Infeasible solution

GAMS
1

Hello!

First of all I am sorry if this is not the correct place to post this question as I am fairly new to GAMS. Myself and a colleague have encoded the example 2 for the MTG model explicited in the article “Optimal Periodic Scheduling of Multistage Continuous Plants with Single and Multiple Time Grid Formulations” by Pedro M. Castro and Augusto Q. Novais and after running the DICOPT algorithm it finds an infeasible solution. We’ve already reviewed the code countless times and we can’t find the source of the problem, so I would appreciate if anyone knew a strategy to resolve this issue. The gms file is attached.

Thank you in advance.

Best Regards.
MTG EX2.gms (9.38 KB)

2

What I usually do in such a situation, I try to get hold of a feasible solution (perhaps one is reported in the paper or you find a trivial one). Now you initialize all your variables before the solve statement to this reported solution. Next, you turn on the equation listing (modelname.limrow=1e9). GAMS will print all individual equations in the lst file and will have evaluated the equations for you. It will report equations that are infeasible (should not happen for a feasible solution, right?). This is the equation to look at! Search for “INFES” in the equation listing.

-Michael