How can I compute condition number

[Matthew Knepley]

On 9/24/06, Gong Ding <gdiso at ustc.edu> wrote:
>
> Hi,
>    I meet some convergince problem with my
> semiconductor simulation code. I 'd like to check
> the condition number of Jacobian matrix. How can I
> do with PETSC?


The true L_2 condition number would involve a very large
SVD calculation, and thus is rarely computed. We do have
the option:

   -ksp_compute_singularvalues

which will give you the condition number of the Krylov matrix,
a low-dimensional approximation of your matrix. A very
convenient form of this is:

   -ksp_singmonitor

which includes this information in the KSP monitor.

  Thanks,

     Matt

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