Re: Looking for a fast exp(x) where -10.0<=x<=10.0

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Article #1039

#1039

From: Craig Hansen
Date: Fri, 02 Nov 1990 03:17

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In article <1990Nov1.184820.5796@walt.disney.com>, scott@walt.disney.com (Scott Watson) writes:
> I have a need for an fast exp(x) function...
> Any ideas?

Decompose your exp(x) into exp(a+b), where a and b are
the most-significant and least significant parts of x.
exp(a+b)=exp(a)*exp(b), so get exp(a) and exp(b) from
two small tables and multiply them together.

Regards,
Craig Hansen
craig@microunity.com

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!apple!netcom!craig
From: craig@netcom.UUCP (Craig Hansen)
Newsgroups: comp.dsp,sci.math.num-analysis
Subject: Re: Looking for a fast exp(x) where -10.0<=x<=10.0
Summary: decompose exp(x) into exp(a+b)=exp(a)*exp(b)
Keywords: exp fast functions lookup tables
Message-ID: <16020@netcom.UUCP>
Date: 2 Nov 90 03:17:33 GMT
References: <1990Nov1.184820.5796@walt.disney.com>
Followup-To: comp.dsp
Organization: Netcom- The Bay Area's Public Access Unix System {408 241-9760 guest}
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