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

Jed Brown jed at jedbrown.org
Sun Feb 22 20:48:51 CST 2015

Barry Smith <bsmith at mcs.anl.gov> writes:
>   Jed,
>    Wrong, wrong, wrong. You are looking at the wrong place in the
>    code. (Yes, this is a problem with duplicate code in THREE!
>    places). I am referring to the code around line 795 in gamg.c /* do
>    my own cheby */ which I actually cut and pasted into my previous
>    email. You are referring to the code in agg.c around line 1209
>    which does what you said. 

Okay, yes.

>    The code I am referring to computes the estimates used by the
>    smoother on each level and thus forces a bypass of the code in
>    Chebyshev.c it seems completely unneeded to me (aside from maybe
>    the hack for crazy matrices) since Chebyshev.c will do it next
>    automatically anyways.

Yeah. It would be nice to avoid repeating the estimate when the smoother
matches the AMG smoothing.
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