Optimization problem on Constraint declaration
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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 个评论
Matt J
2020-11-18
It gives error.
An error you haven't shown us...
Soumili Sen
2020-11-18
Matt J
2020-11-18
Yes, but you haven't copy/pasted the full error message, so we cannot see where the error is coming from.
采纳的回答
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 个评论
Soumili Sen
2020-11-19
Matt J
2020-11-19
For any fixed value of x, your constraint function constraintfcn(x) must return the same value all the time. The defintiion of the function is not allowed to evolve, stochastically or otherwise, throughout the optimization.
Soumili Sen
2020-11-19
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.
Soumili Sen
2020-11-19
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