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Mail Archives: djgpp/2001/05/22/08:45:03

Message-ID: <3B0A09EC.3EB10991@acm.org>
From: Eric Sosman <esosman AT acm DOT org>
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Subject: Re: Generating Exponents FAST!
References: <0q9kgtgddkvj69od8094172vodtrpubgsh AT 4ax DOT com> <9edet9$hev$1 AT nets3 DOT rz DOT RWTH-Aachen DOT DE>
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Date: Tue, 22 May 2001 11:37:25 GMT
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Hans-Bernhard Broeker wrote:
> 
> Radical NetSurfer <radsmail AT juno DOT com> wrote:
> 
> >  pow(10, ep);  is one obvious approach
> 
> > Which requires the time and computational overhead of whatever
> > is involved in  pow() function....
> 
> ... which may easily be faster than anything you could come up with.
> Go figure before you make blind assumptions about the quality of
> library code --- you do have access to all the sources, so why not
> peek into them to check for yourself?
> 
> > IS THERE A MORE DIRECT ROUTE to generating 10 ^ ep?
> 
> Of course: e.g. to not generate them at all. Precompute a table of
> such values, if you really only need so few of them.

    Or for a computational approach, see Knuth "The Art of Computer
Programming, Volume II: Seminumerical Algorithms," section 4.6.3.

-- 
Eric Sosman
esosman AT acm DOT org

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