Search found 39 matches
- 3 years ago
- Forum: Modeling
- Topic: Issue with the reformulating MINLP
- Replies: 0
- Views: 1942
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...
- 3 years ago
- Forum: Modeling
- Topic: Solving MIP using MCP
- Replies: 0
- Views: 1770
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 ...
- 4 years ago
- Forum: Modeling
- Topic: Implementing decomposition method
- Replies: 2
- Views: 2171
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
- 4 years ago
- Forum: Modeling
- Topic: Implementing decomposition method
- Replies: 2
- Views: 2171
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...
- 4 years ago
- Forum: Modeling
- Topic: GAMS Kestrel Issue
- Replies: 3
- Views: 4863
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...
- 4 years ago
- Forum: Modeling
- Topic: GAMS Kestrel Issue
- Replies: 3
- Views: 4863
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...
- 4 years ago
- Forum: Modeling
- Topic: Special constraint formulation
- Replies: 0
- Views: 1911
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...
- 4 years ago
- Forum: Modeling
- Topic: How to execute a warm start using GAMS/Cplex
- Replies: 0
- Views: 2312
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...
- 4 years ago
- Forum: Modeling
- Topic: GAMS/convert solver
- Replies: 2
- Views: 2736
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
- 4 years ago
- Forum: Modeling
- Topic: GAMS/convert solver
- Replies: 2
- Views: 2736
GAMS/convert solver
Dear community, I have tried to use convert facility to write a (.MPS) file from an NLP solver. The code is as follows: model Mark_cut / all /; *** Modifications * choose convert as solver option nlp = convert; ** write convert option file $echo fixedmps Mark_cut.mps > convert.opt ** instruct conver...