[petsc-dev] ASM request

Matthew Knepley knepley at gmail.com
Tue Mar 16 13:36:27 CDT 2010

On Tue, Mar 16, 2010 at 2:35 PM, Jed Brown <jed at 59a2.org> wrote:

> On Tue, 16 Mar 2010 14:12:03 -0400, Matthew Knepley <knepley at gmail.com>
> wrote:
> >    You have a preconditioner which is ASM, but with a LOT of small
> > blocks.  You do not save very much by discarding one big block, but if
> > you only ever form each small block, you get a lot of savings.
> Unless I misunderstand you, this means that you'll be refactoring each
> block on every Krylov iteration.  I realize it's a bit less memory, but
> that's going to be pretty painful.

If the number one thing is how big a problem can be run, they will tolerate


> Jed

What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
-- Norbert Wiener
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