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

[Cristina Núñez del Toro]

Hello Ambros,

My idea is to cutt off already the suboptimal LP solutions just before the
pricing loop starts. What I want is to strengthen the LP solution before
looking for new columns. However, doing it during the pricing loop may help
as well.  I will try the CONSINITLP callback.

Thank you.



2014-06-11 19:40 GMT+02:00 Ambros Gleixner <gleixner at zib.de>:

> 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
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-- 
---
Cristina Nuñez
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