[Bonmin] Infeasibility

[Kanika Dhyani]

Hi Claudia,

The thing is that I have some subproblems and which are LPs and MINLP for
which I alternate between CPLEX and BONMIN. I am using BB-B for these
problems. It is strange as to why I would get these infeasibility errors due
to upgrade of CPLEX, but that is the only thing that has changed.

Regards,
Kanika

-----Original Message-----
From: Claudia D'Ambrosio [mailto:c.dambrosio at unibo.it] 
Sent: giovedì 17 luglio 2008 15.50
To: bonmin at list.coin-or.org
Cc: Kanika Dhyani
Subject: Re: [Bonmin] Infeasibility

Hi Kanika,
which Bonmin algorithm are you using?
For non convex MINLPs I use B-BB and in this case, to my knowledge, Cplex is

not involved in the run (it is just used in B-OA and B-Hyb algorithms as
MILP 
subsolver). 
If you do not use B-BB for non-convex problem, some Outer Approximations
cuts 
might cut off (part of) your feasible region.
Regards,
Claudia




On Wednesday 16 July 2008 04:56:23 pm Kanika Dhyani wrote:
> Hi,
>
> I am tackling a mixed integer nonlinear non convex program . My problems
> started after the upgrade of the licenses on our server. I am using BONMIN
> and CPLEX with AMPL in the same problem. We upgraded the CPLEX licenses to
> 11. Following which all my codes which used BONMIN now tell me that the
> problem is infeasible and dont work now. Earlier they all worked perfectly
> fine.
>
> Playing with some settings I get either Infeasible Problem or Ipopt
exceeds
> maximum number of iterations or problem too expensive. Please advice.
>
> Thank you
> Kanika