Independently configuring down & up smoothers in PCMG

Barry Smith bsmith at
Thu Oct 9 09:24:41 CDT 2008


     This is a good point; I'm trying to come up with a clean simple  
way to do this.


On Oct 8, 2008, at 10:14 PM, Dave May wrote:

> Howdy,
>      Should there be a mechanism to independently configure the down
> and up smoothers
> for PCMG from the command line?
> From the looks of things, it seems that on a  given level, one is only
> able to set the smoothing
> sweeps to be different via
>    -pc_mg_smoothup 3 -pc_mg_smoothdown 2
> Since both the down and up smoothers (KSP's) have the prefix set to be
> "mg_levels_X",
> it would seem that I cannot differentiate between the up ksp at level
> X from the down ksp
> at level X via any command line arguments.
> It would be pain to ALWAYS have to configure both the up and down
> smoothers independently.
> But to enable the down and up smoothers to be configured independently
> (on those odd occasions
> you want to do it) , could we do something like; set a flag via
>    -pc_mg_smoothers_different
> which would include in the smoothers prefix, the words "up" or "down"?
> Then on the command line we could do something like
>    -mg_levels_1_up_ksp_type XXX
>    -mg_levels_1_down_ksp_type YYY
> Cheers,
>    Dave

More information about the petsc-dev mailing list