[petsc-users] Solution Diverging

[Mark Adams]

So you have a 2D Poisson solver and it is working on large problems but the
linear solver is diverging on small problems.

I would verify the the solution is good on the large problem.

You might have a problem with boundary conditions. What BCs do you think
you are using?

On Fri, Apr 5, 2019 at 4:33 PM Maahi Talukder via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Dear All,
>
> I am solving a linear system arising from 9-point discretization of
> Poisson equation to generate grid. KSP solvers are giving nice converged
> result when I am dealing with a large matrix. But when I am trying to
> implement KSP solvers when the matrix is smaller and the values are smaller
> too, the solution is diverging.
> Any suggestions how to get around this problem?
>
>
> Regards,
> Maahi Talukder
>
>
>
>
>
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