#181: AEILocalInterp should not off-centre the interpolation stencil by default ---------------------+------------------------------------------------------ Reporter: hinder | Owner: Type: defect | Status: confirmed Priority: major | Milestone: Component: Cactus | Version: Resolution: | Keywords: AEILocalInterp ---------------------+------------------------------------------------------
Comment (by eschnett):
With periodic boundaries, which grid points are boundary points and which ones are evolved? Where are the grid points placed with respect to the boundary? There are basically three options: (1) an evolved grid point on the lower boundary, (2) an evolved grid point on the upper boundary, and (3) grid points staggered about the boundary. The two former go with vertex centred refinement, the latter with cell centred refinement.
Where is the boundary located according to AEILocalInterp? If this thorn assumes that the boundary is directly at the outermost evolved grid point, then this notion clashes with what CoordBase chooses (see above), as boundary according to CoordBase will necessarily be located further outwards. Thus you might need to all off-centring the stencil, simply because AEILocalInterp's notion of what off-centring means is different from CoordBase's notion.
Thorn CoordBase has some nice sketches explaining things that I tried to explain above.