Re: Schur complement system

[Kathrin Burckhardt <tribur@xxxxxxxxxxxxxxxxx>]

Hi Matt,

1. Where do I integrate the application of the Schur system using
   MATSHELL? Can I use KSP?

2. I already have the local Schur complements computed. Is it advisable
   to once setup the global Schur matrix using MATIS and then use KSP,
   instead of the application of the Schur complement, i.e. the two
   MatMult() and the KSPSolve(), at each iteration?

Thank you,
Kathrin


> Yes, you can certainly solve this system. Normally, you would just create a
> simple MATSHELL to apply the Schur complement, which does two MatMult()s
> and one KSPSolve(). We are integrating specific support for this, but it will
> not be released until the summer I think.
>
>  Thanks,
>
>     Matt
>
> On Fri, Mar 7, 2008 at 5:50 AM, Kathrin Burckhardt
> <tribur@xxxxxxxxxxxxxxxxx> wrote:
> > Dear nice people,
> >
> >  Did you ever try to solve a Schur complement system using PETSc?