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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120711/2731f34e/attachment.html>
