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Re: whether do I need to consider the symmetric preconditioner when using CG?

To: petsc-users@xxxxxxxxxxx
Subject: Re: whether do I need to consider the symmetric preconditioner when using CG?
From: Yujie <recrusader@xxxxxxxxx>
Date: Wed, 16 Jan 2008 09:15:43 -0800
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Dear Lisandro:

From PETSc manual, I know KSPCG only supports left preconditioning. However, I want to know whether does this affect the performance of preconditioned CG? The main problem is that it should be better to generate a symmetric preconditioned operator for CG method. However, Left preconditioner should have some difficulty to get such operator? Do you have any testings about it regarding left, split and right preconditinoers and CG realization in PETSc? thanks a lot.

Regards,
Yujie

On 1/16/08, Lisandro Dalcin <dalcinl@xxxxxxxxx> wrote:

KSPCG only supports left preconditioning.

On 1/16/08, Yujie <recrusader@xxxxxxxxx> wrote:
> hi, everyone
>
> I know there are three types of preconditioners, that is left, split and
> right preconditioners? When I use CG method in PETSc, whether do I need to
> consider select one type of preconditioner? Whether do different types
> affect the performance of preconditioned CG? thanks a lot.
>
> Regards,
> Yujie
>

--
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
PTLC - Güemes 3450, (3000) Santa Fe, Argentina
Tel/Fax: +54-(0)342-451.1594

Follow-Ups:
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References:
- whether do I need to consider the symmetric preconditioner when using CG?
  - From: Yujie
- Re: whether do I need to consider the symmetric preconditioner when using CG?
  - From: Lisandro Dalcin

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