GAMG is almost algorithmically invariant but the graph coarsening is not
invariant not deterministic. You should not see much difference in teration
could but a little decay is expected.
On Wed, Apr 17, 2019 at 12:36 PM Matthew Knepley via petsc-users <
petsc-users@mcs.anl.gov> wrote:
> On Wed,
Yes - the default preconditioner is block-jacobi - with one block on
each processor.
So when run on 1 proc vs 8 proc - the preconditioner is different
(with 1block for bjacobi vs 8blocks for bjacobi)- hence difference in
convergence.
Satish
On Wed, 17 Apr 2019, Marian Greg via petsc-users
