Search found 48 matches

by bussieck
1 day ago
Forum: Modeling
Topic: Simple Equilibrium problem with non-linear equations - division by zero
Replies: 2
Views: 15

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 days ago
Forum: Modeling
Topic: Problem with ignoring GAMS constraints
Replies: 2
Views: 18

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 days ago
Forum: Solvers
Topic: CPLEX time vs resUsd
Replies: 2
Views: 15

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
5 days ago
Forum: Syntax
Topic: excel to gams Topic is solved
Replies: 8
Views: 187

Re: excel to gams Topic is solved

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
6 days ago
Forum: Syntax
Topic: excel to gams Topic is solved
Replies: 8
Views: 187

Re: excel to gams Topic is solved

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...
by bussieck
1 week ago
Forum: Modeling
Topic: Quadratic constrained convex problem Topic is solved
Replies: 2
Views: 39

Re: Quadratic constrained convex problem Topic is solved

Not sure what you mean. If I solve this with a global solver like Antigone, Baron, Couenne, LindoGlobal, or SCIP (since this is a non-convex QCP) I get a good solution: LOWER LEVEL UPPER MARGINAL ---- VAR OF -INF 4.472 +INF . ---- VAR x1 -INF 0.011 +INF . ---- VAR x2 -INF 4.472 +INF . Not sure what ...
by bussieck
1 week ago
Forum: Syntax
Topic: excel to gams Topic is solved
Replies: 8
Views: 187

Re: excel to gams Topic is solved

Hi, Writing to an open workbook is possible but very much discouraged. You need to share you workbook (see https://support.office.com/en-us/article/About-the-shared-workbook-feature-49b833c0-873b-48d8-8bf2-c1c59a628534). Problem is that you only see the changes after "saving" the open work...
by bussieck
2 weeks ago
Forum: Announcements
Topic: GAMS Distribution 24.9.1 Announcement
Replies: 0
Views: 56

GAMS Distribution 24.9.1 Announcement

Hi GAMS Users,

We started distributing GAMS Release 24.9.1 on August 30,2017

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
3 weeks ago
Forum: Modeling
Topic: load dimension are different Topic is solved
Replies: 4
Views: 86

Re: load dimension are different Topic is solved

Dt has three dimensions in the GDX file and you declare it as Dt(r) (one dimensional). Not sure what your intension is but this is where GAMS chokes. The symbol Dt comes two dimensional out of gdxxrw (rdim=1 cdim=1) and then you merge things together (with gdxmerge) which add another index position....
by bussieck
3 weeks ago
Forum: Modeling
Topic: load dimension are different Topic is solved
Replies: 4
Views: 86

Re: load dimension are different Topic is solved

Marina, You have declared the symbol in your GAMS program with a different number of dimensions than the symbol has in GDX. The following example has the same problem: set three(*,*,*) / 1.1.1, 2.2.2 /; $gdxOut three $unLoad three $gdxOut set two(*,*) $gdxIn three $load two=three gives: --- GDXin=C:...

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