Using -pctype mg -pcmgtype PC_MG_MULTIPLICATIVE

[Hong Zhang]

On Thu, 16 Aug 2007, Ben Tay wrote:

> Btw, is the file to download
> ftp://ftp.mcs.anl.gov/pub/petsc/externalpackages/ml-5.0.tar.gz?

Yes. You can simply use '--download-ml=1' during configuration.

Run your program with '-help' to see all options for using ml.
See ~petsc/src/ksp/ksp/examples/tests/ex26.c on how to use ML.

Hong

>
> Thanks
>
> Matthew Knepley wrote:
> > The multigrid PC needs information about the grid and discretization. If you
> > cannot provide this, use AMG through Hypre or ML. Or if you have a
> > structured grid, consider using DMMG.
> >
> >   Thanks,
> >
> >     Matt
> >
> > On 8/15/07, Ben Tay <zonexo at gmail.com> wrote:
> >
> >> Hi,
> >>
> >> I found that there's a multigrid option in the manual which can be used
> >> by adding -pctype mg -pcmgtype PC_MG_MULTIPLICATIVE.
> >>
> >> However, it seems that I am actually just using LU since with or without
> >> this option, I got exactly the same answer. Am I using multigrid the
> >> wrong way?
> >>
> >> Thanks
> >>
> >>
> >>
> >
> >
> >
>
>