[petsc-users] local to global mapping for DMPlex

[Matthew Knepley]

On Tue, Dec 19, 2017 at 11:40 AM, Yann JOBIC <yann.jobic at univ-amu.fr> wrote:

> Hello,
>
> We want to extract the cell connectivity from a DMPlex. We have no problem
> for a sequential run.
>

Do you want it on disk? If so, you can just DMView() for HDF5. That outputs
the connectivity in a global numbering.
I can show you the calls I use inside if you want. I usually put

  DMViewFromOptions(dm, NULL, "-dm_view")

Then

  -dm_view hdf5:mesh.h5

  Thanks,

    Matt


> However for parallel ones, we need to get the node numbering in the global
> ordering, as when we distribute the mesh, we only have local nodes, and
> thus local numbering.
>
> It seems that we should use DMGetLocalToGlobalMapping (we are using
> Fortran with Petsc 3.8p3). However, we get the running error :
>
> [0]PETSC ERROR: No support for this operation for this object type
> [0]PETSC ERROR: DM can not create LocalToGlobalMapping
>
> Is it the right way to do it ?
>
> Many thanks,
>
> Regards,
>
> Yann
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
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