Search found 13 matches

by chrispahm
1 month ago
Forum: Modeling
Topic: Writing model tests - best practices
Replies: 4
Views: 304

Re: Writing model tests - best practices

Thanks Steve and Renger for your replies, So again a short note about our current procedure: We don't do the tests manually anymore, as we wrote an R-script that automates the process: 1) On every SVN update, a post-commit hook on the SVN server runs the R-script, which in turn runs the GAMS batch f...
by chrispahm
2 months ago
Forum: Modeling
Topic: Writing model tests - best practices
Replies: 4
Views: 304

Writing model tests - best practices

Here at our institute, we work on a couple of (larger scale) economics related GAMS models. Different teams, involved in different projects make adaptations to the models in order to answer their specific research questions. The models are equipped with a Graphical User Interface (GUI), and are vers...
by chrispahm
5 months ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 338

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
5 months ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 338

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
1 year ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 474

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
1 year ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 474

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
1 year ago
Forum: Tools
Topic: Atom GAMS IDE
Replies: 0
Views: 1200

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
1 year ago
Forum: Syntax
Topic: Domain checking in sameas (and similar commands)
Replies: 0
Views: 353

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: 463

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: 3138

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...