[petsc-users] Questions about PCEXOTIC
Edoardo Centofanti
edoardo.centofanti01 at universitadipavia.it
Thu May 22 02:58:32 CDT 2025
Dear all,
Thank you for your answers.
Do you know which options are required for a typical use case of GDSW in
PCMG? However, I imagine that only structured DMDA meshes can be employed
with it.
Best,
Edoardo
Il giorno mer 21 mag 2025 alle ore 16:52 Barry Smith <bsmith at petsc.dev> ha
scritto:
>
> Thanks for your interest in this type of algorithm.
>
> As Pierre notes, the code is implemented only as a simple tutorial on
> one particular "exotic" wire basket-type algorithm. We don't recommend this
> implementation for more general algorithms or geometries.
>
> The face dof represents some sort of "average" of the face solution, it
> is not a point value.
>
> Barry
>
>
> On May 21, 2025, at 4:51 AM, Pierre Jolivet <pierre at joliv.et> wrote:
>
>
>
> On 21 May 2025, at 10:41 AM, Edoardo Centofanti <
> edoardo.centofanti01 at universitadipavia.it> wrote:
>
>
> Dear all,
>
> I have some questions about the PCEXOTIC preconditioner:
>
> 1- While the type "wirebasket" seems clear to me, I do not understand what
> is meant as "one dof per face" in the documentation referring to "face"
> type. Is it intended as the interpolation on the centre of the face or some
> mean value?
>
> 2- Is it possible to change the overlap between the subdomains?
>
> 3- Are there any plans of extending the implementation to unstructured
> grids (DMPlex-like)? The current one seems to rely heavily on DMDA
>
> 4- Running some preliminary tests on GPU with a code of mine that works on
> CPU, I got the following error:
>
> ** On entry to cusparseSpMM_bufferSize(): dimension mismatch,
> matA.num_rows (15405) != matC.num_rows (44955) with opA =
> CUSPARSE_OPERATION_NON_TRANSPOSE
>
> Is the preconditioner intended to run also on GPU or the error above comes
> from the fact that this feature has yet to be tested/fully implemented?
>
>
> This preconditioner is very old and the code is barely maintained.
> There is a newer implementation of the GDSW preconditioner in PCMG, see
> https://urldefense.us/v3/__https://petsc.org/release/manualpages/PC/PCMGSetAdaptCoarseSpaceType/__;!!G_uCfscf7eWS!Zmi6sdgeoCOMy1lkVGYn-ac5wvH3QEcOkYQ2VzdQgCqLY8nIVkX1oi_yt5S2vJDcF5BT8mmzOLmOUEK483D0v9_aZe01iy1b20hMB1HPuOE$
> <https://urldefense.us/v3/__https://petsc.org/release/manualpages/PC/PCMGSetAdaptCoarseSpaceType/__;!!G_uCfscf7eWS!ZDnv3udGFNlZEC_MRfLAqwvcvCObnaAjMCeyaW__UaecBvN3MkXrzOPwJJUSHXo80-xOQdLNnSf_nLmUd7bZxg$>
>
> Thanks,
> Pierre
>
> Thank you in advance,
> Best,
> Edoardo
>
>
>
--
Edoardo Centofanti
Dipartimento di Matematica 'Felice Casorati'
Università degli Studi di Pavia
Tel. 0382985608 | Ufficio A14 | Via Ferrata 5, 27100 Pavia, Italy
<https://urldefense.us/v3/__https://maps.google.com/?q=Via*20Ferrata*205,*2027100*20Pavia,*20Italy__;JSUlJSU!!G_uCfscf7eWS!Zmi6sdgeoCOMy1lkVGYn-ac5wvH3QEcOkYQ2VzdQgCqLY8nIVkX1oi_yt5S2vJDcF5BT8mmzOLmOUEK483D0v9_aZe01iy1b20hMoN_kNHg$ >
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20250522/61a83e73/attachment.html>
More information about the petsc-users
mailing list