Alexander Belopolsky <[EMAIL PROTECTED]> added the comment: Mark,
I noticed that you replaced a call to _PyLong_AsScaledDouble with your round to nearest algorithm. I wonder if _PyLong_AsScaledDouble itself would benefit from your change. Currently it is used in PyLong_AsDouble and long_true_divide. I would think that long_true_divide would be more accurate if longs were rounded to the nearest float. I also wonder whether round to nearest float can be implemented without floating point arithmetics. I would think round towards zero should be a simple matter of extracting an appropriate number of bits from the long and round to nearest would at most require a long addition. I believe _PyLong_AsScaledDouble is written the way it is to support non-IEEE floating formats, but I am not sure that your algorithm would always return the nearest float on an arbitrary non-IEEE platform. Maybe it would be worthwhile to provide a simple IEEE specific code with well specified semantics for both PyLong_AsDouble and long_true_divide, but fall back to the current code on non-IEEE platforms. ---------- nosy: +belopolsky _______________________________________ Python tracker <[EMAIL PROTECTED]> <http://bugs.python.org/issue3166> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
