[petsc-users] Near nullspace for preconditioners other than GAMG?

[Mark Adams]

FYI, stüben used classical AMG for elasticity but he has articulated his
code for elasticity more than Hypre as I understand it.  Hypre can work OK
for elasticity in my experience.  Its worth a try.

Mark

On Thu, Mar 5, 2015 at 5:27 PM, David Knezevic <david.knezevic at akselos.com>
wrote:

> OK, got it, thanks!
>
> David
>
>
> On Thu, Mar 5, 2015 at 5:08 PM, Jed Brown <jed at jedbrown.org> wrote:
>
>> David Knezevic <david.knezevic at akselos.com> writes:
>> > I was just wondering if its possible to achieve the same sort of thing
>> with
>> > other AMG solvers (e.g. BoomerAMG)? I assume that MatSetNearNullSpace
>> does
>> > nothing for external solvers like hypre, right?
>>
>> It is used by ML (smoothed aggregation), but not BoomerAMG (classical
>> AMG) which uses an algorithm that doesn't have a natural place for such
>> information.  To my knowledge, classical AMG is not widely used for
>> elasticity.  It is very robust for M-matrices.
>>
>
>
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