[petsc-users] question about PC_BJACOBI

[Jed Brown]

On Thu, Sep 23, 2010 at 16:41, Leo van Kampenhout
<lvankampenhout at gmail.com> wrote:
>
> Thank you both. The solvers are the same, I double checked that. It could be
> the case that the type of partitioning plays a role here, since i'm indeed
> using a DA. However, why is it that for example a run on 2 processors the
> number of iterations is higher than on 8?

Does this also happen with direct subdomain solves?  -sub_pc_type lu

> Both use DA-partitioning in this
> case. To specify subdomains manually, where do i start?

PCASMSetLocalSubdomains (use ASM with overlap 0 for this: -pc_type asm
-pc_asm_overlap 0).

Jed