Search found 214 matches

by dirkse
1 year ago
Forum: Solvers
Topic: CONOPT4 and MOSEK option files
Replies: 12
Views: 9590

Re: CONOPT4 and MOSEK option files

Fermar, You did not include your model, or any sort of GAMS code to use to reproduce your results, so it's difficult to say exactly what is needed. Looking at your CONOPT options, the most striking thing to me is that you have * Maximum and minimum jacobian element rtmaxj = 1.00e+20 * internal value...
by dirkse
1 year ago
Forum: Modeling
Topic: Loop Function and Parameters Based on a Distribution
Replies: 6
Views: 1874

Re: Loop Function and Parameters Based on a Distribution

Diabolik, Sometimes it is useful to simply put your eyes on the data. In this case, to display and look at the c(j) and d(j) values in each pass of the loop. My guess is that you'll see the d(j) filling up or becoming less sparse. The assignment d(j)$onoff(j) = uniform(20,200); does the expected thi...
by dirkse
1 year ago
Forum: Modeling
Topic: Loop Function and Parameters Based on a Distribution
Replies: 6
Views: 1874

Re: Loop Function and Parameters Based on a Distribution

Hello,

Perhaps this is what you are looking for.

-Steve

Code: Select all

execseed = 86358;

set j / 1 * 20 /;
scalar offProb / 0.8 /;
parameters d(j), onoff(j);
onoff(j) = uniform(0,1);
onoff(j) = 1$[onoff(j) >= offProb];
d(j)$onoff(j) = uniform(20,200);
display onoff, d;
by dirkse
1 year ago
Forum: Modeling
Topic: positive mathematical programming
Replies: 1
Views: 971

Re: positive mathematical programming

Hello,

Marginal values are frequently negative. If we exclude the zero marginal values, I suppose marginals are negative about half the time.

Why do you find it surprising that your marginals are negative?

-Steve
by dirkse
1 year ago
Forum: Solvers
Topic: Equation Listing for nonlinear eqs
Replies: 3
Views: 2529

Re: Equation Listing for nonlinear eqs

Hi, I think you understand the mathematical/numerical content that is there when a nonlinear equation is shown in the listing file. It seems you are not on the same page about the particular form used to convey this information; perhaps I can help explain how this evolved. For simplicity, I just use...
by dirkse
1 year ago
Forum: Solvers
Topic: How to change path solver option during execution
Replies: 1
Views: 1690

Re: How to change path solver option during execution

Hello,

You can write the options file path.opt during GAMS execution via the put facility:

https://www.gams.com/40/docs/UG_Put.html

-Steve
by dirkse
1 year ago
Forum: API
Topic: GAMS parameter initialisation as Modifier in Python GAMSModelInstance
Replies: 2
Views: 4617

Re: GAMS parameter initialisation as Modifier in Python GAMSModelInstance

Of course, if you are sending the MRE (Min Reproducible Example), you should also send the .log and .lst files from your run that exhibits the error.

-Steve
by dirkse
1 year ago
Forum: API
Topic: GAMS parameter initialisation as Modifier in Python GAMSModelInstance
Replies: 2
Views: 4617

Re: GAMS parameter initialisation as Modifier in Python GAMSModelInstance

Hi, This sounds like an interesting problem. If you can provide a minimal sort of example that reproduces this, it seems likely I can provide some useful feedback. As an example, have a look at the obstacle example in the GAMS model library: https://www.gams.com/40/gamslib_ml/libhtml/gamslib_obstacl...
by dirkse
1 year ago
Forum: Syntax
Topic: Subset of multiple subsets
Replies: 4
Views: 6477

Re: Subset of multiple subsets

Martin, The situation you describe has appeared in practice a few times, but fortunately not so often. I usually take the approach of declaring subsets, parameters and variables over the larger set, like this: sets abc /a, b, c/ ab[abc] /a, b/ a[abc] /a/ ac[abc] /a, c/ c[abc] /c/ ; parameter foo[abc...
by dirkse
1 year ago
Forum: Modeling
Topic: Equality constraint not enforced
Replies: 4
Views: 5456

Re: Equality constraint not enforced

Zack, Yes, the log shows that your models are solved properly. I suggest you contact GAMS directly via support@gams.com (or with a phone call) to pursue this matter. It's possible we may need a reproducible example that we can run here in order to resolve this issue. If you can provide that easily, ...