none: Do nothing during synchronization, prolongation, or restriction; the respective grid points remain untouched, and if not otherwise defined, remain undefined. This is commonly used e.g. for integer values that are calculated or determined pointwise.
sync: Synchronize only, do nothing for prolongation or restriction. This is similarly useful e.g. for integer data.
restrict: Only synchronize and restrict from coarser to finer grids, do nothing during prolongation. For vertex centred data where restriction is an injection, this can also still be used for integer values. Otherwise this may be useful for data that are not needed in prolongation regions, but where the coarse grid has data worse than the fine grid, e.g. for constraints.
copy: Copy from the nearest neighbour instead of interpolating. This can likewise be used for integer data.
All other settings define actual prolongation operators.
-erik
On Mon, Oct 26, 2015 at 11:51 AM, Federico Guercilena < guercilena@th.physik.uni-frankfurt.de> wrote:
Hello,
could anyone tell me a few details regarding the Carpet prolongation operators? It appears there's no real documentation about them. Looking at Carpet source code I can see these operators are available:
none sync restrict copy Lagrange ENO ENOVOL WENO TVD Lagrange_monotone STAGGER011 STAGGER101 STAGGER110 STAGGER111
The "polynomial" ones (Lagrange, ENO, etc) appear to be self explanatory, more or less. I'm particularly interested in the exact behaviour of "none", "sync" and "copy". "none" and "sync" are the same thing apparently. I find the "restrict" operator very confusing, since these are supposed to take care of prolongation.
I'm asking because in a thorn I'm working on, a certain GF has prolongation set to "None". This resulted in buffer zones on finer grids not to be initialized (full of NaNs) when switching on mesh refinement. Although I think I found a workaround, I'd like to take care of this by using some already provided mechanism, if available.
Thank you very much, Federico Guercilena
-- Federico Guercilena Institut für Theoretische Physik Johann Wolfgang Goethe-Universität Max-von-Laue-Str. 1 60438 Frankfurt am Main, Germany Telephone: +49 69 798 47887 Email: guercilena[at]th.physik.uni-frankfurt.de
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