Search found 210 matches

by bussieck
1 day ago
Forum: Announcements
Topic: ORISE Fellowship at EPA
Replies: 0
Views: 12

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
4 days ago
Forum: Announcements
Topic: European Commission, Joint Research Centre - Economic Modeller Positions
Replies: 0
Views: 42

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
3 weeks ago
Forum: API
Topic: A problem about .Net API and GAMS
Replies: 2
Views: 212

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
3 weeks ago
Forum: Tools
Topic: Debugger
Replies: 4
Views: 11562

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
3 weeks ago
Forum: Modeling
Topic: GAMS return code not 0 (407)
Replies: 2
Views: 74

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...
by bussieck
3 weeks ago
Forum: Syntax
Topic: Sqrt domain x < 0 error
Replies: 2
Views: 123

Re: Sqrt domain x < 0 error

Not sure how to make this more abvious. The log says "*** Error at line 31: sqrt: FUNC DOMAIN: x < 0", the source echo of line 31 reads: 31 TLM(i,j,k) = (2/3*(sqrt(((T1hot(i,k)-T1cold(j,k))*(T2hot(i,k)-T2cold(j,k)))))) + (1/3*((T1hot(i,k)-T1cold(j,k))+(T2hot(i,k)-T2cold(j,k))/2)) ; There is a single...
by bussieck
4 weeks ago
Forum: Syntax
Topic: Properly formulating NLP - syntax issues
Replies: 1
Views: 70

Re: Properly formulating NLP - syntax issues

It's seems not a compilation error but anb evaluation error during the solve. Just from the algebra, there is nothing that prevents the solver to move the variables so that sales_price(k)-subsidy(k) becomes negative. Sure the point is probably not optimal, probably not even feasible, but the solver ...
by bussieck
4 weeks ago
Forum: Modeling
Topic: How to write the constraints in GAMS efficiently?
Replies: 1
Views: 92

Re: How to write the constraints in GAMS efficiently?

There is a long discussion with an answer to this question in the following thread: viewtopic.php?f=9&t=10634&p=24730#p24693

-Michael
by bussieck
4 weeks ago
Forum: Modeling
Topic: How to simplify the CCGT unit commitment model?
Replies: 7
Views: 949

Re: How to simplify the CCGT unit commitment model?

I think you still have difficulties organizing your data in a relational form. You might want to talk to your database friends/colleagues how to organize data in a relational database. That's also the way to organize data in GAMS. The choice of label names suggest the same thing. You try to put stru...
by bussieck
4 weeks ago
Forum: Syntax
Topic: searching string in set
Replies: 11
Views: 194

Re: searching string in set

Doing set member ship based on the name of a label is not what you should do in GAMS. We make this difficult on purpose, because that is a fragile thing. Better be explicit about it: set X /y1*y3, z1* z2/, Y(X) / y1*y3 /; Parameter w(X) /y1 10, y2 20, y3 30, z1 40, z2 50/; Scalar ysubsum; ysubsum = ...