[petsc-users] snes + matrix free + coloring

[Jed Brown]

Then you aren't using a matrix-free method at all. Just don't call
SNESSetJacobian and it will be done for you. Are you using a DM? If not,
you will also need to create a MatFDColoring. The easiest way to do that,
if you don't have a structured mesh, is to assemble the nonzero pattern of
your operator.

On Wed, Oct 10, 2012 at 3:44 PM, <panourg at mech.upatras.gr> wrote:

> Is exactly the same.
>
> Kostas
>
>
>
>
>
>
> > On Wed, Oct 10, 2012 at 3:32 PM, <panourg at mech.upatras.gr> wrote:
> >
> >> Dear all
> >>
> >> I have a non-linear system which i want to solve it with matrix free
> >> method. However i must form the whole proconditioning matrix using
> >> finite
> >> differences and coloring method.
> >>
> >
> > How is the preconditioning matrix different from the actual operator?
> >
> >
> >>
> >> I can set the function F() of non-linear system (i take the notation F()
> >> from documentation).
> >>
> >> Could you send me exactly the commands and the order of it which i must
> >> use or an apt example for that?
> >>
> >> I have looked for that in internet but i could not find any suitable
> >> example.
> >>
> >> Kostas
> >>
> >> Thanks
> >>
> >>
> >
>
>
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