Ga does not find the optimal value

Question

Erik Beste 2022-5-4

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https://ww2.mathworks.cn/matlabcentral/answers/1711390-ga-does-not-find-the-optimal-value

评论： Erik Beste 2022-5-5

Hi Matlab comunity after I tried fmincon:

https://ch.mathworks.com/matlabcentral/answers/1707170-fmincon-does-not-fulfil-constraints?s_tid=mlc_ans_email_view#comment_2135955

I now tried ga to solve my problem with integers

x=ga(@(x)fAraucoMarkt(x,AraucoEnergy),4,[],[],[],[],LB,RB,@(x)bedMarkt(x,AraucoEnergy),[2:4]);

I guess it works but I do not get the optimal solution:

x=ga(@(x)fAraucoMarkt(x,AraucoEnergy),4,[],[],[],[],LB,RB,@(x)bedMarkt(x,AraucoEnergy),[2:4]);

Optimization terminated: average change in the penalty fitness value less than options.FunctionTolerance

but constraints are not satisfied.

Is there anyway to get a better solution (I was thinking of random starting numbers and than a list of all found solutions) but as I can not define start point I do not know how to get this.

And while I am at it I had an nonlinear eauqlity constrain which was like this

ceq(1)=Restschuld-0;

I was thinking in changing it to a inequality constrain Restschuld is smaller than 1 and bigger than -1

but I dont know how to do this any idea?

Anyone an Idea

Greetings

Erik

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Walter Roberson 2022-5-4

Restschuld is smaller than 1 and bigger than -1

Those would be bounds constraints, which you would store in LB and RB

Erik Beste 2022-5-4

在 MATLAB Online 中打开

So my conditions are like this

function [c,ceq] = bedMarkt(x,AraucoEnergy)
%UNTITLED5 Summary of this function goes here
%   Detailed explanation goes here
minSpeicher=fminSpeich(x,AraucoEnergy);
Restschuld=fRestschuld(x,AraucoEnergy);
c=0.1-minSpeicher;
ceq=Restschuld-0;
end

I tought that the bound constrains just adress the input parameters

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Answer 1

Walter Roberson 2022-5-4

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You have 3 variables, each of which can only be the integers 2, 3, or 4. That is only 3^3 = 27 possibilities.

Just run all of those possibilities separately, in a loop, with those variables as constants for the duration of the run.

This would have the additional advantage that since you would no longer have integer constraints, you would be able to add your own nonlinear constraint function.

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Erik Beste 2022-5-4

编辑：Erik Beste 2022-5-4

在 MATLAB Online 中打开

Thanks a lot everybody you guys are really helping a lot thanks so much.

So first: I am trying your idea @Alan Weiss :

for i = 0:15
    for j = 1:30
        for k = 0:70
            x=zeros(1,4);
            %Fremdkapitalanteil
            LBFK = LB(1,1);
            RBFK = RB(1,1);
            x(1,1) = (RBFK-LBFK).*rand(1,1) + LBFK;
            x(1,2) = i;
            x(1,3) = j;
            x(1,4) = k;
            x=fmincon(@(x(1))fAraucoMarkt(x,AraucoEnergy),x0,[],[],[],[],LB,RB,@(x)bedMarkt(x,AraucoEnergy));
        end
    end
end

is this how it should look like? my question would be how do I store all the results now? (sorry if thats a stupid question I am not sooo experianced jet) . But because I have 3 values how do I create a list which stores all the results.

@Matt J the narrowing worked already with fmincon once I dont use itegers the problem is that it is still quite volitile. But I know that there is a point where I can fulfill all my constrains also with the integers. before I did it now in matlab I tried myself a bit in excel and I found at least one set up that works. ( I hope I understood it corect)

thanks a lot again

Greetings

Erik

Torsten 2022-5-4

编辑：Torsten 2022-5-4

在 MATLAB Online 中打开

xf = zeros(1,3);
LB = 0;
RB = 1;
%optval = Inf;
index = 0;
for i = 0:15
    for j = 1:30
        for k = 0:70
            %Fremdkapitalanteil
            x0 = (RBFK-LBFK).*rand(1,1) + LBFK;
            xf(1) = i;
            xf(2) = j;
            xf(3) = k;
            [x,fval]=fmincon(@(x)fAraucoMarkt(x,xf,AraucoEnergy),x0,[],[],[],[],LB,RB,@(x)bedMarkt(x,xf,AraucoEnergy));
            %if fval < optval
            % optval = fval;
            % xopt = x;
            % xopt1 = i;
            % xopt2 = j;
            % xopt3 = k;
            %end     
            index = index + 1;
            Return=fAraucoMarkt(x,xf,AraucoEnergy);
            Results(index,1:4)=[x,xf];
            Results(index,5)=Return;
            Results(index,6)=fminSpeich(x,xf,AraucoEnergy);
            Results(index,7)=fRestschuld(x,xf,AraucoEnergy);      
        end
    end
end

Erik Beste 2022-5-5

I used it and it works perfectly fine thanks a lot all of you !

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Answer 2

Matt J 2022-5-4

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https://ww2.mathworks.cn/matlabcentral/answers/1711390-ga-does-not-find-the-optimal-value#answer_956870

编辑：Matt J 2022-5-4

I was thinking in changing it to a inequality constrain Restschuld is smaller than 1 and bigger than -1

I'm surprised you were even able to run the code in its current form. From the ga documentation:

"When intcon is nonempty, nonlcon must return empty for ceq. For more information on integer programming, see Mixed Integer ga Optimization."

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Erik Beste 2022-5-4

在 MATLAB Online 中打开

@Matt J sorry I changed it

function [c,ceq] = fbedga(x,AraucoEnergy)
%UNTITLED5 Summary of this function goes here
%   Detailed explanation goes here
minSpeicher=fminSpeich(x,AraucoEnergy);
Restschuld=fRestschuld(x,AraucoEnergy);
c(1)=0.1-minSpeicher;
c(2)=(abs(Restschuld))-1;
ceq=[];
end

that was my idea of solving it.

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