On Dec 23, 4:27 pm, ajaksu <aja... at gmail.com> wrote: > Is "x ** 0 > 0." instead of "atan2(x, -1.) > 0." unreliable across > platforms? x**0 doesn't distinguish between x = -0.0 and x = 0.0. I suspect you're confusing -0.0**0.0 with (-0.0)**0.0. Mark