[petsc-dev] Mark, what's the rational for keeping the Chebyshev tuning inside GAMG?

[Jed Brown]

Barry Smith <bsmith at mcs.anl.gov> writes:

>   Mark,
>
>    What's the rational for keeping the Chebyshev tuning inside GAMG
>    that duplicates that is already support by KSPChebyshev ? I'd like
>    to remove this chunk of code from GAMG since it is duplicative and
>    instead make sure that the Chebyshev tuning inside the KSPChebyshev
>    provides everything that is needed.

Note that GAMG smoothing cannot use SOR preconditioning, but you
insisted that PCMG should use Cheby/SOR instead of Cheby/Jacobi by
default.

>    Also in particular what about the /* zeroing out BC rows -- needed for crazy matrices */ should this be ported to KSPChebyshev ?
>
>     /* create cheby smoothers */
>     for (lidx = 1, level = pc_gamg->Nlevels-2; lidx <= fine_level; lidx++, level--) {
>       KSP       smoother;
>       PetscBool flag,flag2;
>       PC        subpc;
>
>       ierr = PCMGGetSmoother(pc, lidx, &smoother);CHKERRQ(ierr);
>       ierr = KSPGetPC(smoother, &subpc);CHKERRQ(ierr);
>
>       /* do my own cheby */
>
> Thanks
>
>    Barry
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