Conversion to logical from optim.prob​lemdef.Opt​imizationC​onstraint is not possible. Expressing a condition for a parameter.

Hello,

I am trying to formulate an mixed integer optimization problem and one of my parameters (say A) depends on my optimization variable (say x), which is a binary variable.

I would like that when x=1, A=a and when x=0, A=b;

I realized that I couldn't express it with an "If function" after getting the error Conversion to logical from optim.problemdef.OptimizationConstraint is not possible.

Going through Matlab resources I found solutions using big M constraints for cases where A is expected to be above a superior value when x takes a certain value. However I couldn't find the case where A has to be equal to a specific value.

Can someone help me expressing this condition?

Thank you! :)

Answer 1

[Walter Roberson]

A = b + x*(a-b)

[Lenilein]

Brillant, thanks!!

[NN]

how can i use the same Pbatt which is calculated from optimisation variables depending on its sign in objective function?

Like if Pbatt is positive i have to multiply with cost and if its negative i have to multiply it with another cost .How do i specify Pbatt in objective function accordingly ?

I am also getting the error

Conversion to logical from optim.problemdef.OptimizationConstraint is not possible.

i have used below code.

for i = 1:N
     
        if PbattV == 200
          Cost1 = Costa;
        elseif PbattV == -200
            Cost2 = Costb;
        end
end
prob.Objective = dt*Cost1'*PbattV +Cost2'*PbattV;

Kindly help