[petsc-dev] any way to detect if a matrix is singular?

[Matthew Knepley]

On Tue, Oct 10, 2017 at 10:36 AM, Kong, Fande <fande.kong at inl.gov> wrote:

> Hi Developers,
>
> I am trying to use the native LU in PETSc to compute a matrix (arising
> from a fluid-structure interaction problem). I encounter a zero pivot. The
> matrix gives the wrong Newton direction when using "-pc_factor_shift_type
>  nonzero -pc_factor_shift_amount 1".  I hence guess the matrix is
> singular.
>
> Any easy way to detect if or not the matrix is singular??
>

That is the easiest way, namely having LU fail. You can catch the failure
and do something useful.

  Matt


> Fande,
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20171010/28ad657d/attachment.html>