11 Jan
2008
11 Jan
'08
12:03 p.m.
On Fri, Jan 11, 2008 at 02:54:20PM +0100, Achim Schneider wrote:
+-0 / +-0 is always NaN 'cos you can't tell which one is bigger and thus can't decide between positive and negative Infinity, and it isn't both, either.
But then there's +0/0 and -0/0, which would be +Infinity and -Infinity, and +0 > 0 > -0. AFAIK there are no floats with three zero values, though.
No, +0/0 might be 0 or finite instead of +Infinity, so it's a NaN. e.g. consider Prelude> let x=1e-300/1e300 Prelude> x 0.0 Prelude> x/x NaN The "true" answer here is that x/x == 1.0 (not 0 or +Infinity), but there's no way for the computer to know this, so it's NaN. -- David Roundy Department of Physics Oregon State University