Search found 24 matches
- 1 year ago
- Forum: Modeling
- Topic: Equality constraint not enforced
- Replies: 4
- Views: 5663
Re: Equality constraint not enforced
Hi Steve, Thanks for the response, but that is the shocking part - The model isn't infeasible. Attached is the log file. I am not attaching the .lst yet, as it is 70MB and might need to share directly with you. The model actually solves with zero gap: image.png Here is the log file. Ignore the first...
- 1 year ago
- Forum: Modeling
- Topic: Equality constraint not enforced
- Replies: 4
- Views: 5663
Equality constraint not enforced
Hello, I have a simple equation which states a variable X is exactly equal to another variable Y (e.g X =E= Y). Specifically my equation is as follows: EQ_TOTAL_COST_CO2_2(nodes).. dv_total_annual_co2(nodes) =E= pdv_total_annual_co2_taxable(nodes); However, it seems this equation is not being enforc...
- 2 years ago
- Forum: Modeling
- Topic: Different GAMS versions giving very different answers+ weird behavior
- Replies: 4
- Views: 3243
Re: Different GAMS versions giving very different answers+ weird behavior
Do you have a suggestion for a different solver? I tried using the cbc solver, but it won't solve it even after an hour. I am going to try to let it run overnight. But maybe you have a suggestion or temporary/trial solver license I can use for this purpose?
- 2 years ago
- Forum: Modeling
- Topic: Different GAMS versions giving very different answers+ weird behavior
- Replies: 4
- Views: 3243
Re: Different GAMS versions giving very different answers+ weird behavior
Hello Michael, I am sorry to report this is resurfacing with a much newer version of GAMS (35.0). As you can see below, the solution is stopping at ~50% gap(18283.8 Best Bound / 33390.9 Best Integer), and suddenly jumps to reporting 35858.85 (Best possbile) as the optimal solution, with a .7% gap. H...
- 2 years ago
- Forum: Modeling
- Topic: Equations with zero relations taking very long to build
- Replies: 2
- Views: 2753
Re: Equations with zero relations taking very long to build
Thank you Michael, This was the issue. I was experimenting with using the upper limit on variables as a conditional (i.e. $(myvariable.up>0)), instead of the proper approach which is to set it as a flag (map) and use that. I didn't realize the .up was being evaluated each time it was called. Once I ...
- 2 years ago
- Forum: Modeling
- Topic: Equations with zero relations taking very long to build
- Replies: 2
- Views: 2753
Equations with zero relations taking very long to build
Hello, I have a large model, which is taking a long time to get through the model generation. Once it makes it past that, it is rather quick for the size of the model. To track the performance issue with model generation, I followed the steps outlined in https://www.gams.com/35/docs/UG_ExecErrPerfor...
- 2 years ago
- Forum: Modeling
- Topic: random 'matrix error' inconsistent across GAMS installations
- Replies: 1
- Views: 2107
random 'matrix error' inconsistent across GAMS installations
Hello, Lately I have noticed a strange error on disparate projects (maybe 1 of every 100 runs, but random). The error is a 'Matrix error - bounds on discrete variables have to be integer'. Two things make this error strange: (1) my bounds are integer. I know this because they are set in an iterative...
- 3 years ago
- Forum: Syntax
- Topic: csv2gdx creates <empty> rows when trying to read in set
- Replies: 6
- Views: 4717
Re: csv2gdx creates <empty> rows when trying to read in set
That is strange. When I use my data and code, I get what is shown below in a display call: ---- 13 SET opexstreams Domain loaded from text1 position 2 , setName2_el1 , setName2_el2 , setName2_el3 setName2_el4 , setName2_el5 , setName2_el6 , setName2_el7 setName2_el8 , setName2_el9 , setName2_el10, s...
- 3 years ago
- Forum: Syntax
- Topic: csv2gdx creates <empty> rows when trying to read in set
- Replies: 6
- Views: 4717
Re: csv2gdx creates <empty> rows when trying to read in set
Thanks for the response Renger. Let me clarify. What we are trying to do is reduce the number of sets defined directly in the code using this style: sets SetName1 'here is an example set' / setName1_el1, setName1_el2, setName1_el3, setName1_el4/ SetName2 'here is another example set' / setName2_el1,...
- 3 years ago
- Forum: Syntax
- Topic: csv2gdx creates <empty> rows when trying to read in set
- Replies: 6
- Views: 4717
csv2gdx creates <empty> rows when trying to read in set
Hello team, We are trying to create a csv file from which we can read in all the sets in our model, instead of declaring them inline. The csvfile looks like this in excel : image.png and like this in a text editor image.png The command to read this in is as follows: $call csv2gdx ./setDeclarations.c...