[Scip] Dive

[Jonas Witt]

Hi Ambos,

thanks for your help, I will try to implement the SCIPaddColDive() function.

I have another question:
I have a SCIP instance in SCIP_STAGE_PROBLEM and I just want to 
construct the root lp (without solving it) to start a dive. How can I do 
this?

I tried to turn presolving off and set lp/iterlim as well as 
limits/nodes to 0 (I also tried 1). Then I called SCIPsolve(), but it 
sometimes still solved the SCIP instance or left the SCIPsolve() in 
SCIP_STAGE_PRESOLVING. After the dive I would like to return to the 
SCIP_STAGE_PROBLEM, because I need to solve and modify this problem later.


Best regards,
Jonas



Am 06.05.2013 15:02, schrieb Ambros Gleixner:
> Hi Jonas,
>
> yes, this is possible.  I cannot think of any big problems.  The most
> important issue is that the already existing columns are not modified
> (except for bounds and objective coefficients, of course) and that the
> LP is shrunk to the initial size when calling SCIPendDive().  This
> should be completely parallel to SCIPaddRowDive().
>
> I do not see another possibility except for expensive ways such as using
> a sub-SCIP.
>
> You can ask me any questions if you run into problems during the
> implementation.  We would be happy to include such an extension into the
> next release.
>
> Ambros
>
>
> Am 06.05.2013 10:03, schrieb Jonas Witt:
>> Hi all,
>>
>> I use the diving mode and I would like to add columns to the diving lp.
>> Is it possible to write a SCIPaddColDive()-function which is similar to
>> the SCIPaddRowDive()-function? What problems might occur? Or is there
>> another possibility to do this?
>>
>> Best regards,
>> Jonas
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