[Scip] How to update separators in a branch-price-and-cut?

[Gerald Gamrath]

Hi Nikolaj,

> I would like to be able to adapt the settings w.r.t the cuts, i.e. I would
> like to have different behavior among the different cuts (a certain value
> for the efficacy of cut1, another value for the efficacy of cut2. If I'm
> not wrong, this is not possible with SCIP).
>   

Yes, your right, that is not possible with SCIP, if you really need it,
you have to use the workarounds discussed before.
> I will try to use the rowage parameter to force cuts out.
>
> Here is my question: when I want to update a cut (add the new variables
> generated by the pricer), how can I be sure that this cut is still active
> (i.e. still considered by SCIP to be useful even if not used in the
> current LP).
>   

You can check with SCIProwIsInLP() whether the cut is still in the LP.
If it is not in the LP, then I think it was deleted and is not
considered by SCIP anymore. However, as far as I know, cuts may only be
deleted at the node where they were created, so if that is not the case,
they remain in the LP for the whole solving process.

By the way: Do you want to generate cuts only at the root node or also
during the branch-and-bound search?

Best,
Gerald