[petsc-users] Help with ML/BoomerAMG

[Gaetan Kenway]

To Karthik

Yes, GMRES is my nominal default. For systems that are easier to solve,
TFQMR also seems to  be competitive with GMRES. It is the high mach RANS
problems with strong shocks shock induced flow separation that seem to give
me the most trouble.

Gaetan

On Mon, Apr 29, 2013 at 10:07 PM, Gaetan Kenway <gaetank at gmail.com> wrote:

> That makes sense. Is there a reasonably easy way of doing that in PETSc
> currently for reasonably large systems?
>
> Gaetan
>
>
> On Mon, Apr 29, 2013 at 4:32 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>
>> Gaetan Kenway <gaetank at gmail.com> writes:
>>
>> > I would be very interested in looking at the problematic eigenmodes as
>> > well. On my end I use Tecplot for all my visualization.  What sort of
>> > visualization technique are you thinking about? Is it the KSP subspace
>> > vectors you want to look at?
>>
>> No, it would be an eigensolve for either outliers or eigenvalues very
>> close to zero.  The cost to find the vector is like several solves, but
>> it would tell us exactly what sort of functions are poorly approximated
>> by the preconditioner.  Then we would think about how we can change
>> algorithms to make the preconditioner correct those functions better.
>>
>
>
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