[petsc-users] Questions DMPlex

[Matthew Knepley]

On Mon, Sep 30, 2024 at 6:50 AM Karthikeyan Chockalingam - STFC UKRI via
petsc-users <petsc-users at mcs.anl.gov> wrote:

> Hi,
>
>
>
> We have been using PETSc’s block version of the AIJ matrix format to
> implement fully coupled multiphysics problems using finite elements.
>
>
>
> Are there specific advantages to moving toward DMPlex for finite
> element-based coupled multi-physics implementation?
>

DMPlex is intended to help manage unstructured grids. It can read/write
meshes and functions over them, layout data over the grid
in parallel, compute local-to-global maps, modify meshes, and also provides
some tools for assembling functions and operators.


> Can you still access Hypre?
>

Yes. Hypre interacts with the solvers. DMPlex is only there to help in
assembly.


> Does the format support running on GPUs?
>

Running the solver on GPUs is unchanged. However, for assembling on GPUs,
there are at least two options:

1) Do everything yourself using the information provided by DMPlex. This is
what Mark does in dmplexland.c for
    assembling the Landau operator. It is hard, but some people can do it.

2) Use a library. LibCEED is a library for assembling on the GPU, and
DMPlex provides support for interacting with it. There
    are DMPlex examples in the LibCEED distribution. This is what I do for
assembling on GPUs.

  Thanks,

     Matt


> Thank you.
>
>
>
> Kind regards,
>
> Karthik.
>
>
>
>
>
>
>
> --
>
> *Karthik Chockalingam, Ph.D.*
>
> Senior Research Software Engineer
>
> High Performance Systems Engineering Group
>
> Hartree Centre | Science and Technology Facilities Council
>
> karthikeyan.chockalingam at stfc.ac.uk
>
>
>
>  [image: signature_3970890138]
>
>
>


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