[Scip] Branch-Price to Branch-cut-Price

[Ambros Gleixner]

Dear Cristina,

as far as I know, you cannot call separators before pricing.  However, 
you can implement the CONSINITLP callback of a constraint handler, which 
can add cutting planes during the pricing loop.

Maybe you can describe a bit better what you want to do exactly.  Would 
you want to cut off already the suboptimal LP solutions during the 
pricing loops (is that possible?) or add cutting planes that are 
independent of the solution?

Cheers,
Ambros



Am 06.06.2014 19:30, schrieb Cristina Núñez del Toro:
> Dear Mailing List,
>
> I am currently working on a Branch-and-Price algorithm. My next step is
> to strength the LP relaxation at nodes, so I implemented a plug-in
> separator in order to add cutting planes. My idea is to add cutting
> planes before start looking for new columns.
>
> However, I have noticed that at each node, the variable pricer plug-in
> is executed in the first place and then, when no more columns are added,
> the separator plug-in starts. Is there a way to change the order of the
> plug-in's execution? i.e., start first with the separator and then, when
> no more cuts can be added, execute the variable pricer? Maybe I am
> leaving outa callback ?
> Thanks in advance.
>
> --
> ---
> Cristina Nuñez
>
>
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-- 
____________________________________________________________
Ambros M. Gleixner
Zuse Institute Berlin - Matheon - Berlin Mathematical School
http://www.zib.de/gleixner