[Tim Peters] >> ... >> >>> (-math.inf) ** 3.1 >> inf
[David Mertz] > Weird. I take it that's what IEEE-754 says. NaN would sure be more intuitive > here since inf+inf-j is not in the domain of Reals. Well, technically > neither is inf, but at least it's the limit of the domain. :-). Mathematical reals have all sorts of properties floats fail to capture, while mathematical reals don't distinguish between -0 and +0 at all. "Practical' symmetry arguments often underlie what float standards require. At heart , the rules for infinite arguments are often _consequences_ of "more obvious" rules for signed zero arguments, following from replacing +-inf with 1/+-0 in the latter. More explanation here: https://stackoverflow.com/questions/10367011/why-is-pow-infinity-positive-non-integer-infinity But we're not required to _like_ it; we just have to implement it ;-) >> >>> (-math.inf) ** 3.0 # NOTE THIS ONE >> -inf >> >>> (-math.inf) ** 2.9 >> inf _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
