Search found 16 matches

by gamsadmin
3 years ago
Forum: Modeling
Topic: how to model loop in another loop?
Replies: 2
Views: 2683

Re: how to model loop in another loop?

Hi You could write this as one condition: loop (it$((UB1-LB1)>TOL and (UB-LB)>TOL)), statement1 statement2 ); If you want to use two loops, you need to make an alias for it: alias(it, ait) loop (it$((UB1-LB1)>TOL), loop (ait$((UB-LB)>TOL), statement1 statement2 ); ); Cheers Renger
by gamsadmin
3 years ago
Forum: Modeling
Topic: How to add Constraints inside a loop in GAMS
Replies: 1
Views: 1890

Re: How to add Constraints inside a loop in GAMS

Hi You could introduce a flag. Here the idea in code: set lnr /1*10/; parameter flag(lnr); flag(lnr) = 0; flag("1") = 1; equations constrflagged 'The constraint you want to be flagged', .... constrflagged$flag(lnr).. ... model mymodel /all/; loop(lnr, solve mymodel ... ); Cheers Renger
by gamsadmin
3 years ago
Forum: Solvers
Topic: Different solutions with MCP and NLP formulation
Replies: 1
Views: 3666

Different solutions with MCP and NLP formulation

Hi I am running the famous dice problem from entropy econometrics. I formulated an NLP and an MCP model (Goland, Judge, Miller, Maximum Entropy Econometrics, Chapter 2). If I assume that the average of dice throws is 2, I get the same distribution for the probabilities. If I choose 1.5 as the averag...
by gamsadmin
4 years ago
Forum: Archive Google Group
Topic: MCP solver Infeasible
Replies: 6
Views: 10070

Re: MCP solver Infeasible

Then you run the model that solves for L and then you just write for the second model L.FX(t) = L.L(t); (you might want to use a result parameter to do this resultsL(t) = L.L(t); L.FX(t) = resultsL(t); Be aware that a variable is fixed for all model solves after the fixture. If you want to "unf...
by gamsadmin
4 years ago
Forum: Syntax
Topic: Benchmark checked with iterlim=0 but GAMS does not find solution with iterlim>0
Replies: 7
Views: 5113

Re: Benchmark checked with iterlim=0 but GAMS does not find solution with iterlim>0

Hi JM It seems your SAM is not perfectly balanced. 1E-4 shows that there are balance problems. The solver tries to find a solution with the maximum infeasibility below the tolerance level (something like 1E-7), so it can't find a solution because the imbalances are too big and a few imbalances can't...
by gamsadmin
5 years ago
Forum: Syntax
Topic: Infeasible solution for Hydro Optimization Problem
Replies: 1
Views: 2339

Re: Infeasible solution for Hydro Optimization Problem

Hi If you check your output, you will see that two of the energylim equations are limited. You limit the total production by P4capacity, so there be at least enough capacity to produce energy(g). However, There is no feasible solution because the maximum capacity is less than the demand Cheers Renge...
by gamsadmin
5 years ago
Forum: Modeling
Topic: Private ''help'' for academic purposes :-)
Replies: 2
Views: 2672

Re: Private ''help'' for academic purposes :-)

Sure, if you write me some papers so that I will receive the Nobel price in a few years.
Cheers
Renger
by gamsadmin
5 years ago
Forum: Modeling
Topic: Traffic constraint
Replies: 1
Views: 2006

Re: Traffic constraint

by gamsadmin
5 years ago
Forum: Tools
Topic: Reading Data from Excel , except some Cells
Replies: 6
Views: 5380

Re: Reading Data from Excel , except some Cells

Hi
For this you can use gdxxrw (there is a comprehensive documentation with lots of examples: https://www.gams.com/latest/docs/T_GDXXRW.html ). If there is no value in the spread sheet, this is no problem.
Cheers
Renger
by gamsadmin
5 years ago
Forum: API
Topic: Solvers error when calling from MatLab
Replies: 7
Views: 12763

Re: Solvers error when calling from MatLab

Hi It would be more useful if you attach the model you are trying to solve then letting us go through 500 lines looking for an error message. And: you could also have done what Fred and I suggested: run a simple gams file with option subsystems And show the output in your post to see if Couenne is i...