I am using genetic algorithm optimization toolbox. i have done evrything i am also getting output and all. but i want is i want the output in particular range.

For example

function t=compST(input)
x(1) = input(1);
x(2) = input(2)
x(3) = input(3)
x(4) = input(4)
x(5) = input(5)
t = 122.14-0.84.*x(1)-0.42.*x(2)+0.34.*x(3)-0.09.*x(4)+363.77.*x(5);
output = [t]

here t is compressive strenth . i want the t in range of 40-80 MPA range how can i do that

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/gads/custom-output-function-for-genetic-algorithm.html

If you are using ga() then the above link shows you how to halt if the function value is within a specified value.

[harsh Brar]

thank you response.

but i am having difficulty interpreting the said code. can you tell me if there's any simpler way. and also i am looking to get output in range only not less than or greater than something.

thank you

[Walter Roberson]

options = optimoptions('ga', 'OutputFcn', @stop40_60, 'MaxGenerations', 1e5);
A = []; b = []; Aeq = []; beq = []; lb = []; ub = []; nonlcon = [];
[bestx, tval] = ga(@compST, 5,  A, b, Aeq, beq, lb, ub, nonlcon, options);

Optimization terminated: range statisfied

display(bestx)

bestx = 1×5

2.4174 -3.7488 4.7636 8.8115 -0.2069

display(tval)

tval = 47.2493

function t=compST(x)
    t = 122.14-0.84.*x(1)-0.42.*x(2)+0.34.*x(3)-0.09.*x(4)+363.77.*x(5);
end

function [state,options,optchanged] = stop40_60(options,state,flag)
    optchanged = false;
    switch flag
        case 'init'
        case 'iter'
            % Find the best objective function, and stop if it is right range
            mask = state.Score >= 40 & state.Score <= 60;
            if any(mask)
                state.StopFlag = 'range statisfied';
                state.Score = state.Score(mask);
                state.Population = state.Population(mask,:);
                state.Best(end) = state.Score(end);
            end
        case 'done'
    end
end

[Walter Roberson]

options = optimoptions('ga', 'FitnessLimit', 400, 'MaxGenerations', 1e5);
A = []; b = []; Aeq = []; beq = []; lb = []; ub = []; nonlcon = [];
obj = @(x) (compST(x)-60).^2;
bestx = ga(obj, 5,  A, b, Aeq, beq, lb, ub, nonlcon, options);

Optimization terminated: minimum fitness limit reached.

display(bestx)

bestx = 1×5

-7.4205 -9.9567 3.9257 7.0063 -0.2431

display(compST(bestx))

   44.8276

function t=compST(x)
    t = 122.14-0.84.*x(1)-0.42.*x(2)+0.34.*x(3)-0.09.*x(4)+363.77.*x(5);
end

[harsh Brar]

i wanna thank you wholeheartedly. i am absolute beginner in matlab. i have been spinning my mind around this for a while now. thank you.