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

Jed Brown jedbrown at mcs.anl.gov
Wed Jul 11 09:19:51 CDT 2012

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.

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