Search found 53 matches

by bussieck
2 days ago
Forum: Syntax
Topic: Dimension Different Error
Replies: 3
Views: 62

Re: Dimension Different Error

Just define set i and make an alias(i,j).

Hope this helps,
-Michael
by bussieck
4 days ago
Forum: Syntax
Topic: Dimension Different Error
Replies: 3
Views: 62

Re: Dimension Different Error

Hi,

k is a label (string) not a number, so you can't multiply this with a variable. If the label happens to represent a number you can use k.val (see https://www.gams.com/latest/docs/UG_GAM ... ams_Labels)

Hope this helps,
- Michael
by bussieck
6 days ago
Forum: Announcements
Topic: GAMS Distribution 24.9.2 (Minor Release) Announcement
Replies: 0
Views: 24

GAMS Distribution 24.9.2 (Minor Release) Announcement

Hi GAMS Users,

We started distributing GAMS Release 24.9.2 on November 14, 2017. This is a maintenance release.

You can download the software from https://www.gams.com/download/

Here are the release notes:
https://www.gams.com/latest/docs/RN_249.html

-Michael
by bussieck
1 month ago
Forum: Solvers
Topic: Computational time of model extremely increased
Replies: 8
Views: 258

Re: Computational time of model extremely increased

GAMS/Cplex (in default mode) runs deterministically when executed on the identical model instance on the same machine. There are a few options that can make it behave non-deterministically (only with option thread<>1). But even slight changes (e.g. the order of variables and equations, or a coeffici...
by bussieck
1 month ago
Forum: Solvers
Topic: how to reduce memory use of cplex
Replies: 3
Views: 421

Re: how to reduce memory use of cplex

It is not Cplex that runs out of memory, it is GAMS. You can try to clear some unset large parameters (option clear=sym;) but Cplex will most likely require a multiple of the memory used by GAMS. So rent a bigger machine. There are plenty of cloud offering that give you access to machines with plent...
by bussieck
2 months ago
Forum: Modeling
Topic: Simple Equilibrium problem with non-linear equations - division by zero
Replies: 2
Views: 135

Re: Simple Equilibrium problem with non-linear equations - division by zero

I think the GAMS error messages are quite useful: **** Exec Error at line 6: division by zero (0) Line 6 reads: 6 demand.. qd =e= beta/(p**ed) ; GAMS variables have there default level at 0. So move p.l away from 0: p.l=1; Next you get: **** Unmatched variable not free or fixed qs Qs is a positive v...
by bussieck
2 months ago
Forum: Modeling
Topic: Problem with ignoring GAMS constraints
Replies: 4
Views: 141

Re: Problem with ignoring GAMS constraints

Did you check the model/solve status before you report things back to Excel? The solver might have told you that the model is (locally) infeasible.

-Michael
by bussieck
2 months ago
Forum: Solvers
Topic: CPLEX time vs resUsd
Replies: 6
Views: 227

Re: CPLEX time vs resUsd

The resUsd includes time to set up the model in Cplex and to report the solution to GAMS. For quadratic models it also included the time to extract the Q matrices from the non-linear instructions. Usually the time between resUsd and the time Cplex reports in the log is small and of not much practica...
by bussieck
2 months ago
Forum: Syntax
Topic: excel to gams
Replies: 9
Views: 409

Re: excel to gams

If you look at the content of the GDX file it will be pretty obvious that the read did not succeed as you planned: C:\Users\Michael\Downloads>gdxdump Daten-TSP.gdx $onempty Parameter d(*,*) / 'j2'.'0' 8.9, 'j2'.'2.2' 9.3, 'j2'.'1.8' 10.5, 'j2'.'10.1' 11.4, 'j2'.'0.6' 8.6, 'j3'.'0' 2.3, ... Problem i...
by bussieck
2 months ago
Forum: Syntax
Topic: excel to gams
Replies: 9
Views: 409

Re: excel to gams

You should check the return code after a $call and you should load data with $loadDC to make sure that you don't leave record behind. $call GDXXRW.exe Daten-TSP.xlsx trace=3 par=d rng=Tabelle1!A2 rdim=1 cdim=1 $if errorlevel 1 $abort problems with gdxxrw $GDXIN Daten-TSP.gdx $LOADDC d Hope this help...