[petsc-users] DMPlex/PetscSF How to determine if local topology is other rank's ghost?

[Ferrand, Jesus A.]

Dear PETSc team:

I am working with a non-overlapping distributed plex (i.e., when I call DMPlexDistribute(), I input overlap = 0), so only vertices and edges appear as ghosts to the local ranks.
For preallocation of a parallel global stiffness matrix for FEA, I want to determine which locally owned vertices are ghosts to another rank.

From reading the paper on PetscSF (https://ieeexplore.ieee.org/document/9442258) I think I can answer my question by inspecting the PetscSF returned by DMPlexDistribute() with PetscSFGetGraph(). I am just confused by the root/leaf and ilocal/iremote terminology.

I read the manual page on PetscSFGetGraph() (https://petsc.org/release/docs/manualpages/PetscSF/PetscSFGetGraph.html) and that gave me the impression that I need to PetscSFBcast() the point IDs from foreign ranks to the local ones.

Is this correct?


[https://ieeexplore.ieee.org/assets/img/ieee_logo_smedia_200X200.png]<https://ieeexplore.ieee.org/document/9442258>
The PetscSF Scalable Communication Layer | IEEE Journals & Magazine | IEEE Xplore<https://ieeexplore.ieee.org/document/9442258>
PetscSF, the communication component of the Portable, Extensible Toolkit for Scientific Computation (PETSc), is designed to provide PETSc's communication infrastructure suitable for exascale computers that utilize GPUs and other accelerators. PetscSF provides a simple application programming interface (API) for managing common communication patterns in scientific computations by using a star ...
ieeexplore.ieee.org





Sincerely:

J.A. Ferrand

Embry-Riddle Aeronautical University - Daytona Beach FL

M.Sc. Aerospace Engineering | May 2022

B.Sc. Aerospace Engineering

B.Sc. Computational Mathematics



Sigma Gamma Tau

Tau Beta Pi



Phone: (386)-843-1829

Email(s): ferranj2 at my.erau.edu

    jesus.ferrand at gmail.com
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