Search found 215 matches

by bussieck
5 hours ago
Forum: Modeling
Topic: Execution Error : Division by zero
Replies: 2
Views: 15

Re: Execution Error : Division by zero

GAMS is pretty precise giving you pointers to your problem. In the listing file you find: **** Exec Error at line 188: division by zero (0) line 188 reads 188 augm_obj.. sum(o1,dir(o1)*b(o1)) + 1e-3*sum(om1,sl(om1)/(maxobj(om1) - minobj(om1))) =e= a_objval; Fortunately, there is only one division by...
by bussieck
2 days ago
Forum: Modeling
Topic: Assigning values for mappings
Replies: 1
Views: 50

Re: Assigning values for mappings

The compiler complains with: 5 Parameter C(j) /632.645 1000/; **** $122 $148 **** 122 One dimensional set expected **** 148 Dimension different - The symbol is referenced with more/less **** indices as declared Even though j is two-dimensional, GAMS declaration statements need one-dimensional domain...
by bussieck
6 days ago
Forum: Modeling
Topic: How to use non-binary variable in a conditional statement MILP
Replies: 1
Views: 77

Re: How to use non-binary variable in a conditional statement MILP

Similar questions have been asked before. Search for "logic constraints" or "williams" (that's a name of an author for a book that teaches that). So here only a short answer: A<B => C=1 is equivalent to C=0 => A > B. This we can do with a linear constraint (and binary variable C): A > B - (B-A.lo)*C...
by bussieck
1 week ago
Forum: Syntax
Topic: Syntax error for EMP equilibrium problem
Replies: 2
Views: 118

Re: Syntax error for EMP equilibrium problem

Look at the EMP info file you produce (e.g. do a gamskeep and look into the 225a directory at file empinfo.dat). Line 3 reads: q('a1','j2','n2') q('a1','j3','n2') Ka('a1','n3') theta('a1','n3') R('a1','n3') I('a1','n3') q('a1','j1','n3') q('a1','j2','n3') q('a1','j3','n3') Ka('a1','n4') theta('a1','...
by bussieck
1 week ago
Forum: Solvers
Topic: *** Failure calling solver: CONOPT4 (rc=1). What does it mean?
Replies: 5
Views: 179

Re: *** Failure calling solver: CONOPT4 (rc=1). What does it means?

It means that Conopt4 crashed. Conopt4 was introduced with GAMS 24.8 and is still under heavy development as you can see from the release notes (https://www.gams.com/latest/docs/RN_MAIN.html). Every major release came with an update of Conopt4. So you should see if you can reproduce the failure with...
by bussieck
4 weeks ago
Forum: Announcements
Topic: ORISE Fellowship at EPA
Replies: 0
Views: 851

ORISE Fellowship at EPA

Crossposting from GAMS-L by Andrew Schreiber: Hi folks, We have a research fellowship in the EPA’s National Center for Environmental Economics that may be a good fit for recent Masters or PhD graduates. It is a one year + fellowship where the individual would have an opportunity to work closely with...
by bussieck
1 month ago
Forum: Announcements
Topic: European Commission, Joint Research Centre - Economic Modeller Positions
Replies: 0
Views: 397

European Commission, Joint Research Centre - Economic Modeller Positions

Cross posting from GAMS-L by Emanuele Ferrari: Dear all, The Unit "Economics of Agriculture" located in Seville (Spain) is part of the European Commission's Joint Research Centre. It has 2 job opportunities with the following profiles: One researcher to contribute to the Integrated policy analysis o...
by bussieck
1 month ago
Forum: API
Topic: A problem about .Net API and GAMS
Replies: 2
Views: 289

Re: A problem about .Net API and GAMS

I suggest you do what the error message tells you: " ...set GAMSWorkspace.Debug to KeepFiles or higher or define the GAMSWorkspace.WorkingDirectory to receive a listing file with more details ". The exception means the GAMS compiler had compilation errors. I guess the call the gdxxrw did not work (p...
by bussieck
1 month ago
Forum: Tools
Topic: Debugger
Replies: 4
Views: 11652

Re: Debugger

It's a method that's independent of many things. If you need to "debug" at too many places at once, that you need to inject the code at too many places, and therefore it becomes at some stage not very usable.

-Michael
by bussieck
1 month ago
Forum: Modeling
Topic: GAMS return code not 0 (407)
Replies: 2
Views: 124

Re: GAMS return code not 0 (407)

The error code means "unexpected error" (see https://www.gams.com/latest/docs/UG_GAMSReturnCodes.html). You need to look at the log file of this run call. This hopefully will tell you more. When you create the workspace you can provide some option to keep the temporary directory and the files. -Mich...