[Scip] add constraints while solver is running?

[Ambros Gleixner]

I just realized: Maybe your question was more about how to interrupt the 
solving process in order to communicate the new upper bound.

For this, using the event handler system of SCIP is probably best, see

    http://scip.zib.de/doc/html/EVENT.shtml

Maybe check out how it's done in the code of our parallelization 
framework UG, which is included in the SCIP Optimization Suite.

- Ambros



Am 29.03.2013 21:23, schrieb Ambros Gleixner:
> Hi Sandy,
>
> both local and global constraints can be created and added during the
> solution process as usual via SCIPcreateCons...() and SCIPaddCons().
>
> However, you do not have to/should not add the upper bound as a
> constraint, but can use the parameter "limits/objective"; this can be
> changed at any time during the solution process via
>
>     SCIP_CALL( SCIPsetRealParam(scip, "limits/objective", value) );
>
> Also, you might consider transferring the solutions themselves via
> SCIPtrySol() or SCIPaddSol() because this can improve the performance of
> some primal heuristics; but then again the solution from one subproblem
> may not be feasible for the others and hence be rejected.
>
> Hope this helps,
>
> Ambros
>
>
>
>
> Am 29.03.2013 19:25, schrieb Sandy Ryza:
>> Hi All,
>>
>> Is there an easy way in SCIP to add constraints while the solver is
>> running?  My use case is that I want to try running multiple solvers in
>> parallel on different subproblems, and if one of the solvers comes
>> across a good solution I want to be able to set the upper bound on the
>> other ones for better pruning.
>>
>> thanks for any guidance,
>> Sandy
>>
>>
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>>
>

-- 
____________________________________________________________
Ambros M. Gleixner
Zuse Institute Berlin - Matheon - Berlin Mathematical School
http://www.zib.de/gleixner