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Re: implementation categories, exact rationals
| Date: Fri, 14 Oct 2005 15:26:46 -0400
| From: "John.Cowan" <jcowan@xxxxxxxxxxxxxxxxx>
| Aubrey Jaffer scripsit:
| > What is the rationale for mandating exact rationals? Over 15 years I
| > have written numerical Scheme code for everything from symbolic
| > algebra to Galois fields to linear systems to optics simulations
| > without needing exact rationals.
| > A case could be made if (expt -26. 1/3) returned -2.9624960684073702;
| > but I know of no Scheme implementation that does so.
| Why would that be desirable?
Because it is the cube root of -26. A better example is:
(expt -27 1/3) ==> -3
| (thus Chicken, and Petite Chez just adds a few more significant digits)
| is a more sensible value.