[petsc-users] Does petsc4py support matrix-free iterative solvers?

[Stefano Zampini]

You can find other  examples at
https://gitlab.com/stefanozampini/petscexamples

On Tue, Mar 14, 2023, 19:50 Jose E. Roman <jroman at dsic.upv.es> wrote:

> Have a look at ex100.c ex100.py:
>
> https://gitlab.com/petsc/petsc/-/blob/c28a890633c5a91613f1645670105409b4ba3c14/src/ksp/ksp/tutorials/ex100.c
>
> https://gitlab.com/petsc/petsc/-/blob/c28a890633c5a91613f1645670105409b4ba3c14/src/ksp/ksp/tutorials/ex100.py
>
> Jose
>
>
> > El 14 mar 2023, a las 17:45, Eric Hester <eric.w.hester at icloud.com>
> escribió:
> >
> > Is there a similar example of how to create shell preconditioners using
> petsc4py?
> >
> > Thanks,
> > Eric
> >
> >> On Mar 13, 2023, at 09:37, Eric Hester <eric.w.hester at icloud.com>
> wrote:
> >>
> >> Ah ok. I see how the poisson2d example works. Thanks for the quick
> reply.
> >>
> >> Eric
> >>
> >>> On Mar 13, 2023, at 08:10, Jose E. Roman <jroman at dsic.upv.es> wrote:
> >>>
> >>> Both ode/vanderpol.py and poisson2d/poisson2d.py use shell matrices
> via a mult(self,mat,X,Y) function defined in the python side. Another
> example is ex3.py in slepc4py.
> >>>
> >>> Jose
> >>>
> >>>
> >>>
> >>>> El 13 mar 2023, a las 15:58, Eric Hester via petsc-users <
> petsc-users at mcs.anl.gov> escribió:
> >>>>
> >>>> Hello everyone,
> >>>>
> >>>> Does petsc4py support matrix-free iterative solvers (as for
> Matrix-Free matrices in petsc)?
> >>>>
> >>>> For context, I have a distributed matrix problem to solve. It comes
> from a Fourier-Chebyshev Galerkin discretisation. The corresponding matrix
> is dense, but it is fast to evaluate using fftw. It is also distributed in
> memory.
> >>>>
> >>>> While I’ve found some petsc4py tutorial examples in
> "/petsc/src/binding/petsc4py/demo/“, they don’t seem to show a matrix free
> example. And I don’t see a reference to a matrix shell create method in the
> petsc4py api.
> >>>>
> >>>> If petsc4py does support matrix free iterative solvers, it would be
> really helpful if someone could provide even a toy example of that. Serial
> would work, though a parallelised one would be better.
> >>>>
> >>>> Thanks,
> >>>> Eric
> >>>>
> >>>>
> >>>
> >>
> >
>
>
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