[Scip] Tentative branching not working

nikolaj@crt.umontreal.ca nikolaj at crt.umontreal.ca
Tue Mar 31 22:52:30 MEST 2009


On Mon, March 30, 2009 4:37 am, Tobias Achterberg wrote:
> Hi Nikolaj,
>
>
> First of all, you need to pass SCIPgetLocalTransEstimate(scip) (or any
> reasonable estimate in terms of the *transformed* problem) to
> SCIPcreateChild(). This is also wrong in the
> coloring example, and it could be documented better in the
> SCIPcreateChild() call.
>
>
> SCIP Team: Please fix this!
>
>
>
> Your code is correct. If I understand correctly, the issue you are seeing
> is that in the LP relaxation of the child node, your constraint is not
> (yet) present.
>
>
> I think the problem is that you set
> (a) initial == FALSE in your SCIPcreateConsLinear() call, and
> (b) the separation frequency of the linear constraint handler to 0, which
> is the default value.
>
> Both using initial == TRUE and constraints/linear/sepafreq = 1 should fix
> your problem. Most probably, initial == TRUE is what you want.
>
>
>
> Best,
>
>
> Tobias
>
Hi Tobias,

Thank you very much for your quick answer. Setting initial == TRUE in the
SCIPcreateConsLinear() call and fixing parameter
constraints/linear/sepafreq = 1 works perfectly. I didn't understand the
setting initial == TRUE in the call.

Best regards,

Nikolaj







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