[Scip] problems with solving LPs

Stefan Heinz heinz at zib.de
Mon Aug 31 10:38:24 MEST 2009


Hi Frank,

my first question is which LP solver did you link to SCIP?

On the other hand there is Bug in SCIP Version 1.1 with respect to the  
objective limits for the LP solver.


Best Stefan

Am Freitag 28 August 2009 schrieb Frank Hennig:
> Hi,
>
>
>
> I run a Branch-and-Price algorithm that solves very many LPs in its
> nodes.
>
>
>
> Unfortunatelly I very often encounter the error message:
>
>
>
> src/scip/solve.c:670] ERROR: Error <-6> in function call
> [src/scip/solve.c:1812] ERROR: Error <-6> in function call
> [src/scip/solve.c:2443] ERROR: Error <-6> in function call
> [src/scip/solve.c:3018] ERROR: Error <-6> in function call
> [src/scip/scip.c:5221] ERROR: Error <-6> in function call
>
>
>
>
>
> which leads to abortion of the SCIPsolve routine.
>
>
>
> One possible reason is: [src/scip/lp.c:10772] debug: unresolved error
> while resolving LP in order to exceed the objlimit
>
>
>
>
>
> The errors like to occur in the SCIP heuristics (preferably diving) but
> also during solving a node.
>
>
>
>
>
> Is their any chance to improve the performance?
>
>
>
>
>
> This costs time and also may lead to random solvability.
>
>
>
>
>
> Thank you very much.
>
>
>
> Regards,
>
>
>
> Frank
>
>
>
>
>
>
>
> ________________________________________________________
>
>
>
> Frank Hennig  -  Naval Architect, PhD Candidate
>
>
>
> Department of Industrial Economics and Technology Management
>
> Norwegian University of Science and Technology
>
> Alfred Getz veg 3
>
> NO-7491 Trondheim, Norway
>
>
>
> Phone:   +49 30 314 23 598
>
> Email:      frank.hennig at iot.ntnu.no




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