[petsc-users] How can I get the global integer ids in a label?

[leejearl]

Hi, Matt:	Thanks for your helps. I will tell you if the code of
"SNES ex12" can solve my problem.leejearl  On Thu, 2018-12-06 at 20:26
-0500, Matthew Knepley wrote:
> On Thu, Dec 6, 2018 at 8:06 PM leejearl <leejearl at mail.nwpu.edu.cn>
> wrote:
> > Hi Matt:
> > 	Thank you for your helps. I want to implement the periodic
> > boundary in dmplex. For a cell or face, the donor cell or face
> > might be not distributed in the same local dm. Maybe I should ask
> > that how
> > can I implement the topology of the periodic boundary in demplex.
> 
> Plex directly encodes a periodic topology. For example, with a
> circle, each vertex is connectedto two neighbors. There are example
> with periodic boundary conditions like SNES ex12.
>  Thanks,
>     Matt 
> >         Thanks again for your kind reply.
> > 
> > leejearl
> > On Thu, 2018-12-06 at 12:02 -0500, Matthew Knepl
> > > On Thu, Dec 6, 2018 at 9:47 AM leejearl via petsc-users <
> > > petsc-users at mcs.anl.gov> wrote:
> > > > Hi, Petsc developer:
> > > > 
> > > >         I have a problem for helps. 
> > > > 
> > > >         There is a dmplex object, and I have distribute it use
> > > > the
> > > > 
> > > > routine DMPlexDistribute(). Then, I want to get the global
> > > > integer ids
> > > > 
> > > > in the label "Face Sets". The code is as follow,
> > > > 
> > > > 
> > > > 
> > > >      ierr = DMGetLabelIdIS(dm, "Face Sets",
> > > > &bcIdIS);CHKERRQ(ierr);
> > > > 
> > > > 
> > > > 
> > > > The values of bcIdIs are the local integer ids. How can I get
> > > > the
> > > > 
> > > > global integer ids.
> > > > 
> > > > 
> > > > 
> > > > The problem also can be described as follow. The global ids
> > > > might look
> > > > 
> > > > likes
> > > > 
> > > > 
> > > > 
> > > > IS Object: 1 MPI processes
> > > > 
> > > >   type: general
> > > > 
> > > > Number of indices in set 4
> > > > 
> > > > 0 1
> > > > 
> > > > 1 4
> > > > 
> > > > 2 3
> > > > 
> > > > 3 2
> > > > 
> > > > 
> > > > 
> > > > But after the dm is distributed, I can only get the local ids
> > > > as follow
> > > > 
> > > > using the routine "DMGetLabelIdIS" 
> > > > 
> > > > 
> > > > 
> > > > IS Object: 1 MPI processes
> > > > 
> > > >   type: general
> > > > 
> > > > [0] Number of indices in set 3
> > > > 
> > > > [0] 0 1
> > > > 
> > > > [0] 1 2
> > > > 
> > > > [0] 2 4
> > > > 
> > > > 
> > > > 
> > > > How can I get the global integer ids in a label after the dm is
> > > > 
> > > > distributed?
> > > > 
> > > > 
> > > > 
> > > > Any helps are appreciate! 
> > > 
> > > You can make a conversion from local point numbers to global
> > > point numbers using
> > >   
> > > https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexCreatePointNumbering.html
> > > You could even make a replacement DMLabel with the global point
> > > numbers, but I think the win would be smallor nonexistent for
> > > most cases.
> > >   Thanks,
> > >     Matt 
> > > > Thanks
> > > > 
> > > > 
> > > > 
> > > > leejearl
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > 
> > > 
> 
> 
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