Re: [Libmesh-users] SparseMatrix Determinant

[John P. <jwp...@gm...>]

On Wed, Aug 8, 2018 at 3:51 AM, Barna Becsek <bar...@gm...> wrote:

> Hello,
>
> is there a way to compute a SparseMatrix’s determinant? I would like to
> solve a linear system but my final residual always equals exactly 0 after
> just one iteration (where the solve terminates). Hence, I would like to
> check the matrix for singularity.
>

If you are using PETSc, for a small enough problem you could run with the
"-pc_type svd -pc_svd_monitor" command line options and look at the
singular values. If any of them are zero or nearly zero, the system is
singular.

-- 
John