Repository : ssh://darcs.haskell.org//srv/darcs/packages/containers On branch :
http://hackage.haskell.org/trac/ghc/changeset/0e43f11acced853f96fa7d8a4a68efd7744b3797 >--------------------------------------------------------------- commit 0e43f11acced853f96fa7d8a4a68efd7744b3797 Author: Joachim Breitner <[email protected]> Date: Sun Sep 18 17:14:23 2011 +0200 bitcount source reference >--------------------------------------------------------------- Data/DenseIntSet.hs | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/Data/DenseIntSet.hs b/Data/DenseIntSet.hs index d500a18..a8ffdd2 100644 --- a/Data/DenseIntSet.hs +++ b/Data/DenseIntSet.hs @@ -1199,7 +1199,15 @@ highestBitSet n0 = ----------------------------------------------------------------------} {---------------------------------------------------------------------- - [bitcount] as posted by David F. Place to haskell-cafe on April 11, 2006 + [bitcount] as posted by David F. Place to haskell-cafe on April 11, 2006, + based on the code on + http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan, + where the following source is given: + Published in 1988, the C Programming Language 2nd Ed. (by Brian W. + Kernighan and Dennis M. Ritchie) mentions this in exercise 2-9. On April + 19, 2006 Don Knuth pointed out to me that this method "was first published + by Peter Wegner in CACM 3 (1960), 322. (Also discovered independently by + Derrick Lehmer and published in 1964 in a book edited by Beckenbach.)" ----------------------------------------------------------------------} bitcount :: Int -> Word -> Int bitcount a 0 = a _______________________________________________ Cvs-libraries mailing list [email protected] http://www.haskell.org/mailman/listinfo/cvs-libraries
