Why not just stop it once it is equal to or less than the minimum values set
by the person. Thus you need not "backtrack" by removing levels but the user
still has some control over preventing a "tiny" coarse problem. For example in
this case if the user set a minimum of 1000 it would end up with 642 unknowns
on the coarse level which is likely better than 6 or 54.
Barry
> On Oct 29, 2018, at 8:27 AM, Mark Adams <[email protected]> wrote:
>
>
>
> On Sun, Oct 28, 2018 at 4:54 PM Smith, Barry F. <[email protected]> wrote:
>
> Moved a question not needed in the public discussions to petsc-dev to ask
> Mark.
>
>
> Mark,
>
> PCGAMGSetCoarseEqLim - Set maximum number of equations on coarsest grid
>
> Is there a way to set the minimum number of equations on the coarse grid
> also? This particular case goes down to 6, 54 and 642 unknowns on the
> coarsest grids when I'm guessing it would be better to stop at 642 unknowns
> for the coarsest level.
>
> No, because I don't know how it is going to coarsen I did not want to bother
> with backtracking (I do when there is an error on the coarse grid so it would
> be easy to add this but I don't think it is worth the clutter).
>
