GA for Mixed-Integer Nonlinear Programing

1 view (last 30 days)
Hoang Trinh
Hoang Trinh on 28 Apr 2020
Commented: Hoang Trinh on 30 Apr 2020
Dear all,
I am having a problem with solving a MINLP with GA solver. It keeps having the message of "Constraint function must return real value". I have double checked all the constraints and they should be fine. But this message still appeared. May I ask whether Matlab 2018b can show the contraint that has a problem? I would really appreciate your help.
Thank you so much,
Kind Regards,
Hoang Trinh,
  8 Comments
Walter Roberson
Walter Roberson on 29 Apr 2020
A(51,55) = 1;
A(51,53) = -1;
That expresses that (1) * x(55) + (-1) * x(53) <= b(51) . b(51) is 0, so you are expressing that x(55)-x(53) <= 0, which is to say that x(55) <= x(53) . But that still allows them to be equal, and when they are equal, you get the division by 0.
Linear constraints are A*x' <= b not A*x' < b.
If you want < then you need to make b(51) negative, even if it is only -realmin()
Hoang Trinh
Hoang Trinh on 30 Apr 2020
I have made some changes like this:
A(51,55) = 1;
A(51,53) = -1;
A(72,56) = 1;
A(72,55) = -1;
with
b(51) = 0.1 ;
b(72) = 0.1 ;
So now, x(55) - x(53) <= 0.1 ; and x(56) - x(55) <= 0.1;
Still, the error has not been fixed. :(

Sign in to comment.

Answers (0)

Categories

Find more on Get Started with Optimization Toolbox in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!