[Scip] "Hidden" cut generators

Giacomo Nannicini giacomo.n at gmail.com
Thu Nov 22 17:29:22 MET 2012


Hi Stefan,
yes, that is indeed the case: the cuts come from constraint handlers.
I didn't know constraint handlers have a slightly different treatment.
Still familiarizing with the structure of the code.

Thanks!

Giacomo

On Fri, Nov 23, 2012 at 12:09 AM, Stefan Vigerske
<stefan at math.hu-berlin.de> wrote:
> Hi,
>
> happy to see you on this list :-).
>
> Constraint handlers also do separation, maybe that's where the cuts came
> from.
> Do you get any numbers in the "Cuts" column for constraint handler
> statistics?
> If not, just send then the full output of "display statistics".
>
> Best,
> Stefan
>
>
> On 11/22/2012 04:45 PM, Giacomo Nannicini wrote:
>>
>> Hi all,
>> I noticed a strange behavior in SCIP that makes me think there are
>> some "hidden" cut generators.
>>
>> I manually disabled *all* separators from scipdefplugin.c (I commented
>> out all lines with SCIPincludeSepa). No cut generators are listed in
>> SCIP when I use "set separating" or in the final "display statistics".
>> However, some cuts *are* generated. In some logs, I get a nonzero
>> number of cuts indicated, even though "display statistics" says that
>> there are no separators. Cut pool size stays at zero. Also, the
>> solution path is different from what I get if I set "set separating
>> maxroundsroot 0". With the latter setting, no cuts appear.
>>
>> Can somebody enlighten me?
>>
>> Thanks a lot!
>>
>> Giacomo
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>


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