[SCIP] Creating a new Branching Rule in SCIP

[Matheus Ota]

Hi Leon,

Thanks for your detailed answer! Yes, I want to query if the lower bound of
the variable equals the upper bound, and what is this value.

Thanks again,
Matheus

Em ter., 26 de mai. de 2020 às 04:57, Leon Eifler <eifler at zib.de> escreveu:

> Hello Matheus,
>
> everything you want to achieve can be implemented in a branching rule. I
> don't think there is a benefit of doing this in a constraint handler. In
> your branching rule you can create to child nodes and add all bound
> changes that you want to do for S and T to those child nodes.
>
> > Also, in order to select the sets S and T I also need to know all the
> > variables already fixed to 0 and to 1. Is there any way of doing this?
> > Should I store all the variables fixed in each branching in a data
> > structure? Or there is an easier way of just checking if the variable
> > is already fixed or not?
>
> You can get all fractional variables by calling SCIPgetLPBranchCands (or
> do you think of fixed as in local lower bound equals local upper bound?)
>
> > Also, my idea for branching is not enough to separate all fractional
> > solutions. So when it is not possible to use my branching, I want SCIP
> > to use the branching it normally uses (I guess it is strong
> > branching). Could anyone that knows about this give me some help here?
>
> You do not have to do anything here. If you give your branching rule a
> high priority it will get called first. Just ensure that your branching
> rule sets the result pointer to SCIP_DIDNOTFIND or SCIP_DIDNOTRUN
> (whichever makes more sense) if it does not find a branching. Then the
> branching rule with the next hightest priority will get called.
>
> Best,
> Leon
>
>
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