#1222: Reduction weight for periodic domains. -------------------------+-------------------------------------------------- Reporter: bentivegna | Owner: eschnett Type: defect | Status: new Priority: minor | Milestone: Component: Carpet | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by eschnett):
When vertex centering is used, then each of the boundary points contributes with weight 1/2 to the reduction, as explained above. If I interpret the patch correctly, then it essentially shifts the domain by 1/2 grid point in the periodic directions, so that one boundary point contributes with weight 1 and the other with weight 0. Given that one boundary point has a shiftout of 0 and the other has a shiftout of 1, this will then use exactly the interior points and ignore all points set by the periodic boundary condition.
I wonder what this domain-shifting does when several refinement levels are used, since each level would be shifted by a different amount, depending on the grid spacing. With many refinement levels, there can be many finest grid points in the region where the coarsest grid has been shifted.
Another way of obtaining the same effect would be to use cell-centred refinement. In this case, there are no grid cells with weight 1/2; all cells have either weight 0 or weight 1.