[petsc-users] Solving NON-Diagonally dominant sparse system

[Xiaoye S. Li]

If you need to use SuperLU_DIST, the pivoting is done statically, using
maximum weighted matching, so the small diagonals are usually taken care as
well. It is not as good as partial pivoting, but works most of the time.

Sherry

On Mon, Apr 10, 2017 at 12:07 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
>    I would suggest using ./configure --download-superlu and then when
> running the program -pc_type lu -pc_factor_mat_solver_package superlu
>
>    Note that this is SuperLU, it is not SuperLU_DIST.  Superlu uses
> partial pivoting for numerical stability so should be able to handle the
> small or zero diagonal entries.
>
>     Barry
>
> > On Apr 10, 2017, at 1:17 PM, Kaushik Kulkarni <kaushikggg at gmail.com>
> wrote:
> >
> > Hello,
> > I am trying to solve a 2500x2500 sparse matrix. To get an idea about the
> matrix structure I have added a file matrix.log which contains the output
> of MatView() and also the output of Matview_draw in the image file.
> >
> > From the matrix structure it can be seen that Jacobi iteration won't
> work and some of the diagonal entries being very low(of the order of 1E-16)
> LU factorization would also fail.
> >
> > C​an someone please suggest what all could I try next, in order to make
> the solution converge?
> >
> > Thanks,
> > Kaushik
> > ​
> > --
> > Kaushik Kulkarni
> > Fourth Year Undergraduate
> > Department of Mechanical Engineering
> > Indian Institute of Technology Bombay
> > Mumbai, India
> > https://kaushikcfd.github.io/About/
> > +91-9967687150
> > <matrix.log><matrix_pattern.png>
>
>
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