From: transfire@...
Date: 2006-07-24T00:07:16+09:00
Subject: Re: Infinity


hadley wickham wrote:
> > Facets has Infinity (actaully it was deprecated for a while until I
> > fixed. Your post inspired me to fix it, so it's now back in the very
> > latest version. Thanks!)
>
> That's great!  Thanks.
>
> > It uses the constant INFINITY. Is that cool? Or is there some sort of
> > general practice of using Inf?
>
> I think Inf is more common: R uses it, so does MATLAB
> (http://www.mathworks.com/access/helpdesk/help/techdoc/ref/inf.html),
> and there's a PEP for python that uses it
> (http://www.python.org/dev/peps/pep-0754/, which also has a nice
> discussion of these issues)

Nice, that was helpful. I added some query methods to Numeric, eg.
finite?, infinite?, ... and did this:

  UNDEFINED = InfinityClass.instance(0)
  INFINITY  = InfinityClass.instance(1)

  NaN = UNDEFINED
  Inf = INFINITY
  PosInf = INFINITY
  NegInf = -INFINITY

Thanks!
T.