Preconditioner for bicg

[Lisandro Dalcin]

But for cgne, looking at the code, ApplyTranspose seems to be optional...

On 10/11/07, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> [bsmith:~] bsmith% cd Src/petsc-dev/src/ksp/ksp/impls
> [bsmith:ksp/ksp/impls] bsmith% grep ApplyTranspose */*.c
> bicg/bicg.c:  ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr);
> bicg/bicg.c:       ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr);
> bicg/bicg.c:       ierr = KSP_PCApplyTranspose(ksp,Rl,Zl);CHKERRQ(ierr);
>
> [bsmith:ksp/ksp/impls] bsmith% grep ApplyTranspose */*/*.c
> cg/cgne/cgne.c:  ierr = PCApplyTransposeExists(ksp->pc,&transpose_pc);CHKERRQ(ierr);
> cg/cgne/cgne.c:    ierr = KSP_PCApplyTranspose(ksp,T,Z);CHKERRQ(ierr);
> cg/cgne/cgne.c:  ierr = KSP_PCApplyTranspose(ksp,T,Z);CHKERRQ(ierr);
>
>   These are the two methods that require the transpose operation.
>
>   I have documented both of their manual pages to indicate this.
>
>    Barry
>
>
> On Thu, 11 Oct 2007, Keita Teranishi wrote:
>
> > Hi Barry,
> >
> > Could you suggest any other KSP solvers that have the same type of problems?
> >
> > Thanks,
> > ================================
> >  Keita Teranishi
> >  Math Software Group
> >  Cray Inc.
> >  keita at cray.com
> > ================================
> >
> > -----Original Message-----
> > From: owner-petsc-users at mcs.anl.gov [mailto:owner-petsc-users at mcs.anl.gov] On Behalf Of Barry Smith
> > Sent: Thursday, October 11, 2007 4:50 PM
> > To: petsc-users at mcs.anl.gov
> > Subject: Re: Preconditioner for bicg
> >
> >
> >   For some preconditioners it is simply not easily possible to apply the
> > transpose of the preconditioner. Even multigrid requires some work to do this.
> >
> >    Barry
> >
> >
> > On Thu, 11 Oct 2007, Keita Teranishi wrote:
> >
> > > Hi,
> > >
> > >
> > >
> > > I'd like to make sure preconditioners supported for bicg. I found bicg only accepts preconditioners that is interfaced through PCApplyTranspose.
> > >
> > > For this reason, I see several preconditioners fails with bicg.
> > >
> > >
> > >
> > > Thanks,
> > >
> > > ================================
> > >  Keita Teranishi
> > >  Math Software Group
> > >  Cray Inc.
> > >  keita at cray.com
> > > ================================
> > >
> > >
> > >
> > >
> >
> >
>
>


-- 
Lisandro Dalcín
---------------
Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
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