[petsc-users] Copying PETSc Objects Across MPI Communicators

[Jed Brown]

You can place it in a parallel Mat (that has rows or columns on only one rank or a subset of ranks) and then MatCreateSubMatrix with all new rows/columns on a different rank or subset of ranks.

That said, you usually have a function that assembles the matrix and you can just call that on the new communicator.

Damyn Chipman <damynchipman at u.boisestate.edu> writes:

> Hi PETSc developers,
>
> In short, my question is this: Does PETSc provide a way to move or copy an object (say a Mat) from one communicator to another?
>
> The more detailed scenario is this: I’m working on a linear algebra solver on quadtree meshes (i.e., p4est). I use communicator subsets in order to facilitate communication between siblings or nearby neighbors. When performing linear algebra across siblings (a group of 4), I need to copy a node’s data (i.e., a Mat object) from a sibling’s communicator to the communicator that includes the four siblings. From what I can tell, I can only copy a PETSc object onto the same communicator.
>
> My current approach will be to copy the raw data from the Mat on one communicator to a new Mat on the new communicator, but I wanted to see if there is a more “elegant” approach within PETSc.
>
> Thanks in advance,
>
> Damyn Chipman
> Boise State University
> PhD Candidate
> Computational Sciences and Engineering
> damynchipman at u.boisestate.edu