Rnl

rnl(x) is a pseudo-random number function used in NetHack when a result should be weighted by Luck.

rnl(x) has the same range as rn2(x) (that is, 0<=rnl(x)<x), but is weighted toward 0 if you have positive Luck, and toward x-1 if you have negative Luck.

Oliver Klozoff has provided an excellent tool for displaying a chart of the probabilities of the various probably outcomes of rnl(x) for each possible Luck score at http://klozoff.ms11.net/cgi-bin/nethack-rnl-calculator.pl