On Fri, Mar 23, 2012 at 03:48:20PM -0400, Andrew Robbins wrote: > Peter, > > I hope this isn't considered too off-topic, but Mathematica has 4 > distinct infinities. > The usual Infinity (+inf.0 in Scheme), -Infinity (-inf.0 in Scheme), > and the following: > > - ComplexInfinity (might be represented in Scheme as (make-polar > +inf.0 +nan.0)), and
What about the negative version of this one? > - DirectedInfinity[z] (might be represented in Scheme as (make-polar > +inf.0 (angle z))). Same question here. And what about (make-polar +nan.0 +nan.0)? If I'm asking stupid questions, pardon my ignorance. I don't really know anything about complex numbers. > If y is an exact number, then (imag-part (log ...)) should also be exact. > I'm not sure how many Scheme implementations actually store exact polar > complex numbers this way, but it helps keep numbers exact. I wonder about that too. Even Gambit doesn't represent exact polar complex numbers exactly. Perhaps John could provide a list of Schemes that do. Cheers, Peter -- http://sjamaan.ath.cx -- "The process of preparing programs for a digital computer is especially attractive, not only because it can be economically and scientifically rewarding, but also because it can be an aesthetic experience much like composing poetry or music." -- Donald Knuth _______________________________________________ Scheme-reports mailing list [email protected] http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports
