[petsc-users] Block ILU with AIJ matrix?

[Matthew Knepley]

On Mon, Oct 31, 2011 at 8:15 AM, Gong Ding <gdiso at ustc.edu> wrote:

> Yes, modern direct solver do block factorization as super node method.
> Can ASM type preconditioner use superlu ILUT on each subdomain?
>

Yes.

   Matt


> At preset, my solver (BCGS) only works with ASM+ILU(1) on a "smart
> partitioned" mesh.
>
>
> > The ILUTP in SuperLU (4.2 and up) exploits blocking (supernodes) in
> >
> > the (approximate) L & U factors.  Note the block boundary is
> >
> > discovered on the fly, which is usually larger than the block size
> >
> > from the input matrix A.  So the efficiency is pretty good.  It uses
> >
> > threshold dropping with partial pivoting, numerically is quite good
> >
> > too.    It's available only in the serial version.
> >
> >
> >
> > Sherry Li
> >
> >
> >
> >
> >
> > On Sun, Oct 30, 2011 at 11:18 PM, Jed Brown <jedbrown at mcs.anl.gov>
> wrote:
> >
> > > On Sun, Oct 30, 2011 at 23:50, Gong Ding <gdiso at ustc.edu> wrote:
> >
> > >>
> >
> > >> I had also considered use max block size. But it is not efficient
> here.
> >
> > >> Hope petsc support nonuniform block size one day.
> >
> > >
> >
> > > Inodes do a sort of partial blocking. There has to a clear performance
> >
> > > benefit to explicit variable blocking in order to justify the
> implementation
> >
> > > and interface complexity. I have not yet seen a demonstration of this.
> >
> >
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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