[petsc-users] Functions for judging the properties of the matrix

[Jed Brown]

On Wed, Jul 11, 2012 at 8:51 AM, w_ang_temp <w_ang_temp at 163.com> wrote:

>
> Hello,
>
>     Is there function in PETSc for judging the properties of the matrix A
> ? Such as positive definitiveness and
>
> conditional number. I know that there are several functions begin with
> MatIs+, but it has limited amounts.
>

The Ritz values are estimates of the eigenvalues that you can obtain using
KSPSolve() with -ksp_compute_eigenvalues or -ksp_plot_eigenvalues. Note
that these are estimates for the _preconditioned_ operator, so you should
use -pc_type none if you want estimates for the original operator.

http://www.mcs.anl.gov/petsc/documentation/faq.html#conditionnumber
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