Search found 30 matches
- 15 hours ago
- Forum: Modeling
- Topic: Defining the planning horizon in the RCPSP
- Replies: 0
- Views: 21
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...
- 2 weeks ago
- Forum: Modeling
- Topic: Issue with the reformulating MINLP
- Replies: 0
- Views: 87
Issue with the reformulating MINLP
Dear support team, I have tried to solve an optimization problem (an MINLP) to minimize the number of items that need to be stored. The objective function is as follows: objective function: Minimize z = sum(i, R(i)/x(i)) Where, R(i), i in {1, ..., n}, given constant and x(i) are integer variables. I...
- 8 months ago
- Forum: Modeling
- Topic: Solving MIP using MCP
- Replies: 0
- Views: 607
Solving MIP using MCP
Dear community team, I'm trying to solve a BIP using MCP solver. When I run the problem I have the following issue: Discrete variables can only appear in MIP, RMIP, MINLP, RMINLP, MIQCP or RMIQCP MPEC RMPEC problems. I was wondering if, A) Is it possible to use MCP solver for BIP/MIP? B) I'm trying ...
- 11 months ago
- Forum: Modeling
- Topic: Implementing decomposition method
- Replies: 2
- Views: 577
Re: Implementing decomposition method
Dear Dr Bussieck,
Many thanks for your suggestion.
As I'm not any experience in the graph colouring and I am interested in scheduling model, I'm wondering if, are there any related materials for the scheduling problems?
Regards
Omidi
Many thanks for your suggestion.
As I'm not any experience in the graph colouring and I am interested in scheduling model, I'm wondering if, are there any related materials for the scheduling problems?
Regards
Omidi
- 11 months ago
- Forum: Modeling
- Topic: Implementing decomposition method
- Replies: 2
- Views: 577
Implementing decomposition method
Dear support team, I have often used GAMS and now have tried to implement a Dantzig-Wolfe Decomposition for an LP problem. It works fine for a small instance. Now, I'm trying to extend the DW-based algorithm to solve the MIP model. I'm aware that some of the algorithms like heuristic-based CG, can b...
- 11 months ago
- Forum: Modeling
- Topic: GAMS Kestrel Issue
- Replies: 3
- Views: 1213
Re: GAMS Kestrel Issue
Dear Dr Bussieck, Many thanks for your detailed explanations. The issue was fixed and the model was solved by the kestrel. I have another issue and I was wondering if, you could advise me about that. I have tried to solve a scheduling problem and regard to, the model is a large scale, I would like t...
- 11 months ago
- Forum: Modeling
- Topic: GAMS Kestrel Issue
- Replies: 3
- Views: 1213
GAMS Kestrel Issue
Dear support team, I tried to use GAMS and Kestrel a while and it worked fine. Recently, I downloaded the new GAMS version (30.1.0 re01a340 WEX-WEI x86 64bit/MS Windows) and I activated it by using a trial licence. Now, I'm trying to solve an optimization model using GAMS/Kestrel. When I run the GAM...
- 1 year ago
- Forum: Modeling
- Topic: Special constraint formulation
- Replies: 0
- Views: 1055
Special constraint formulation
Hello community team, I have tried to write a scheduling problem which has been described by Sousa and Wolsey in machine scheduling. I'm going to use two different approaches to write my code. First, using the special syntax into the constraint and second, create dynamic sets. The following code des...
- 1 year ago
- Forum: Modeling
- Topic: How to execute a warm start using GAMS/Cplex
- Replies: 0
- Views: 974
How to execute a warm start using GAMS/Cplex
Dear community team, I have tried to solve a scheduling model. I would like to use a warm start to solve my problem because The model takes much time to solve optimally even for a small set of given data. The model statistic and what I'm looking for are as follows. The original model, a small instan...
- 1 year ago
- Forum: Modeling
- Topic: GAMS/convert solver
- Replies: 2
- Views: 1222
Re: GAMS/convert solver
Dear Fred,
Thanks so much for your reply. Would you say, is there any way to get a (.MPS) like format from GAMS, please?
Regards
Abbas
Thanks so much for your reply. Would you say, is there any way to get a (.MPS) like format from GAMS, please?
Regards
Abbas