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From: Rahul Jain <rj...@sid-1129.sid.rice.edu>
Newsgroups: comp.lang.lisp
Subject: Re: very large reals?
Date: 20 Feb 2002 13:10:47 -0600
Organization: Rice University, Houston TX
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Deepak Goel <de...@glue.umd.edu> writes:

> While (Expt 100 100) is okay with CL, why deosn't (expt 100.0 100.0)
> return something useful?

Because your floating point representation can't, probably.

> why can't the exponent-parts of the reals be allowed to be as high as
> it gets?

> It's like: CL frees you from upper limits on numbers (as compared to,
> say C) when dealing with integers but not when dealing with reals..

They are, but you're using floats, which are a specific type of real.

> or did i miss something obvious?  or is there a package or some other
> way that allows the exponent-part to get as large as it wants to ?  

if you want arbitrary-precision exact fraction arithmetic, try
rationals, but I don't think expt will return a rational...

Floating point arithmetic is fixed-range-precision inexact fraction
arithmetic. The range and precision of floating point is a function of
the size of the type you're using. (expt 100.0d0 100.0d0) _might_ work
better.

-- 
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