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Re: About the bits reserved for float variable [message #39497]

Sat, 22 May 2004 05:01

George N. White III is currently offline

George N. White III
Messages: 56
Registered: September 2000

Member

On Fri, 21 May 2004, Nuno Oliveira wrote:

> I looking at the Chapter 5 of the Bulding Aplication.
>
> It says, for float variables that it's a 32 bits number in the range of
> +/-10^38 withe approximately six or seven decimal places of significance.
> What I'm missing here? How can a number 32 bit number range between -10^38
> and +10^38?

Read chapter 1 of any decent introductory numerical analysis text and then
"What Every Computer Scientist Should Know About Floating-Point
Arithmetic" by D. Goldberg, ACM Computing Surveys, Vol 23, 1991, p5-48)
and reprinted in Sun's online manuals. See links on:

http://cch.loria.fr/documentation/IEEE754/

While it is true that many people do get by without understanding
f.p. arithmetic, there are also many examples of calculations going astray
due to failure to recognize situations where the difference between
f.p. and real numbers matters. It is becoming more important to
understand the material in Goldberg's paper because newer hardware
speedups (speculative execution, merged operations, parallel
processing) tend to make it harder to diagnose arithmetic problems.

--
George N. White III <aa056@chebucto.ns.ca>

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[Message index]

		Re: About the bits reserved for float variable By: George N. White III on Sat, 22 May 2004 05:01
		Re: About the bits reserved for float variable By: Kenneth P. Bowman on Fri, 21 May 2004 15:22
		Re: About the bits reserved for float variable By: David Fanning on Fri, 21 May 2004 08:07
		Re: About the bits reserved for float variable By: James Kuyper on Fri, 21 May 2004 08:00
		Re: About the bits reserved for float variable By: Paul Van Delst[1] on Fri, 21 May 2004 07:44
		Re: About the bits reserved for float variable By: Chris Lee on Fri, 21 May 2004 07:36
		Re: About the bits reserved for float variable By: Nuno Oliveira on Tue, 25 May 2004 10:08

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