Search found 1049 matches
- 1 year ago
- Forum: Modeling
- Topic: Assistance with conditional non-equals
- Replies: 4
- Views: 3132
Re: Assistance with conditional non-equals
I have no idea what you are asking. The attached GAMS model runs though nicely. I don't find any .fx, I only find some .l in your code. They have no effect (since a MIP solver usually ignores the starting point if not instructed otherwise). If I turn the .l into .fx I still get a good solution but w...
- 1 year ago
- Forum: API
- Topic: Trouble installing Python GAMS API on Mac OS
- Replies: 5
- Views: 8745
Re: Trouble installing Python GAMS API on Mac OS
You have a Mac with an M1 or M2 chip but the GAMS 34 distribution is Intel only. So you would need an Intel Python running under Rosetta 2 on you machine. The native M1/M2 port for GAMS was introduced with GAMS 43 (see https://www.gams.com/latest/docs/RN_43.html#g4310_PLATFORMS). So many good reason...
- 1 year ago
- Forum: Syntax
- Topic: ERROR 790 AND 257 IN THE LAST SENTENCE
- Replies: 1
- Views: 5197
Re: ERROR 790 AND 257 IN THE LAST SENTENCE
You don't have a bi-level optimization problem. You have a two-stage stochastic program! The GAMS compiler gives you good help: 171 solve project max z use EMP scenario dict; **** $790,257 **** 257 Solve statement not checked because of previous errors **** 790 Symbol dimension mismatch **** The fol...
- 1 year ago
- Forum: Solvers
- Topic: How to deal with degenerate solutions
- Replies: 4
- Views: 8260
Re: How to deal with degenerate solutions
and it starts reporting solutions, which I've interpreted, rightly or wrongly, as the model finding solutions with the same objective value. This is wrongly assumed. If you would have send the entire width of the log I could have shown you the difference in incumbent values. With what you sent I ca...
- 1 year ago
- Forum: Tools
- Topic: Model status Infeasible when using GUSS
- Replies: 1
- Views: 9274
Re: Model status Infeasible when using GUSS
Not clear what problem you describe. When I run the model you uploaded I get: --- Scenario s0: Records read: 4650 --- Solution statistics for scenario s0 --- Unmatched Records 0 --- Solver Status 1 Normal Completion --- Model Status 1 Optimal --- Objective Value 2.80346e+09 --- Resource Usage 281.79...
- 1 year ago
- Forum: Solvers
- Topic: How to deal with degenerate solutions
- Replies: 4
- Views: 8260
Re: How to deal with degenerate solutions
Hi ,not sure I understand everything what you write here. Degeneracy usually means (see https://glossary.informs.org/second.php?page=D.html#Degeneracy) that we have multiple solution of the same value. You describe that Cplex "always identifies several hundred solutions prior to solving". ...
- 1 year ago
- Forum: Solvers
- Topic: System limits were reached on cluster
- Replies: 7
- Views: 9983
Re: System limits were reached on cluster
UCM_h.log This all looks very much like the cluster is killing your jobs. GAMS runs the solver as an executable (communicating the model instance via scratch files) so even if the solver dies, the GAMS job should nicely continue and write proper lst files. Since this does not happen (and since the ...
- 1 year ago
- Forum: Solvers
- Topic: System limits were reached on cluster
- Replies: 7
- Views: 9983
Re: System limits were reached on cluster
In order to run this, we would need a GDX file. Can you supply one? Moreover, the export to Excel can be improved (performance). Rather than calling gdxxrw for each variable/parameter, you can create (at compile $on/offEcho or execution time $on/offPut) a gdxxrw instruction file: $if not %PrintResul...
- 1 year ago
- Forum: Solvers
- Topic: System limits were reached on cluster
- Replies: 7
- Views: 9983
Re: System limits were reached on cluster
What does "System limits" actually refers to in this context ? GAMS has some internal limits, e.g. the number of variables a model can have <2.1e9 and other limits. This is what this return code means. I am a little surprised that the log did not give you more information on what limit wa...
- 1 year ago
- Forum: Syntax
- Topic: Importing Data From Excel
- Replies: 4
- Views: 5595
Re: Importing Data From Excel
Sebastian,
On professional development. I can recommend Bruce McCarl's GAMS classes. He starts one next week. See https://www.gams.com/courses/.
-Michael
On professional development. I can recommend Bruce McCarl's GAMS classes. He starts one next week. See https://www.gams.com/courses/.
-Michael