[petsc-users] DMPlex in Fortran

[Mike Michell]

Thank you for the quick note.
To use PetscFECreateLagrange(), it is unclear about the meaning of "Nc",
which is explained as 'number of components' on the manual page.
I looked at an example with Nc=1 in
src/dm/impls/swarm/tutorials/ex1f90.F90, but could you please detail the
meaning of Nc? If only one value (component) is defined on each of p0 and
p1 DMs, is Nc=1?
Thanks,


> On Thu, Aug 25, 2022 at 12:52 PM Mike Michell <mi.mike1021 at gmail.com>
> wrote:
>
>> Hi, I am trying to find the function you commented,
>> DMPlexCreateInterpolator(), from DMPlex manual page, but I do not think
>> this function is visible. Any comment about this?
>>
>
> Sorry, it is DMCreateInterpolation(), which in turn calls
> DMPlexComputeInterpolatorNested/General.
>
>   Thanks,
>
>       Matt
>
>
>> Thanks,
>>
>>
>>> On Fri, Jul 8, 2022 at 11:26 PM Mike Michell <mi.mike1021 at gmail.com>
>>> wrote:
>>>
>>>> I am using DMPlex for a code with written in Fortran in 2D and 3D.
>>>> There were two questions.
>>>>
>>>> - As a follow up of the previous inquiry:
>>>> https://www.mail-archive.com/petsc-users@mcs.anl.gov/msg43856.html
>>>> Is the local-to-local halo exchange available in Fortran now or still
>>>> pending? Currently local-to-global and global-to-local communication are
>>>> used since local-to-local has not been allowed for Fortran.
>>>>
>>>
>>> Sorry, it is still on my TODO list. I am trying to get stuff cleared out.
>>>
>>>
>>>> - One code solves discretized equations at each vertex, and another
>>>> code I want to couple physics is solving equations at each cell centroid.
>>>> Basically, the value at cell centroid needs to be mapped to vertex (or vice
>>>> versa) through interpolation/extrapolation for coupling of two codes. Does
>>>> petsc function provide this kind of mapping between cell centroid and
>>>> vertex? The grids for the two codes can be overlapped. I was trying to find
>>>> some FEM infrastructures in petsc, but so far havent found that kind of
>>>> functionality. Can I get any comments on that?
>>>>
>>>
>>> Yes, you can create both P0 and P1 discretizations
>>> (PetscFECreateLagrange) in two different DMs using DMClone(), and then
>>> create an interpolation operator (DMPlexCreateInterpolator) which maps
>>> between them. Let me know if something is not clear there.
>>>
>>>   Thanks,
>>>
>>>     Matt
>>>
>>>
>>>> Thanks,
>>>> Mike
>>>>
>>>>
>>>
>>> --
>>> 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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