Search found 192 matches

by Fred
1 day ago
Forum: Syntax
Topic: problem with syntax of the equation
Replies: 15
Views: 1134

Re: problem with syntax of the equation

Hi,

You set a lower bound of 0.15 for d(n1 .n5):

Code: Select all

 d.lo(n,np)$a(n,np) = dmin;  
Hence, it cannot be zero.

I hope this helps!

Fred
by Fred
1 day ago
Forum: Syntax
Topic: Is there a way for GAMS interruption and re-run from where it lasted?
Replies: 5
Views: 75

Re: Is there a way for GAMS interruption and re-run from where it lasted?

You can find the info you need in the documentation: https://www.gams.com/latest/docs/UG_GamsCall.html#GAMSAOsavepoint https://www.gams.com/latest/docs/UG_GDX.html#UG_GDX_EXECUTION_EXECUTE_LOADPOINT Providing a start point to a MIP solver may require to set an extra solver option (see e.g. https://f...
by Fred
1 day ago
Forum: Syntax
Topic: Is there a way for GAMS interruption and re-run from where it lasted?
Replies: 5
Views: 75

Re: Is there a way for GAMS interruption and re-run from where it lasted?

Hi, it seems that you do not want to restart GAMS but a solver run. There is no way to do this. With savepoint you can conveniently store a solution in a gdx file. You could load that solution a a start point the next day but that does not mean that the solver just restarts from the state of second ...
by Fred
1 day ago
Forum: Syntax
Topic: Providing initial solution and reoptimizing
Replies: 3
Views: 82

Re: Providing initial solution and reoptimizing

Nikou,

Dropping fixed values for variables works as you describe it (reste lower/uooer bound).

For MIP solvers, to use a starting point, usually you have to set a corresponding solver option, see e.g. https://www.gams.com/latest/docs/S_CPLE ... EXmipstart

I hope this helps!

Fred
by Fred
2 days ago
Forum: Modeling
Topic: small number safely considered as zero
Replies: 1
Views: 47

Re: small number safely considered as zero

Hi, In Math Programming, strict inequalities (as in your condition X>0) make no sense. For more details see: https://support.gams.com/gams:formulate_a_constraint_with_a_condition Apart from that, I don't see how your single =g= constraint should force y=0 if x>0. Once you know "how much" greater tha...
by Fred
2 days ago
Forum: Modeling
Topic: Questions about the Results
Replies: 3
Views: 43

Re: Questions about the Results

Hi,

It seems that you may have forgotten to add the constraint total_arrival, in which TA occurs, to your model.

I hope this helps!

Fred
by Fred
2 days ago
Forum: Archive Google Group
Topic: Conopt time limit has reached
Replies: 2
Views: 50

Re: Conopt time limit has reached

Hi,

If you want to evaluate GAMS, I suggest to contact sales@gams.com to ask for a time limited evaluation license.

Best,
Fred
by Fred
2 days ago
Forum: API
Topic: pySetup=0
Replies: 1
Views: 45

Re: pySetup=0

Hi Renger,

pySetup is a command line parameter. Just add it to your GAMS call, e.g.

Code: Select all

gams myFile.gms pySetup=0
or in the corresponding fields of Studio/IDE.

I hope this helps!

Fred
by Fred
3 days ago
Forum: Archive Google Group
Topic: Conopt does not give me results for every equation
Replies: 1
Views: 49

Re: Conopt does not give me results for every equation

Could you please elaborate your problem? I don't understand what you mean with Conopt does not give me results for every equation?
Conopt seems to solve just fine when I run your model.

Best,
Fred
by Fred
3 days ago
Forum: Solvers
Topic: Infeasible, but optmal solution found
Replies: 1
Views: 54

Re: Infeasible, but optmal solution found

Hi,

You are looking at the equation listing (https://www.gams.com/latest/docs/UG_GAM ... ionListing) which is part of the model generation output. I.e. the infeasibiities you see refer to the provided start point.

I hope this helps!

Fred