In article <[EMAIL PROTECTED]>, Grant Edwards <[EMAIL PROTECTED]> writes: |> |> I assume the "you" in that sentence refers to the IEEE FP |> standards group. I just try to follow the standard, but I have |> found that the behavior required by the IEEE standard is |> generally what works best for my applications.
Well, it could be, but actually it was a reference to the sentence "This makes sense since such is the limit of division by a quantity that goes to zero." |> I do real-world engineering stuff with measured physical |> quatities. There generally is no such thing as "true zero". It is extremely unusual for even such programs to use ONLY continuous interval scale quantities, but they might dominate your usage, I agree. Such application areas are very rare, but do exist. For example, I can tell that you don't use statistics in your work, and therefore do not handle events (including the analysis of failure rates). |> > I fully agree that infinity arithmetic is fairly well-defined for |> > most operations, but it most definitely is not in this case. It should |> > be reserved for when the operations have overflowed. |> |> All I can say is that 1/0 => Inf sure seems to work well for me. Now, can you explain why 1/0 => -Inf wouldn't work as well? I.e. why are ALL of your zeroes, INCLUDING those that arise from subtractions, are known to be positive? If you can, then you have a case (and an EXTREMELY unusual application domain. If you can't, then I am afraid that your calculations are unreliable, at best. The point here is that +infinity is the correct answer when the zero is known to be a positive infinitesimal, just as -infinity is when it is known to be a negative one. NaN is the only numerically respectable result if the sign is not known, or it might be a true zero. Regards, Nick Maclaren. -- http://mail.python.org/mailman/listinfo/python-list
