Search found 384 matches

by bussieck
1 day ago
Forum: Syntax
Topic: Positive variable
Replies: 1
Views: 52

Re: Positive variable

Have you checked the model and solve status? Perhaps, the solver did not give you a feasible solution: S O L V E S U M M A R Y MODEL transport OBJECTIVE z TYPE LP DIRECTION MINIMIZE SOLVER CPLEX FROM LINE 65 **** SOLVER STATUS 1 Normal Completion **** MODEL STATUS 4 Infeasible **** OBJECTIVE VALUE 2...
by bussieck
1 day ago
Forum: Modeling
Topic: Variable definition
Replies: 5
Views: 70

Re: Variable definition

Tim,

Integer variables come by default with an upper bound of 100. See https://www.gams.com/latest/docs/UG_Lan ... rVariables and also for the ways around this, e.g. "option intvarup=0;"

Hope this helps,
-Michael
by bussieck
4 days ago
Forum: Solvers
Topic: gams2prm.gms
Replies: 4
Views: 697

Re: gams2prm.gms

It's part of Tom Rutherford's GAMS collection: http://www.mpsge.org/inclib/gams2txt.htm#gams2PRM. There are installation instructions at the top of the page.

-Michael
by bussieck
4 days ago
Forum: Syntax
Topic: Spaces in file path
Replies: 2
Views: 515

Re: Spaces in file path

execute (as $call) calls the shell of the system. Do what you need to do to protect the spaces. For example:

Code: Select all

execute 'gams "Path To File/SubFile1.gms" r=wf1 %ide%'  ;
-Michael
by bussieck
1 week ago
Forum: Syntax
Topic: define Sets in ALM problem
Replies: 2
Views: 672

Re: define Sets in ALM problem

You t set isn't order. Without seeing the entire GAMS model it is hard to suggest something. Ordering of sets can be subtle in GAMS. General advice: Declare and define the sets you need ordered first in your GAMS model.

-Michael
by bussieck
1 week ago
Forum: Syntax
Topic: Disjunctive Programming by GAMS
Replies: 3
Views: 137

Re: Disjunctive Programming by GAMS

I suggest really reading the section, then you easily find "ELSEIF". -Michael
by bussieck
2 weeks ago
Forum: Modeling
Topic: can anyone help me remove subtour tsp?
Replies: 2
Views: 193

Re: can anyone help me remove subtour tsp?

Check out the TSP examples in the GAMS Model Library. Go to https://www.gams.com/latest/gamslib_ml/ ... ml#gamslib and filter for "tsp".

-Michael
by bussieck
2 weeks ago
Forum: Modeling
Topic: Shadow prices on binding constraints
Replies: 3
Views: 190

Re: Shadow prices on binding constraints

1) Yes. Look for EPS as a marginal. So if you have a non-basic (slack) variable with zero marginal. I like the description at https://glossary.informs.org/indexVer1.php?page=D.html 2) That you have multiple dual optimal solutions. A very natural thing especially for larger real world models (there i...
by bussieck
2 weeks ago
Forum: Modeling
Topic: Shadow prices on binding constraints
Replies: 3
Views: 190

Re: Shadow prices on binding constraints

Your model is dual degenerate, i.e. you have multiple dual solutions. Select different solvers and you (might) get different dual solutions. Both dual solutions are just fine: BDMLP: ---- EQU emissionCap LOWER LEVEL UPPER MARGINAL 1 -11.0000 -10.0000 +INF . 2 -10.0000 -10.0000 +INF 3.0000 3 -9.0000 ...