Mark Dickinson added the comment: No: IEEE-754r and the C99 standard both say clearly that atanh(1) should be infinity and atanh(-1) should be -infinity, and furthermore that the 'divide-by-zero' exception should be raised rather than the 'invalid' exception. It's a singularity, just like log(0). (This makes even more sense viewed from the perspective of complex arithmetic, where atanh is defined at all points in the complex plane except -1 and 1, where it has log-type singularities.)
The general idea is that it's meaningful to set atanh(1) = infinity because that's what the limit of atanh(x) is as x approaches 1 from below; similarly for atanh(-1) and log(0). __________________________________ 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
