Function healpixRingToNest( k, ringIndex )

Description:
Converts a healpix tile index from the RING to the NEST scheme at a given order.

Note: the ringIndex parameter is 0-based, unlike the table row index special token $index (a.k.a. $0), which is 1-based. So if the HEALpix index is implicitly determined by the table row, the value $index-1 should be used.

Parameters:
k (integer)
HEALPix order (0..29)
ringIndex (long integer)
pixel index in RING scheme
Return Value (long integer):
pixel index in NEST scheme
See Also:
HEALPix web site
Signature:
long healpixRingToNest(int, long)