[petsc-users] Laplace Equation preconditioner

[Matthew Knepley]

On Wed, Oct 12, 2022 at 1:38 PM Alfredo J Duarte Gomez <aduarteg at utexas.edu>
wrote:

> Good morning PETSC users,
>
> I have a current solver that requires the solution of a Laplace equation
> to be reused for all future time steps.
>
> The configuration is axisymmetric with Dirichlet BCs at the top and bottom
> boundaries, and Zero Neumman conditions at the axis and far field. The grid
> is curvilinear and structured.
>
> So far I have been using PCHYPRE boomeramg as the preconditioner, which
> often works well, but I have also experienced DIVERGED_BREAKDOWN on many
> occasions. When I use direct solver PCMUMPS it always produces a
> satisfactory answer, which gives me confidence that the solution exists for
> the given grid in all these configurations where boomeramg fails.
>

I do not know why Hypre is breaking down. Did you try ML or GAMG? They are
easier to diagnose I think.

  Thanks,

     Matt


> I am looking for recommendations on other preconditioners to try in this
> problem that can produce a solution faster than PCMUMPS, or recommendations
> on which parameters to adjust on boomeramg.
>
> Thank you,
>
>
> --
> Alfredo Duarte
> Graduate Research Assistant
> The University of Texas at Austin
>


-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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