MaxGenerations', 1800);
[best_x, fval] = ga(F, nvar, [], [], [], [], [], [], [], opts)
(2 is the most interesting number of variables for the above)
2 Comments
Walter Roberson
on 11 Feb 2017
You could try
opts = optimoptions(@ga, 'PlotFcn', @gaplotbestf, 'MaxGenerations', 1800);
but I suspect that you might not have the Global Optimization Toolbox installed (or licensed perhaps) and so do not have ga. Try
which ga
to see.
More Answers (0)
See Also
Categories
Find more on Introduction to Installation and Licensing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!