[petsc-users] Hypre's BoomerAMG vs PETSc's GAMG?

[Mark Adams]

And I will just add that performance is sensitive to parameters. The
defaults try to be conservative and hypre's seem to be geared for 2D low
order discretizations.  GAMG is probably a bit more geared for 3D.  If you
are interested in looking this carefully you can run GAMG with '-info', and
grep on GAMG, and send us the results and we can verify that it running OK.
Also run with -log_summary and send that separately.  The two solvers
should be about the same speed on your problem.


On Fri, Sep 18, 2015 at 7:36 AM, Jed Brown <jed at jedbrown.org> wrote:

> Justin Chang <jychang48 at gmail.com> writes:
> > I see that there's GAMG and there's Hypre's BoomerAMG (and perhaps others
> > too?)
>
> ML
>
> > What exactly is the difference between these two? Do they have very
> > different implementations under the hood? Does one have better
> > scalability over another? Or more importantly, when would I choose one
> > over the other?
>
> BoomerAMG is classical AMG, which is a different coarsening strategy
> From GAMG and ML which use smoothed aggregation.  The math is different
> and the implementation is different.  ML and GAMG have similar math and
> there exist configurations that are equivalent.
>
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