[Scip] Implementing new branching rule

[Siddhartha Jain]

Thanks. So just to recap,

SCIPgetLPBranchCands returns the variables of the transformed problem which
I can access via SCIPvarGetTransformed?

Also does the transformed problem change during the course of the search
after the initial preprocessing has been done?

--Sid


On Tue, Dec 18, 2012 at 4:53 PM, Timo Berthold <berthold at zib.de> wrote:

> Well, for each variable and constraint you can get its transformed:
> SCIP{var,cons}GetTransformed()
>
> You can easily look in the LP/var/cons section of scip.h and into
> pub_var.h, pub_cons.h, pub_lp.h to see whether the interface functions
> that you need is available there.
>
> Timo
>
> > Actually thinking a bit more, what I actually need is the transformed
> > problem constraints and the variables in each constraint. Is there a way
> > to
> > access those?
> >
> > Thanks
> > --Sid
> >
> >
> > On Tue, Dec 18, 2012 at 3:42 PM, Siddhartha Jain <sj1 at cs.cmu.edu> wrote:
> >
> >> Hi Timo,
> >>
> >> Thanks for the reply. It's a research idea that I'm implementing.
> >>
> >> If the variables returned are those of the transformed problem, is there
> >> a
> >> way for me to get the column index to which the variables correspond to?
> >>
> >> Thanks
> >> --Sid
> >>
> >>
> >> On Tue, Dec 18, 2012 at 3:16 PM, Timo Berthold <berthold at zib.de> wrote:
> >>
> >>> Hi Sid,
> >>>
> >>> this function gives you an array of SCIP_VAR pointers. These variables
> >>> are
> >>> variables in the transformed problem which have a fractional solution
> >>> in
> >>> the LP solution of the current node relaxation.
> >>>
> >>> If you want to get the variable's problem index, you can call the
> >>> function
> >>> SCIPvarGetProbindex() with these variable pointers as input.
> >>>
> >>> I am curious: what variant of strong branching do you plan to
> >>> implement?
> >>>
> >>> I recommend you to look through the full strong branching and maybe the
> >>> most fractional branching rule in SCIP to get an idea how they are set
> >>> up.
> >>>
> >>> If not yet happened, I further recommend you to have a look at the
> >>> following points in the SCIP documentation:
> >>> http://scip.zib.de/doc/html/BRANCH.shtml
> >>>
> >>>
> http://scip.zib.de/doc/html/scip_8h.shtml#a04924d1578c8b893f8420001445210fd
> >>>
> >>>
> http://scip.zib.de/doc/html/pub__var_8h.shtml#a661c5d1f7f4e09471f8d2898b5bda91c
> >>>
> >>> Also check out our FAQ.
> >>>
> >>> Best regards,
> >>> Timo
> >>> > Hi,
> >>> >
> >>> > I'm implementing a variant of strong branching within SCIP. I was
> >>> > wondering
> >>> > - what do the lpcands obtained via the function SCIPgetLPBranchCands
> >>> > correspond to?
> >>> >
> >>> > Do they correspond to the original problem variables or the
> >>> constraint
> >>> > matrix variables after presolving, etc.
> >>> >
> >>> > How can I obtain the problem variable index/column index resp. the
> >>> > variable
> >>> > is referring too?
> >>> >
> >>> > Thanks
> >>> > --Sid
> >>> > _______________________________________________
> >>> > Scip mailing list
> >>> > Scip at zib.de
> >>> > http://listserv.zib.de/mailman/listinfo/scip
> >>> >
> >>>
> >>>
> >>
> >
>
>
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