#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 bentivegna):
If I understand your argument correctly, I do not agree. Let's say we have a periodic domain where we identify x=+1 with x=-1; we cover this with two grids, one with spacing dx=0.2 and one with dx/2, and with a lower shiftout of 1 and an upper shiftout of 0. With three boundary points, this will look like this:
{{{ -1 +1 | | | | | | B B B I I I I I I I I I I B B B b b b i i i i i i i i i i i i i i i i i i i i b b b }}}
The coordinate of the last internal point will indeed be different on the two levels (0.8 on the coarse and 0.9 on the fine), but things like the volume of the two levels (assigning weight of 1 to the interior points and 0 otherwise) is the same:
C: #I*dx=10*0.2=2 F: #i*dx/2=20*0.1=2
Notice that the volume of the two levels is the same with the current weight assignment too -- the patched code produces identical results as the current one, when the boundaries have been correctly set. It only makes a difference when the boundaries are junk, in which case it prevents this junk from polluting the reduction operations.