Optimization problem on Constraint declaration
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Soumili Sen
am 18 Nov. 2020
Kommentiert: Soumili Sen
am 19 Nov. 2020
Hello,
I have a code
syms a wd;
c4_update=0.0248*abs(a)^4 - 9.878; %coming from some other equation
c3_update=abs(wd*(- 0.02+ a*(0.040 - 0.1352i)) + 0.223 - 0.223i)^2 + 0.223+ 0.223i)^2 + a*(0.096- 0.089i)) + 0.22 - 0.223i)^2 % coming from some other equation
nonlcon =@constraintfcn;
[x_value2,fval2] = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon2,opts); % where fun,x0,A,b,Aeq,beq,lb,ub,opts are well defined
function [c,ceq] = constraintfcn(c3_update,c4_update)
c(1)= c3_update(1);
c(2)=c4_update(1);
ceq = [];
end
It gives error. How to solve this problem.
3 Kommentare
Matt J
am 18 Nov. 2020
Yes, but you haven't copy/pasted the full error message, so we cannot see where the error is coming from.
Akzeptierte Antwort
Matt J
am 18 Nov. 2020
Bearbeitet: Matt J
am 18 Nov. 2020
We can't tell from your code what the relation is supposed to be between a, wd and x. This might be what you were trying to do, however:
nonlcon =@constraintfcn;
[x_value2,fval2] = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon2,opts); % where fun,x0,A,b,Aeq,beq,lb,ub,opts are well defined
function [c,ceq] = constraintfcn(x)
a=x(1); wd=x(2);
c(1)= abs(wd*(- 0.02+ a*(0.040 - 0.1352i)) + 0.223 - 0.223i)^2 + 0.223+ 0.223i)^2 + a*(0.096- 0.089i)) + 0.22 - 0.223i)^2;
c(2)=0.0248*abs(a)^4 - 9.878;
ceq=[];
end
5 Kommentare
Matt J
am 19 Nov. 2020
Bearbeitet: Matt J
am 19 Nov. 2020
Both the constraint and objective functions must be a function of your unknown variable vector x (and nothing else). You can make the definition of the constraint function depend on other fixed problem parameters, however that definition must remain fixed throughout the optimization. During the optimization, the only thing that is allowed to vary the output of the constraint and objective functions are the different guesses for the unknowns that fmincon will iteratively pass in as input.
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