On Mon, Jan 9, 2012 at 13:11, TAY wee-beng <zonexo at gmail.com> wrote:
> Can you explain a bit more about how to adjust the subdomain aspect ratios > so that strongly coupled cells tend to reside on the same process? > You can set the lx,ly,lz in DMDACreate3d(). > > >> using fractional mtd which solves the momentum and Poisson eqns. I >> construct the linear eqn matrix and insert them in PETSc matrix/vectors. >> Then I solve using Bicsstab and hypre AMG respectively. Why is PCSetUp() >> and PCApply using more time? >> > > It is expensive because BoomerAMG setup and apply is expensive. > > > So this is normal? Is there any suggestion to improve performance? > This is normal for BoomerAMG. You could use PCGAMG (-pc_type gamg, better with petsc-dev) or ML (--download-ml, then -pc_type ml) which are algebraic multigrid methods that are usually less expensive to setup and per iteration (but sometimes less strong). Geometric multigrid is another possibility. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120109/b17f6be8/attachment.htm>
