[Scip] questions on GUB cut of SCIP

[Thorsten Koch]

Dear Jinghui,

we are currently working on GUB covers and they will be
included as "experimental" in the next release.

Best regards,
Thorsten

Am 24.03.2010 11:53, schrieb Tobias Achterberg:
> Hi Jinghui,
> 
> sorry to answer so late, I am really busy these days...
> 
> As far as I know, there is still no GUB cover cut in SCIP. There is a corresponding code
> in the presolving methods of the knapsack constraint hander, but not in the separation
> procedures.
> 
> The way to integrate this separator would be to extend the cut separation procedures in
> cons_knapsack.c. You should ask the SCIP development team (which I am no longer a member
> of), in this case Kati Wolter (wolter at zib.de), how to proceed.
> 
> Regarding your second question, the answer is "yes". It should be pretty easy to include
> your primal heuristic. I don't know exactly what you mean with "variable reduction".
> Variable selection rules for branching as well as presolving methods can be added easily
> to SCIP.
> 
> 
> Tobias
> 
> 
> Jinghui Zhang wrote:
>> Dear Dr Tobias,
>>
>> Sorry for distrubing you for questions on SCIP.
>>
>> I am gonna implement a customized branch and cut algorithm based on the
>> existing branch and cut framework implementations. After reading a few
>> survey papers and relevant working papers by you and your colleagues at
>> ZIB, I realize SCIP probably will be a good candidate
>> for adpating my customized branch and cut procedure.
>>
>> However, since my branch and cut procedure relies heavily on Generalized
>> Upper Bound cut, which seems currently not found in SCIP framework, I am curious about that how GUB cut
>> procedure can be integrated into SCIP. As far as I know, in open
>> source software Minto and commercial software CPLEX, XPRESS-MP, GUB cut
>> is implemented and adopted as default cut generation options.
>>
>> To summrize, my questions are as follows:
>> 1) is there a default GUB cut procedure within SCIP? If not, what's
>> the easiest way to integrate GUB cut into SCIP.
>> 2) is it easy to adapt my customized primal heuristics and variable reduction into SCIP?
>>
>> I am looking forward for your reply!
>>
>> Cheers,
>> Jinghui
>>
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-- 
The important thing is not to stop questioning.
Curiosity has its own reason for existing.          -- Albert Einstein
______________________________________________________________________
Dr. Thorsten Koch / Konrad-Zuse-Zentrum für Informationstechnik Berlin
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koch at zib.de     /                     Phone +49-30-84185-213, Fax -269
_______________/  DFG Research Center "Matheon"  http://www.matheon.de

Kooperativer Bibliotheksverbund Berlin Brandenburg  http://www.kobv.de
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