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Newbie with GAMS

Posted: Tue Mar 26, 2019 4:25 am
by ManT
Hello All,

I am rather a newbie with GAMS. My model yields an infeasible solution when solved. I suspect, I have not handled the absolute function in the constraint formulation defined in equation 37-52 (see attached files). Any advise or guidance would be greatly appreciated.

Re: Newbie with GAMS

Posted: Wed Mar 27, 2019 12:03 pm
by saghafiiii
Hi

I'm afraid that some of your equations have been entered wrongly!
for example look at constraint 40!
Am I right?

Re: Newbie with GAMS

Posted: Wed Mar 27, 2019 5:45 pm
by ManT
Many thanks for your corrections. I have fixed it. I still have an infeasible solution. See attached GAMS file. Any advice would be appreciated.

Re: Newbie with GAMS

Posted: Thu Mar 28, 2019 11:09 am
by saghafiiii
Hi again,

I think infeasibility comes from the constraints below:

Code: Select all

r5.up   = 2.40;
r5.lo   =0;
if you comment these two constraints there is no infeasibility.
I do not know exactly but r5 make the objective function badly constrained.