On Thu, Dec 15, 2011 at 1:51 PM, Ravi Kannan <rxk at cfdrc.com> wrote:
> HI Mark,**** > > ** ** > > Is this pc_type gamg and/or '-pc_gamg_type pa' or '-pc_gamg_type sa' > available for the release (3.2) version. Can it be downloaded from the > PETSc webpage? > Its there, but there are several bug fixes in dev. > Also, do you know if this will scale better than the HYPRE?s BoomerAMG? > Yes, it should. Matt > Thanks,**** > > Ravi. **** > > ** ** > > *From:* petsc-dev-bounces at mcs.anl.gov [mailto: > petsc-dev-bounces at mcs.anl.gov] *On Behalf Of *Mark F. Adams > *Sent:* Thursday, December 15, 2011 1:18 PM > *To:* For users of the development version of PETSc > *Subject:* Re: [petsc-dev] boomerAmg scalability**** > > ** ** > > ** ** > > On Dec 15, 2011, at 1:56 PM, Matthew Knepley wrote:**** > > > > **** > > On Thu, Dec 15, 2011 at 10:23 AM, Ravi Kannan <rxk at cfdrc.com> wrote:**** > > Dear All,**** > > **** > > This is Ravi Kannan from CFD Research Corporation. Recently, we are > experimenting with the BoomerAMG preconditioner for some ?stiff? CFD > problems. In that regard, all the other standard solver-preconditioner > combinations failed for the current CFD problem. The boomer is the only one > which is able to provide with ?converged? solutions.**** > > **** > > We noticed that the scalability of this boomer preconditioner is really > poor. For instance, even with a cell size of 2 million, we cannot scale to > even 16 partitions (in contrast, the other solver-preconditioner > combinations like the BI-CGS/BJacobi gave good enough scalability).**** > > **** > > Are we missing something? Do we need to use a more latest version of > boomer?**** > > ** ** > > Have you tried -pc_type gamg in petsc-dev?**** > > ** ** > > For gamg you also want to use MPIAIJ matrices and set the block size > MatSetBlockSize(mat,3), for a 3D velocity field, for instance. You can > also try '-pc_gamg_type pa' or '-pc_gamg_type sa'. "pa", for plain > aggregation might be better for CFD problems.**** > > ** ** > > Mark**** > > > > **** > > ** ** > > Matt**** > > **** > > Thanks,**** > > Ravi. **** > > ** ** > > > **** > > ** ** > > -- > 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20111215/a30d7536/attachment.html>
