Search found 39 matches

by abb.omidi
3 months ago
Forum: API
Topic: GAMSPy issues
Replies: 2
Views: 6363

Re: GAMSPy issues

Dear Muhammet,

Thank you so much for your detailed explanation.
I will check that and get back to you if I have any issues.

Best regards
Abbas
by abb.omidi
4 months ago
Forum: API
Topic: GAMSPy issues
Replies: 2
Views: 6363

GAMSPy issues

Dear support team, First, thank you so much for developing and supporting such a nice tool that works as easily as GAMS Studio. I am trying to implement and run a tiny example, a simple transportation model, to see how this new feature works. Let's say, I have frequently used Google Colab. 1) When I...
by abb.omidi
1 year ago
Forum: Modeling
Topic: Converting an assignment into the schedule
Replies: 0
Views: 2858

Converting an assignment into the schedule

Dear support team, I am working on an assignment problem in which the output would be of assigning tasks to the resources w.r.t minimizing the number of resources. Suppose the following output: m1 m2 m3 m4 item1 1.000 item2 1.000 item3 1.000 item4 1.000 item5 1.000 item6 1.000 item7 1.000 item8 1.00...
by abb.omidi
1 year ago
Forum: Modeling
Topic: Is it possible to use a decision variable as an outer loop (combination)
Replies: 2
Views: 1543

Re: Is it possible to use a decision variable as an outer loop (combination)

Dear Dr. Bussieck,

Many thanks for your answer. The second paragraph you mentioned is exactly what we were looking for. Now, it is clear to us.

Best regards
Abbas
by abb.omidi
1 year ago
Forum: Modeling
Topic: Is it possible to use a decision variable as an outer loop (combination)
Replies: 2
Views: 1543

Is it possible to use a decision variable as an outer loop (combination)

Hi, There are some situations in which one needs to use a decision variable as an index in a specific constraint. Applying such a case, somewhat, is straightforward by introducing the auxiliary binary variables and adding appropriate constraints. Now, someone needs to use a decision variable as an i...
by abb.omidi
2 years ago
Forum: Modeling
Topic: Lagrangian relaxation issue
Replies: 1
Views: 1570

Re: Lagrangian relaxation issue

Dear community team,

If you need more details about the question I can elaborate more on this. Actually, I do not expect an exact answer and any useful insight would be appreciated.

Best regards
Abbas
by abb.omidi
2 years ago
Forum: Modeling
Topic: Lagrangian relaxation issue
Replies: 1
Views: 1570

Lagrangian relaxation issue

LR_(GAP-2)_1.gms Dear community team, I am trying to solve a scheduling problem by using the Lagrangian relaxation method. As I am pretty new in this field have tried to start with a generalized assignment problem to understand how this method can work on the MILP's. Also, I have read https://my.ec...
by abb.omidi
2 years ago
Forum: Modeling
Topic: Issue about fix and dive heuristic
Replies: 0
Views: 2825

Issue about fix and dive heuristic

Hi, I am trying to solve a scheduling problem (MILP) by using GAMS/Cplex. As the problem is not being solved in a reasonable time for the large-scale instance, I would like to use a simple heuristic namely fix and dive to achieve a feasible solution. What I have tried to do is, solving the original ...
by abb.omidi
2 years ago
Forum: Modeling
Topic: Issue on executing an option file
Replies: 0
Views: 1895

Issue on executing an option file

Dear community team, I am trying to solve an NLP problem by using Baron solver via the Neos interface in the GAMS v.34. The option file contains two local parameters of the Baron solver and is as follows: option nlp= Baron; $onecho > baron.opt numloc 0 dolocal 0 $offecho model.optfile=1; When I have...
by abb.omidi
3 years ago
Forum: Modeling
Topic: Defining the planning horizon in the RCPSP
Replies: 0
Views: 2068

Defining the planning horizon in the RCPSP

Dear support team, I am trying to write an optimization model related to the resource-constrained project schedule based on Pritsker et al. formulation. The model is as follows: test.jpg When I have defined the objective function as shown in the model, the final solution is incorrect but, when I wri...