[Carpet] buffer zones

[Frank Loeffler]

Hi,

Ian Hawke wrote:
> If using internal buffer zones

Yes, still. I know ...

> then you nullify the effect of the mesh
> refinement (as interpolating from the coarse grid loses you the
> additional accuracy that the fine grid should give you).

Ok, that is the loss of performance I was talking about. I am more 
concerned of lower convergence than expected.

> With _really_
> too many buffer zones you're just doing an expensive unigrid run with a
> weird dissipation algorithm!

I have 6 instead of the needed 4. I think this does not count as _really_?

Frank