On 27/3/2014 12:14 AM, Matthew Knepley wrote:
On Wed, Mar 26, 2014 at 10:42 AM, TAY wee-beng <[email protected]
<mailto:[email protected]>> wrote:
On 26/3/2014 11:22 PM, Matthew Knepley wrote:
On Wed, Mar 26, 2014 at 9:59 AM, TAY wee-beng <[email protected]
<mailto:[email protected]>> wrote:
Hi,
I am running a CFD solver. The Poisson eqn was originally
solved using HYPRE's geometric multigrid.
Is this on a structured grid?
Yes.
Then you can replicate the Hypre structured MG with the PCMG, and it
can be lighter memory than GAMG. You
will need to code the problem in the style of SNES ex5, which is a
Poisson for which geometric MG works from
the command line.
Thanks,
Matt
Hi Matt,
First of all, is there an easier way out? Is it Boomeramg or GMRES which
has a large memory requirement? Will changing e.g. GMRES to FGMRES or
other ksp solvers solve the problem?
Also, I switched from geometric multigrid (GMG) to Boomeramg because the
latter is faster. If I use PCMG, am I going back to the GMG path, which
was slower?
Thanks!
Matt
Recently, I tested it with Boomeramg as the preconditioner
and GMRES as the ksp solver. There's a 20% increase in speed.
However, when I increased the grid resolution, I got the out
of memory error. Changing the solver back to HYPRE solved the
problem.
So does GMRES + Boomeramg used more memory than other
solvers? Are there alternatives?
Thank you.
--
Yours sincerely,
TAY wee-beng
--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to
which their experiments lead.
-- Norbert Wiener
--
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which
their experiments lead.
-- Norbert Wiener
