Search found 16 matches

by chrispahm
2 months ago
Forum: Contributed Documentation and Tools
Topic: Data storytelling in operations research
Replies: 0
Views: 1038

Data storytelling in operations research

Hey there :) I'd like to use the opportunity to showcase a piece we have done regarding interactive "data-story" notebooks using GAMS. An Introduction to operations research in Observables https://user-images.githubusercontent.com/20703207/87766667-d1ee1480-c819-11ea-9d1c-c8db46ffb17a.png The Observ...
by chrispahm
5 months ago
Forum: Bugs
Topic: GDXIN produces compilation error in dump file
Replies: 2
Views: 559

Re: GDXIN produces compilation error in dump file

Thanks a lot for your help! The workaround is sufficient for me (for the time being)

Best
Christoph
by chrispahm
5 months ago
Forum: Bugs
Topic: GDXIN produces compilation error in dump file
Replies: 2
Views: 559

GDXIN produces compilation error in dump file

Hi there, I'm running a model with the command line parameter `dumpOpt=11` in order to generate a single GAMS file containing all includes and data. However, using $GDXIN with 0 level elements seems to create a compilation error in the .dmp file: Simplified (reproducible) problem (which compiles fin...
by chrispahm
1 year ago
Forum: Modeling
Topic: Writing model tests - best practices
Replies: 4
Views: 969

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
1 year ago
Forum: Modeling
Topic: Writing model tests - best practices
Replies: 4
Views: 969

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
1 year ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 858

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 year ago
Forum: Modeling
Topic: CPLEX does not find true optimum despite optcr=0
Replies: 2
Views: 858

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
2 years ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 993

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
2 years ago
Forum: Modeling
Topic: Generate Equation and Column Listing without solving
Replies: 3
Views: 993

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
2 years ago
Forum: Tools
Topic: Atom GAMS IDE
Replies: 0
Views: 1706

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...