[petsc-users] two-level Schwarz: PCMG or PCComposite

[Jed Brown]

Fixed in petsc-dev, thanks.

http://petsc.cs.iit.edu/petsc/petsc-dev/rev/2abe2ed8a15d

The type was only recorded when set via -pc_composite_type.
PCCompositeSetType() was using the type, but not recording it.

On Mon, May 28, 2012 at 4:11 AM, Hui Zhang <mike.hui.zhang at hotmail.com>wrote:

> I use -ksp_view to check the PCComposite used by the ksp, but whatever
> type I set for pccomposite,
> using PCCompositeSetType, the output from -ksp_view always says it was
> ADDITIVE
>
> PC Object: 1 MPI processes
>  type: composite
>  Composite PC type - ADDITIVE
>  PCs on composite preconditioner follow
>
> On the other hand, I saw from -ksp_monitor that GMRES iterations are
> different.
>
> Thanks!
> Hui
>
>
> On May 11, 2012, at 2:55 PM, Barry Smith wrote:
>
> >
> >  If this is what you want to do then just use the PCCOMPOSITE. Use
> PC_COMPOSITE_SYMMETRIC_MULTIPLICATIVE
> >
> >   Barry
> >
> > On May 11, 2012, at 6:26 AM, Hui Zhang wrote:
> >
> >> I want to implement the two-level Schwarz method.  Let us denote P as
> the one-level
> >> Schwarz projection and P_0 as the coarse projection.  If I want the
> hybrid form of
> >> preconditioned system as follows:
> >>
> >>    (I-P_0) P (I-P_0)
> >>
> >> which is suitable:  PCMG or PCComposite?  It seems to me that
> PCComposite is good.
> >> But PCMG is not suitable because it can only implement the following
> form:
> >>
> >>    (I-P) P_0 (I-P)
> >>
> >> Any opinions?  Thanks!
> >>
> >>
> >
> >
>
>
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