Good Day,

Please i wrote a GAMS model to minimize the total costs associated with water exchange between four (4) participating process plants and a centralized resources exchange hub.

I obtained the following results after running the model:

**** SOLVER STATUS 1 Normal Completion

**** MODEL STATUS 5 Locally Infeasible

“** Infeasible solution. Reduced gradient less than tolerance”

Please how do i detect where the errors emanates from? How to solve/avoid such problems and how should i add bounds and limits to my problem.

The .gms file is attached.

GAMS MODEL.gms (21.3 KB)

Thank you and Best Regards

If you use a global solver like BARON you get the certificate that the model is indeed infeasible. The forum has many topics that explain how to deal with infeasible models. IIS is one way. In your case the IIS found by BARON is pretty large: (I)IS contains 188 rows and 219 columns . So this is not so helpful. Other debugging techniques might be better. Good luck.

-Michael