implementation categories, exact rationals Aubrey Jaffer (14 Oct 2005 18:29 UTC)
Re: implementation categories, exact rationals John.Cowan (14 Oct 2005 19:26 UTC)
Re: implementation categories, exact rationals Aubrey Jaffer (14 Oct 2005 19:38 UTC)
Re: implementation categories, exact rationals John.Cowan (14 Oct 2005 20:16 UTC)
Re: implementation categories, exact rationals bear (16 Oct 2005 18:08 UTC)
Re: implementation categories, exact rationals Michael Sperber (17 Oct 2005 07:44 UTC)
Re: implementation categories, exact rationals Aubrey Jaffer (17 Oct 2005 21:59 UTC)
Re: implementation categories, exact rationals Bradley Lucier (17 Oct 2005 22:07 UTC)

Re: implementation categories, exact rationals John.Cowan 14 Oct 2005 19:26 UTC

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?  1.48124803420369+2.5655968538523i
(thus Chicken, and Petite Chez just adds a few more significant digits)
is a more sensible value.

--
John Cowan <xxxxxx@reutershealth.com> www.ccil.org/~cowan  www.reutershealth.com
Micropayment advocates mistakenly believe that efficient allocation of
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systems, not their goal.  The reasons markets work are not because users
have embraced efficiency but because markets are the best place to allow
users to maximize their preferences, and very often their preferences are
not for conservation of cheap resources.  --Clay Shirkey