Search found 1038 matches
- 9 months ago
- Forum: Modeling
- Topic: Problem infeasible or unbounded
- Replies: 1
- Views: 2647
Re: Problem infeasible or unbounded
Nothing. You should use code boxes for your model and output though. You model in unbounded. Just limit the objective variable (e.g. z.lo = -1e6;) and see what "run away" variables you get. Check your application why this should not happen, turn your insight into constraints/model logic. -...
- 10 months ago
- Forum: Syntax
- Topic: dimension error
- Replies: 5
- Views: 5754
Re: dimension error
The attached program succeeds without a problem. If I remove the $stop and let GAMS continue, I get compilation errors when compiling "startup(s*,i,t)", you probably means "startup(s,t,*,i)" at least that makes sense from the code you have later. Now after fixing all this, I get ...
- 10 months ago
- Forum: Syntax
- Topic: dimension error
- Replies: 5
- Views: 5754
Re: dimension error
Don't just paste your GAMS source as normal text. There are fine code boxes in the forum editor. Also this issue is related to data so upload your Excel and GDX file as well so one can reproduce the error.
-Michael
-Michael
- 10 months ago
- Forum: API
- Topic: Trouble installing Python GAMS API on Mac OS
- Replies: 5
- Views: 4792
Re: Trouble installing Python GAMS API on Mac OS
Yes. -Michael
- 10 months ago
- Forum: Modeling
- Topic: How do I formulate logical expressions in equations with variables??
- Replies: 4
- Views: 2759
Re: How do I formulate logical expressions in equations with variables??
Look for logic equations in the forum. It is a frequently asked questions.
-Michael
-Michael
- 10 months ago
- Forum: Syntax
- Topic: Loading data from Excel Sheet into GAMS
- Replies: 4
- Views: 5480
Re: Loading data from Excel Sheet into GAMS
Please read the documentation of gdxxrw at https://www.gams.com/latest/docs/T_GDXXRW.html. All parameters are read with the index k and the value of the parameter in the neighboring cell. Your sheets don't mention the index (k) at all. You did not provide the elements of set k, but here I am assumin...
- 10 months ago
- Forum: Modeling
- Topic: Assistance with conditional non-equals
- Replies: 4
- Views: 2039
Re: Assistance with conditional non-equals
I see. Debugging models is hard. What you need to do is to take be "better" solution you get by just providing the .l (or leave this out because it has no effect) and look at this solution. Explain the solution to yourself and detect the flaws in this solution. Next look at the equation th...
- 10 months ago
- Forum: Syntax
- Topic: Dimension Different Error (electricity pricing model)
- Replies: 2
- Views: 4160
Re: Dimension Different Error (electricity pricing model)
I think you need to upload something that lets us reproduce the error. I can't do this from the code snippets you have pasted.
-Michael
-Michael
- 10 months ago
- Forum: Syntax
- Topic: Loading data from Excel Sheet into GAMS
- Replies: 4
- Views: 5480
Re: Loading data from Excel Sheet into GAMS
Sure, if you provide the Excel files to see what's going on.
-Michael
-Michael
- 10 months ago
- Forum: Modeling
- Topic: Assistance with conditional non-equals
- Replies: 4
- Views: 2039
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...