Mark Dickinson added the comment: George: I think my last post was a bit rude. I apologize if it came across that way.
Mathematical rigor and IEEE-754 recommendations aren't necessarily in conflict here, though. For example, the natural log function from (0, infinity) to (-infinity, infinity) extends naturally and uniquely to a continuous function on the closed subset [0, infinity] of the extended real line---i.e., the real line together with the two extra points -infinity and infinity. With the appropriate topology, the extended real line is a perfectly well-defined and well-behaved mathematical object, though of course it's no longer a field. Since IEEE-754 floats include infinities, it's reasonable, and sometimes useful, to regard the set of IEEE-floats as a computational model of the extended real line instead of the reals. At any rate, I agree with you that log(0) and atanh(1) should raise Python exceptions, at least for now. But these calculations are qualitatively different from log(-1) and atanh(2), and it wouldn't be at all unreasonable if they raised a different exception--- e.g. ZeroDivisionError instead of ValueError. __________________________________ Tracker <[EMAIL PROTECTED]> <http://bugs.python.org/issue1640> __________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
