> > It would be instructive to understand how much, if any, python code > > would break if we lost -0.0. I'm do not believe that there is any > > reliable way for python code to tell the difference between all of > > the different types of IEEE 754 zeros and in the special case of -0.0 > > the best test I can come up with is repr(n)[0]=='-'. Is there an > > compelling case, to do with compatibility or otherwise, for exposing > > the sign of a zero? It seems like a numerical anomaly to me. > > I think it is reasonable to admit that > a) this change is a change in semantics for the majority of the > machines > b) it is likely that this change won't affect a significant number > of applications (I'm pretty sure someone will notice, though; > someone always notices).
If you're really going to bother doing this rather than just adding a note in the docs about testing for and reusing the most common float values to save memory when instantiating them from external input: Just do a binary comparison of the float with predefined + and - 0.0 float values or any other special values that you wish to catch rather than a floating point comparison. -g _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
