[petsc-dev] WTF

Mark Adams mfadams at lbl.gov
Sat Jul 2 07:17:00 CDT 2016

On Thu, Jun 30, 2016 at 8:48 PM, Jeff Hammond <jeff.science at gmail.com>

> > The default settings often don’t work well for 3D problems.
> Are 2D (1D?) problems really the common case for PDE solvers?  Aren't
> interesting problems 3D?  Shouldn't the defaults be set to optimize for 3D?

Lots of people do 2D in production (it might just be part of a larger 3D
algorithm like the XGC code).

Also 2D is useful for debugging, regression, incremental development.

I would prefer that hypre's defaults be for 3D and I like Barry's
suggestion of changing the default with the dimension. We can get a shot at
the dimension, without any API changes, by just inferring from the block
size. Better than nothing.  But I do find it annoying to search around for
my 3D hypre parameters when I'm (customers) doing a 3D problems. I am sure
lots of cycles are wasted by PETSc users using hypre in 3D with the

> Jeff
> --
> Jeff Hammond
> jeff.science at gmail.com
> http://jeffhammond.github.io/
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