Search found 108 matches
- 7 years ago
- Forum: Solvers
- Topic: CPLEX stuck "Removing shift" on MILP
- Replies: 3
- Views: 5307
Re: CPLEX stuck "Removing shift" on MILP
Steve: Thanks for your reply, we will see if we can manage the time to get this to a reproducible case but I'm guessing this will be difficult since its a very hard problem and solve takes very long so it will be hard to pinpoint the problem. I'm sorry for my conceptual mixup. I had misunderstood th...
- 7 years ago
- Forum: Solvers
- Topic: Problems with the initial point
- Replies: 4
- Views: 6770
Re: Problems with the initial point
This is the expected behaviour, as far as I understand. From http://www.gams.com/latest/docs/userguides/userguide/_u_g__tutorial.html : "The default initial level is zero unless zero is not within the bounded range, in which case it is the bound closest to zero" This is of course not conve...
- 7 years ago
- Forum: Solvers
- Topic: CPLEX stuck "Removing shift" on MILP
- Replies: 3
- Views: 5307
CPLEX stuck "Removing shift" on MILP
Hi all. We are trying to solve a MILP, but a particular instance gets consistently stuck at a point in the solve. Looking at the detailed log we can see that the process is stuck while performing the "Removing shift" step after achieving dual infeasibility for the node. It just keeps writi...
- 7 years ago
- Forum: Solvers
- Topic: Problem with the Model status with Antigone solver
- Replies: 9
- Views: 10101
Re: Problem with the Model status with Antigone solver
Good to know. Thanks!
- 7 years ago
- Forum: Solvers
- Topic: Problem with the Model status with Antigone solver
- Replies: 9
- Views: 10101
Re: Problem with the Model status with Antigone solver
As I understand, there is no other possible model status for GAMS after a succesful solve for an NLP that a local optimum. The GAMS manual explicitly mentions this in http://www.gams.com/latest/docs/userguides/mccarl/modelstat_tmodstat.htm I'm not a global optimization expert, so the real question f...
- 7 years ago
- Forum: Solvers
- Topic: BONMIN branch and bound
- Replies: 2
- Views: 4942
Re: BONMIN branch and bound
Thanks Michael, indeed most solvers have quite obscure logs. I would have to do the research but it seemed worth giving the new forums a shot for anyone familiarized with the math behind BONMIN. Nice to see gamsworld back, btw !
Regards!
Claudio
Regards!
Claudio
- 7 years ago
- Forum: Tools
- Topic: Saving solution with partial solve, and restarting solve
- Replies: 2
- Views: 4937
Re: Saving solution with partial solve, and restarting solve
Setting:
option reslim=600
Will make the solver stop after 10 minutes. You can also consider iterlim for a stopping based on the number of iterations.
http://www.gams.com/latest/docs/usergui ... eslim2.htm
http://www.gams.com/latest/docs/usergui ... terlim.htm
Regards!
Claudio
option reslim=600
Will make the solver stop after 10 minutes. You can also consider iterlim for a stopping based on the number of iterations.
http://www.gams.com/latest/docs/usergui ... eslim2.htm
http://www.gams.com/latest/docs/usergui ... terlim.htm
Regards!
Claudio
- 7 years ago
- Forum: Solvers
- Topic: BONMIN branch and bound
- Replies: 2
- Views: 4942
BONMIN branch and bound
Hi all, I am now trying BONMIN on a MINLP, chose to began with B&B just for the fun of "watching" the tree grow :) . I don't understand the following process I'm seeing in the solver log: As you can see there seems to be reports of two different kinds NLPs being run, which I marked in ...