Alexander Belopolsky <belopol...@users.sourceforge.net> added the comment:
On Tue, May 11, 2010 at 10:19 PM, Alexander Belopolsky <rep...@bugs.python.org> wrote: .. > Similarly, while unlikely to improve performance, I would prefer not > to use any bit-trick implementation of ilog2 (in a separate function, > of course) instead of calling floating point log2. In my head, an > assignment of floating point result to an integer variable always > raises a red flag. > Searching for relevant past issues, I've come across a similar sentiment from Mark: """ floor(log(n, 2)) is poor code. This is not supposed to be a dramatic statement, just a statement of fact. Its correctness is dependent on minute details of floating point. It is poor code in exactly the same way that "while x < 1.0: x += 0.1" is poor code---behaviour in boundary cases is almost entirely unpredictable. """ - msg78066 - Mark Dickinson - I also noticed that the reference implementation does not require this calculation because the loop is implemented recursively. Did you find recursive implementation to give worse performance? ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue8692> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
