analyze preconditioned operator?

Lisandro Dalcin dalcinl at
Thu Oct 9 13:37:54 CDT 2008

Take a look at KSPComputeExplicitOperator() routine. Note that it
could be rather slow if your large matrices. Additionally, it returns
a dense matrix in the uniprocessor case.

It this trick does not fit your need, then perhaps you could use a
shell matrix having the actual Mat and a PC, but that approach is a
bit harder to setup.

On Thu, Oct 9, 2008 at 3:22 PM, Matt Funk <mafunk at> wrote:
> Hi,
> i am using PETSC and on top of it also SLEPC to do some matrix analysis.
> In Slepc i simply pass it the Petsc matrix to analyze it.
> However, is there anyway to analyze the preconditioned matrix at all?
> The only ways i can think of are either by getting the preconditioned matrix
> back out of PETSC (i.e. some sort of pointer to it if it is stored at all),
> or by Slepc applying the preconditioner (i tried to contact the developers
> but no one has responded to that question so far)?
> I looked around a little bit but i could not find anything on this.
> Does anyone have experience with this?
> thanks
> matt

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

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