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

[w_ang_temp]

Thanks!




在 2012-07-11 22:19:51，"Jed Brown" <jedbrown at mcs.anl.gov> 写道：

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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