Search found 15 matches

by abb.omidi
1 month ago
Forum: API
Topic: Read a MPS/LP file in Java
Replies: 0
Views: 152

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
1 month ago
Forum: Modeling
Topic: Using SOS type_1 constraint
Replies: 2
Views: 128

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
1 month ago
Forum: Modeling
Topic: Using SOS type_1 constraint
Replies: 2
Views: 128

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
2 months ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 225

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
2 months ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 225

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 GUROBI or CPLE...
by abb.omidi
2 months ago
Forum: Modeling
Topic: Lazy constraints
Replies: 4
Views: 225

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
by abb.omidi
9 months ago
Forum: Modeling
Topic: flexible job shop scheduling
Replies: 1
Views: 388

Re: flexible job shop scheduling

hello According to the model, you can use from a table (or parameter) to define model data. For example, you may have a process time parameter (time of operation of jobs) or a route parameter (binary parameter: 1 if the operation of j pressed before operation of i in machine k, otherwise 0) that dep...
by abb.omidi
9 months ago
Forum: Modeling
Topic: Logical constraint
Replies: 0
Views: 614

Logical constraint

Hello everybody I have a question about coding logical constraint in the GAMS IDE. Please, let me describe optimization model: { set i /1*2/; parameter cost(i); integer variable nb(i); .... of.. obj =e= sum(i,cost(i)*nb(i))+(x-1)*500; con1.. sum(i,nb(i)*ns(i)) =g= N; } There is a logical constraint ...
by abb.omidi
1 year ago
Forum: Modeling
Topic: solving a model with deferent solvers
Replies: 5
Views: 662

Re: solving a model with deferent solvers

Dear Fred

Thanks for your replay.
Please let me describe my problem. I want to solve my model with three deferent solvers using for loop. I coded it with for statement but I want to know, do exist the better way to code it?

Best regards
by abb.omidi
1 year ago
Forum: Modeling
Topic: solving a model with deferent solvers
Replies: 5
Views: 662

Re: solving a model with deferent solvers

Hello
Thanks for your reply.
My means that, have a specific syntax for write easy or better this subject?
(For example I know that, optfile syntax can replace with option=solver.name)

Best regards