Search found 11 matches

by chrispahm
1 month ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 160

Re: CPLEX does not find true optimum despite optcr=0

Thanks @ameeraus for the reply and the elegant solution to my problem. As you might have guessed, I totally oversaw that my .fx was actually resetting the lower bound of the variable. If I would have actually set a lower bound of 1 (instead of fixing it), I would have received a matrix error stating...
by chrispahm
1 month ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 160

CPLEX does not find true optimum despite optcr=0

Hi everyone, In a MIP model with option optCR=0; , I face the problem that CPLEX does not return the "true" optimal solution to the problem. When I manually fix some binaries, I can increase the objective value (without breaking any constraints) by more than 1%. I'm sure that this is caused by a mis...
by chrispahm
9 months ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 360

Re: Generate Equation and Column Listing without solving

Hi,
Thanks a lot for that great hint Fred!
I just tried and it seems to work really nice :)

Best,
Christoph
by chrispahm
9 months ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 360

Generate Equation and Column Listing without solving

Dear all, I would like to know if there is a way to generate the equation and column listing of a model without actually solving it (basically dry running the model). The background is that solving the model takes quiet some time, and for debugging I sometimes just want to check if e.g. the dollar c...
by chrispahm
10 months ago
Forum: Tools
Topic: Atom GAMS IDE
Replies: 0
Views: 1083

Atom GAMS IDE

Hi, I worked on a GAMS IDE plugin for the popular Atom editor for the past half-year and thought that it might be of interest for some of you. The plugin is called linter-gams . Atom is an open-source editor maintained by Github, that features a beautiful user-interface, high customizability and a l...
by chrispahm
10 months ago
Forum: Syntax
Topic: Domain checking in sameas (and similar commands)
Replies: 0
Views: 289

Domain checking in sameas (and similar commands)

As so often when writing code, typos happen. When such a typo occurs in a dollar conditional (in my case today using a sameas operator), and the typo happens to be part of the universal set already (because the typo is a set element from a different set), the GAMS compiler doesn't throw an error. Co...
by chrispahm
1 year ago
Forum: Modeling
Topic: Dimension different in GAMS error message
Replies: 2
Views: 353

Re: Dimension different in GAMS error message

You could add a variable where you sum over the countries, but just make it sum over the Netherlands. Then you minimize that variable. I attached a file where I made the appropriate changes to your model.
by chrispahm
1 year ago
Forum: Announcements
Topic: GAMS Studio
Replies: 3
Views: 2717

Re: GAMS Studio

I don't know whether this is the right forum for feedback, so please feel free to move/delete if deemed inappropriate. As I understood correctly, GAMS Studio is supposed to be an Open-Source project. If you are still in an early development phase, something really great for the Open-Source community...
by chrispahm
1 year ago
Forum: API
Topic: model2tex
Replies: 4
Views: 1761

Re: model2tex

Thanks a lot for your help! I totally forgot to reply that removing the SOS variables did indeed resolve the issue.
by chrispahm
1 year ago
Forum: API
Topic: model2tex
Replies: 4
Views: 1761

Re: model2tex

Hi Celmens, thanks a lot for your reply! I will try removing the SOS variables tomorrow. Another question I have is whether there are any plans to publish the model2tex source code. The background is that I would like to create a little script where I could quickly transform single GAMS equations in...