[petsc-users] MatGetSubMatrix and memory usage

[Jed Brown]

On Wed, 23 Jun 2010 17:17:41 +0200, francois pacull <fpacull at fluorem.com> wrote:
> I used only 2 processes in that test.

I would have predicted lower, but there is also a matrix (used to
collect local parts) composed under "SubMatrix".  See
MatGetSubMatrix_MPIAIJ and MatGetSubMatrix_MPIAIJ_Private for details.
You can destroy them if you want, but it won't change peak usage,
unfortunately.

Jed