[petsc-users] options for gmres w/ ilu precondioner for sparse

[Matthew Knepley]

On Tue, Feb 1, 2011 at 9:03 AM, Michael E Henderson <mhender at us.ibm.com>wrote:

> Good morning,
>
> I'm trying to use gmres with an ilu preconditioner and having trouble
> getting the options right. I figure it's got to be something simple, so hope
> it's an easy question.
>

This is the joy of using other packages. Looking at the source, I see 4
packages which can factor a parallel (MPIAIJ) matrix:

  MUMPS, SuperLU_dist, Spooles (now unsupported), Pastix

These are all usable from -pc_factor_mat_solver_package when using MPIAIJ.

1) We do not consider SPAI a matrix factorization package. You just use it
with --pc_type spai

2) We cannot see inside Hypre, and thus it is hard to get into this
framework. You use Euclid with

  -pc_type hypre -pc_hypre_type euclid

    Matt


> With options:
>
> -ksp_type gmres
> -pc_type ilu
> -pc_factor_levels 10
> -pc_factor_fill 10
> -pc_factor_mat_solver_package spai
>
> I get the message:
>
>  unknown: [1|MatGetFactor() line 3646 in src/mat/interface/matrix.c: Matrix
> format mpiaij does not have a solver spai. Perhaps you must
> config/configure.py with --download-spai
>
> I checked the configuration output and spai was indeed configured and
> built. I also tried spooles with a similar result.
>
> The table
> http://www.mcs.anl.gov/petsc/petsc-as/documentation/linearsolvertable.htmlseems to be saying that only hypre/euclid can be used for ilu(k) w/ aij. Is
> that true?
>
> -pc_factor_mat_solver_package hypre
> -pc_hypre_type euclid
>
> also gives
>
> unknown: [1MatGetFactor() line 3646 in src/mat/interface/matrix.c: Matrix
> format mpiaij does not have a solver hypre. Perhaps you must
> config/configure.py with --download-hypre
>
> I'm using hypre as a preconditioer elsewhere, so I'm sure it's installed.
> Am I doing something obviously wrong?
>
> Thanks,
>
> Mike Henderson
>
> ------------------------------------------------------------------------------------------------------------------------------------
> Mathematical Sciences, TJ Watson Research Center
> mhender at watson.ibm.com
> http://www.research.ibm.com/people/h/henderson/
> http://multifario.sourceforge.net/
>



-- 
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
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