I don't claim that it is a new or unsolved problem. I know that there is some code in Warren's book "Hacker's Delight". http://en.wikipedia.org/wiki/Hacker%27s_Delight An algorithm was also described in Eugene McDonnell's September 1980 Recreational APL column. http://www.jsoftware.com/papers/eem/qq111.htm
Beyond the Roger Moore idea in EEM's article, there is an additional trick that gets you another factor of 3 to 4. I forget whether "Hacker's Delight" has that additional trick. (It probably does.) I Google "sum of bits" (with the quotes) but I don't see anything on the first page of hits that is obviously a discussion on +/b . ----- Original Message ----- From: Jack Andrews <[email protected]> Date: Monday, September 6, 2010 20:41 Subject: Re: [Jprogramming] Splitting an integer into its digits To: Programming forum <[email protected]> > > For example, how do you compute +/b where b is a bit-boolean vector? > > google "sum of bits" > > :) ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
