[petsc-users] MatShell & PCShell

[Jed Brown]

On Wed, 23 Jun 2010 14:32:53 +0000, "Klaij, Christiaan" <C.Klaij at marin.nl> wrote:
> Hi,
> 
> For my linear problem Ax=b I have available the vector b, the action
> Ax of the matrix and the action Px of a given preconditioner. Is this
> enough to use the Krylov solvers in PETSc? So far I've looked at ex14f
> and ex15f which use either MatShell or PCShell but not both. I'm not
> sure whether it's at all possible, so I would greatly appreciate your
> advice before starting some trial and error.

You can certainly use both, and you pretty much have to unless you have
an assembled matrix that is "similar" to your MatShell because, for
obvious reasons, PETSc's preconditioners can't do much with your
MatShell.

Jed