-# These functions hide the difference between 0-origin and 1-origin addressing.
-def VALID_QUADRANT(x, y): return ((x)>=0 and (x)<GALSIZE and (y)>=0 and (y)<GALSIZE)
-def VALID_SECTOR(x, y): return ((x)>=0 and (x)<QUADSIZE and (y)>=0 and (y)<QUADSIZE)
-