GAMS World Forum

Hi Maria

H.FX(v,d,h,j,"1") = 1;

Cheers
Renger

Hi Qiaomin
This question is hard to answer without seeing the complete code, so you might want to attach your code.
CHeers
Renger

Hi
This is the optimal solution imagine a one-dimensional problem: x<5 and z=3x. 0 is the optimal solution.
It would make more sense if you would have >= constraints.
Cheers
Renger

Hi Indeed, it is not the optimal solution, although you have this in the listing: MIP Solution: -375.869834 (1430 iterations, 15 nodes) Best possible: -375.869834 Absolute gap: 0.000000 Relative gap: 0.000000 If I use couenne or bonmin (both are free and global solvers), I get the "correct"...

Hi Feifan

How do you know that the solution is not optimal? Constraint 4 and 5 could have an impact on the choice of the variables.
(It is hard to check without the Gams code).
Cheers
Renger

Hi There is nothing wrong with your solution: you have three less-than-or-equal constraints and a to minimize objective equation all with positive coefficients. This means that {0,0,0} is the minimal and optimal solution. All constraints are met and the objective variable is minimized. Perhaps you m...

Hi The only equation in the model used with a division is: augm_obj.. sum(o1,dir(o1)*b(o1)) + 1e-3*sum(om1,sl(om1)/(maxobj(om1) - minobj(om1))) =e= a_objval; so, it looks like the difference between maxobj(om1) and minobj(om1) gets zero for a certain or all om1. You could rewrite the equation by add...

Hi Vahdi

You will find the answer in the first example of the GDXXRW documentation.

Cheers
Renger

Hi
Conopt4, as far as I can see in the documentation, came with GAMS version 25.1. Perhaps you have an older version of GAMS.
Just try 'option nlp=conopt;' (assuming you are trying to solve an NLP problem).

CHeers
Renger

It sounds a little bit weird but perhaps https://www-01.ibm.com/support/docview. ... wg21399979 can explain it.
Cheers
Renger