Search found 39 matches

by abb.omidi
4 years ago
Forum: Tools
Topic: Get a MPS file using NEOS/GAMS web interface
Replies: 1
Views: 3144

Get a MPS file using NEOS/GAMS web interface

Dear community team, I'm trying to use Neos/GAMS to solve an optimization problem. I will need to get a MPS file from the model. With using GAMS IDE it is easy to use an option file to get it but, it needs a licence file for large models. My question is, is there any way to get an MPS file using the...
by abb.omidi
4 years ago
Forum: Modeling
Topic: Connecting GAMS 28.1.0 to neos server
Replies: 3
Views: 3311

Re: Connecting GAMS 28.1.0 to neos server

Dear Fred, Thanks for your comment. I was trying to solve the attached example using GAMS/Kestrel via GAMS studio 28.1.0. When I solve the model log file is as follows: --- Job GAMS..Kestrel.gms Start 08/20/19 10:29:58 28.1.0 r5b48834 WEX-WEI x86 64bit/MS Windows --- GAMS Parameters defined Input C:...
by abb.omidi
4 years ago
Forum: Modeling
Topic: Connecting GAMS 28.1.0 to neos server
Replies: 3
Views: 3311

Connecting GAMS 28.1.0 to neos server

Dear support team, I'm trying to run the GAMS model using neos-server. I wrote the following code in the GAMS studio: Option mip=kestrel; sequence.optfile=1; $onecho > kestrel.opt kestrel_solver cplex neos_server www.neos-server.org:3333 $offecho But it doesn't work. I was wondering if, how can I co...
by abb.omidi
4 years ago
Forum: Modeling
Topic: Modeling the chance constraints
Replies: 0
Views: 1840

Modeling the chance constraints

Hello support team, I have worked on the MIP model that contains the chance constraints. The constraint is: probability_cons.. prob[sum(j, a(j)*x(j)) =l= b] =g= beta; Where a(j) and b are given parameters and beta is the probability. I was wondering if, you say that, is there any efficient way to wr...
by abb.omidi
4 years ago
Forum: API
Topic: Read a MPS/LP file in Java
Replies: 1
Views: 3723

Read a MPS/LP file in Java

Hello support team,

Would you please, say that is there any way (or any example) to read an "MPS/LP" file in the GAMS Java API and get output in the specific format? If so, could you advise me, please?

Regards
Omidi. A
by abb.omidi
4 years ago
Forum: Modeling
Topic: Using SOS type_1 constraint
Replies: 2
Views: 2653

Re: Using SOS type_1 constraint

Dear Fred, Thanks for your useful comment. As per your advice, I try to use a medium scale problem using both binary and SOS1 variables. The results and solving time are the same. I think using of SOS1 does not improve solving time (in my problem). Unfortunately, I can not understand why GUROBI (Jav...
by abb.omidi
4 years ago
Forum: Modeling
Topic: Using SOS type_1 constraint
Replies: 2
Views: 2653

Using SOS type_1 constraint

Dear support team, I was trying to solve a scheduling model using GAMS/Gurobi. The snippet code is: Binary variable x(i,k); Equations c1,c2; c1(k).. sum(i, x(i,k)) =e= 1; c2(i).. sum(k, x(i,k)) =e= 1; Using the binary variables, the model has solved optimally. I have used SOS type_1 variables instea...
by abb.omidi
5 years ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 4252

Re: Lazy constraints

Dear Fred,

Thanks so much for your help.
I can do it and it works fine.

Regards
Omidi. A
by abb.omidi
5 years ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 4252

Re: Lazy constraints

Dear Fred, Thanks for your replay. As per your comment, I try it and it works fine for cube problem while I try to run it on the "ROTDK" in the GAMS lib, it seems that it does not work properly. (it's solved optimally but did not apply any lazy constraint). AFAIK, to apply lazy in the GURO...
by abb.omidi
5 years ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 4252

Lazy constraints

Hello everybody,

Is there any way to use (or call) lazy constraint in GAMS modelling? If so, could you tell me how can I run it?

Thanks in advance
Omidi. A