[petsc-users] Creating dmplex in every rank and redistributing

[Matthew Knepley]

On Mon, Jul 11, 2022 at 5:54 AM Prateek Gupta <prateekgupta1709 at gmail.com>
wrote:

> Thanks Matt.
> While looking into the function, I noted PetscHSetI and related functions
> but couldn't find their docs (404 error). Have these functions and data
> types deprecated?
>

No. These are a bit complicated because they are made by the preprocessor
from a 3rd party package.

We broke the links when we moved all the documentation to Sphinx. I will
see if I can fix them.

  Thanks,

      Matt


> Thank you.
> Sincerely,
> Prateek Gupta
>
>
> On Mon, Jul 4, 2022 at 6:09 PM Matthew Knepley <knepley at gmail.com> wrote:
>
>> On Mon, Jul 4, 2022 at 2:29 AM Prateek Gupta <prateekgupta1709 at gmail.com>
>> wrote:
>>
>>> Hi,
>>>
>>> Using dmplex, I am trying to create an example where I can start with a
>>> poor distribution of an unstructured mesh (reading from a file in parallel)
>>> and then use redistribution to optimize it.
>>>
>>
>> You can call DMPlexDistribute() on any mesh, including a parallel one.
>>
>>
>>> I know that I can call ReBalanceSharedPoints on an already created
>>> distribution from dmplexDistribute. But is it possible to initialize a
>>> dmplex from each rank (each rank initializes its own chunk of the mesh) and
>>> then call this function?
>>>
>>
>> Yes, this is done in
>>
>>
>> https://petsc.org/main/docs/manualpages/DMPLEX/DMPlexCreateFromCellListParallelPetsc/
>>
>> It is not trivial to do by hand, so I would look at that code first if
>> you want to do that.
>>
>>
>>> Most of the numbering in dmplex DAG representation is local, but while
>>> reading from a file in parallel, I only have access to global numbering of
>>> nodes. Do I need to reassign this to a local numbering? Is there a
>>> datastructure within petsc that can help with this?
>>>
>>>
>>> Thank you.
>>> Sincerely,
>>> Prateek Gupta, PhD
>>>
>> --
>> 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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