From: Kaspar Schiess <eule@...>
Date: 2012-10-26T15:19:38+09:00
Subject: Re: bit count or bit set

Hei Charles,

Any number of these bit twiddling hacks here:
	http://www-graphics.stanford.edu/~seander/bithacks.html

will translate straight to Ruby. I guess the lookup table approach is
easy to implement and reasonably fast.

Another strategy would be to implement this in C and load it as an
extension. Make sure this is really the hotspot of your code before
optimizing...

kaspar