[petsc-users] Linear solver diverging

[Matthew Knepley]

On Wed, Apr 1, 2015 at 10:51 AM, bichinhoverde <
bichinhoverde at spwinternet.com.br> wrote:

> I have a linear system which I can easily solve using the Pardiso library,
> which is a direct solver. But when I try Petsc, the solver does not
> converge. It reduces the norm a little but then gets stuck.
>
> I tried several combinations of pc_type and ksp_type. It seems that
> pc=jacobi is better, since my linear system does not have the diagonal
> element in some rows.
>
> Is there some advice you can give me? Some way to analyse the matrix and
> find out why it does not work?
>

Without knowing anything about the system, there is nothing you can say.

Why do you want to change from using a direct solver?

Have you looked in the literature for iterative solvers that work on this
problem?

  Thanks,

    Matt

-- 
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
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