[petsc-users] DMPlex Distribution

[Matthew Knepley]

On Wed, Sep 18, 2019 at 10:27 AM Mohammad Hassan <mhbaghaei at mail.sjtu.edu.cn>
wrote:

> I want to implement block-based AMR, which turns my base conformal mesh to
> non-conformal.  My question is how DMPlex renders a mesh that it cannot
> support non-conformal meshes.
>

Mark misspoke. Plex _does_ support geometrically non-conforming meshing,
e.g. "hanging nodes". The easiest way to
use Plex this way is to use DMForest, which uses Plex underneath.

There are excellent p4est tutorials. What you would do is create your
conformal mesh, using Plex if you want, and
use that for the p4est base mesh (you would have the base mesh be the
forest roots).

  Thanks,

     Matt


> If DMPlex does not work, I will try to use DMForest.
>
>
>
> *From:* Matthew Knepley [mailto:knepley at gmail.com]
> *Sent:* Wednesday, September 18, 2019 9:50 PM
> *To:* Mohammad Hassan <mhbaghaei at mail.sjtu.edu.cn>
> *Cc:* Mark Adams <mfadams at lbl.gov>; PETSc <petsc-users at mcs.anl.gov>
> *Subject:* Re: [petsc-users] DMPlex Distribution
>
>
>
> On Wed, Sep 18, 2019 at 9:35 AM Mohammad Hassan via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
> If DMPlex does not support, I may need to use PARAMESH or CHOMBO. Is there
> any way that we can construct non-conformal layout for DM in petsc?
>
>
>
> Lets see. Plex does support geometrically non-conforming meshes. This is
> how we support p4est. However, if
>
> you want that, you can just use DMForest I think. So you jsut want
> structured AMR?
>
>
>
>   Thanks,
>
>
>
>     Matt
>
>
>
>
>
> *From:* Mark Adams [mailto:mfadams at lbl.gov]
> *Sent:* Wednesday, September 18, 2019 9:23 PM
> *To:* Mohammad Hassan <mhbaghaei at mail.sjtu.edu.cn>
> *Cc:* Matthew Knepley <knepley at gmail.com>; PETSc users list <
> petsc-users at mcs.anl.gov>
> *Subject:* Re: [petsc-users] DMPlex Distribution
>
>
>
> I'm puzzled. It sounds like you are doing non-conforming AMR (structured
> block AMR), but Plex does not support that.
>
>
>
> On Tue, Sep 17, 2019 at 11:41 PM Mohammad Hassan via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
> Mark is  right. The functionality of AMR does not relate to
> parallelization of that. The vector size (global or local) does not
> conflict with AMR functions.
>
> Thanks
>
>
>
> Amir
>
>
>
> *From:* Matthew Knepley [mailto:knepley at gmail.com]
> *Sent:* Wednesday, September 18, 2019 12:59 AM
> *To:* Mohammad Hassan <mhbaghaei at mail.sjtu.edu.cn>
> *Cc:* PETSc <petsc-maint at mcs.anl.gov>
> *Subject:* Re: [petsc-users] DMPlex Distribution
>
>
>
> On Tue, Sep 17, 2019 at 12:03 PM Mohammad Hassan <
> mhbaghaei at mail.sjtu.edu.cn> wrote:
>
> Thanks for suggestion. I am going to use a block-based amr. I think I need
> to know exactly the mesh distribution of blocks across different processors
> for implementation of amr.
>
>
>
> Hi Amir,
>
>
>
> How are you using Plex if the block-AMR is coming from somewhere else?
> This will help
>
> me tell you what would be best.
>
>
>
> And as a general question, can we set block size of vector on each rank?
>
>
>
> I think as Mark says that you are using "blocksize" is a different way
> than PETSc.
>
>
>
>   Thanks,
>
>
>
>     Matt
>
>
>
> Thanks
>
> Amir
>
>
>
> *From:* Matthew Knepley [mailto:knepley at gmail.com]
> *Sent:* Tuesday, September 17, 2019 11:04 PM
> *To:* Mohammad Hassan <mhbaghaei at mail.sjtu.edu.cn>
> *Cc:* PETSc <petsc-users at mcs.anl.gov>
> *Subject:* Re: [petsc-users] DMPlex Distribution
>
>
>
> On Tue, Sep 17, 2019 at 9:27 AM Mohammad Hassan via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
> Hi
>
> I am using DMPlexCreateFromDAG() to construct my DM. Is it possible to set
> the distribution across processors manually. I mean, how can I set the
> share of dm on each rank (local)?
>
>
>
> You could make a Shell partitioner and tell it the entire partition:
>
>
>
>
> https://www.mcs.anl.gov/petsc/petsc-master/docs/manualpages/DMPLEX/PetscPartitionerShellSetPartition.html
>
>
>
> However, I would be surprised if you could do this. It is likely that you
> just want to mess with the weights in ParMetis.
>
>
>
>   Thanks,
>
>
>
>     Matt
>
>
>
> Thanks
>
> Amir
>
>
>
>
> --
>
> 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.cse.buffalo.edu/~knepley/>
>
>
>
>
> --
>
> 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.cse.buffalo.edu/~knepley/>
>
>
>
>
> --
>
> 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.cse.buffalo.edu/~knepley/>
>


-- 
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.cse.buffalo.edu/~knepley/>
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