GAMS World Forum

Thanks Steve, I found the issue. Doing wasn't good. I'm going with your initial suggestion to relax y.

Hi Steve\Everyone, Were you able to find the problem? I have added a dummy variable, dummy(i,j) and a dummy constraint, con12, and placed dummy(i,j) in con4 and con5, and it says it's infeasible. But if you take out dummy(i,j) from con4 and con5, and comment out con12, it works fine, and both are su...

Hi Steve,

I have attached my code here.

Thanks.

Thanks for your response Steve. As indicated in my follow-up post, the problem is with s(i,j). And it behaves in a manner I believe is strange. For instance, if I replace con11 with s(i,j) =E= 1 it does not run at all and claims it is infeasible. Nevertheless, if I remove con11 and use .fx for all m...

Ah I see. That's interesting. Thanks!

I've worked on it some more and come across a rather strange problem. The problem is with s(i,j); for some reason, it doesn't want to be anything but 0. Two experiments: 1. Set s(i,j) in con11 to a fixed value such as 0.5 (instead of the rhs function) while keeping s(i,j) in con4 and con5. This won'...

Hi,

Assuming your set C contains the elements {i,j,k,l}, and j is just an element. Then, you can write the following:

Hello Everyone, I'm currently working on a bi-level optimization model that seems to behave strangely. Please find my equations below. I have set Bgt=30 and Cf=30. Therefore, per constraint 1 (con1), both et(i,j)=0 and ek(i,j)=0 for all eligible (i,j) pairs. This is what the solver selects. Then, pe...