>>>>> "Robert" == Robert Dodier <robert.dodier at gmail.com> writes:
Robert> COMPLEX-ATANH applies the identity arg(x - y i) = - arg(x + y i)
Robert> but that fails if y = 0 and x < 0. So I plugged in a special case for y = 0.
I think there needs to be more discussion about this. Some Lisps
support signed zeroes (cmucl, sbcl), others do not. Maxima's
bigfloats don't support signed-zeroes.
What are we going to do about that? I think that is a bigger issue
because when we've answered that, then we will know better about what
we want for the branch cuts.
Ray