[petsc-dev] DMPlex overlap redistribution

[Matthew Knepley]

On Sun, Mar 3, 2024 at 9:48 PM Adrian Croucher <a.croucher at auckland.ac.nz>
wrote:

> hi Matt,
> On 4/03/24 3:25 pm, Matthew Knepley wrote:
>
>
> So here I am guessing that the interior cells (rock matrix) mess with the
> stratum consistency
> (ordering of dimension by stratum in the DAG). So some questions:
>
> 1) Are rock matrix cells always associated with only one regular cell?
>
> Yes. In the simplest case, each regular cell with dual porosity has one
> interior cell nested inside it. There is an interior "face" between the
> regular cell and the interior one. (I also add an interior "edge" and
> "vertex" so that the DAG has the same depth everywhere.) As well as
> computing flows between regular cells I compute flows between regular cells
> and their interior cells.
>
>
> 2) Do the rock matrix cells hold values that need to be communicated?
>
> Yes. To begin with I add interior cells on the same process as their
> parent regular cells. But if dual porosity is only in certain parts of the
> mesh, this can lead to poor load balancing. So I redistribute, but that can
> mean interior cells may no longer be on the same process as their parent
> regular cells, in which case communication is needed.
>
>
> 3) Do you use the topological operations for them, or might we reproduce
> this effect by just
>     marking the cells with rock matrix cells in them using a DMLabel?
>
> Once the dual-porosity mesh is set up, the interior cells and faces are
> treated the same as the regular ones, so I use e.g. DMPlexGetSupport() to
> get the cells on either side of an interior face when computing flow across
> it. (Not sure if that is the kind of topological operation you meant.)
>
> It has all been working fine with PETSc 3.15 since 2020! But because of
> the low-level surgery I guess it is vulnerable to changes.
>
Okay, that sounds like it should still work. I think we can just debug it.
I did not change anything that should affect this process.

Let's start with the distribution. I think the problem may be here. Even
with dual porosity cells, I don't think we should have cells in the
pointSF, just the internal face between cells. Do you agree?

  Thanks,

     Matt


> - Adrian
>
> --
> Dr Adrian Croucher
> Senior Research Fellow
> Department of Engineering Science
> Waipapa Taumata Rau / University of Auckland, New Zealand
> email: a.croucher at auckland.ac.nz
> tel: +64 (0)9 923 4611
>
>

-- 
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://urldefense.us/v3/__https://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!fRMXeHmMnS3UGrlOt-4O4SzAdAFjr8mN01vEo_NufOII-Ki1EfEE_xvPiTBYvLmY6vxUcR97u725Xg3erlnO$  <https://urldefense.us/v3/__http://www.cse.buffalo.edu/*knepley/__;fg!!G_uCfscf7eWS!fRMXeHmMnS3UGrlOt-4O4SzAdAFjr8mN01vEo_NufOII-Ki1EfEE_xvPiTBYvLmY6vxUcR97u725XoUGcVt7$ >
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20240304/0a599eb4/attachment.html>