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Re: "ALOG2" ? (Ugly code follows) [message #14862]

Sat, 03 April 1999 00:00

luthi
Messages: 20
Registered: March 1999

Junior Member

Amara

wouldn't it be simpler to use the transformations for the base of a logaritm
described in any mathematics text?

log2(x) = ln(x)*log2(e)

(or in idl-language: alog2(x) = alog(x)*alog2(exp(1.0)) )

then you still have to calculate log2(e) but this is 1/ln(2), so the
simplyfied code looks like

function alog2, x
return, alog(x)/alog(2.0)
end ;{alog2}

(of course this works for any base)

hope this helps!

Martin

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Martin Luethi Tel. +41 1 632 40 92
Glaciology Section Fax. +41 1 632 11 92
VAW ETH Zuerich
CH-8092 Zuerich mail luthi@vaw.baum.ethz.ch
Switzerland
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		Re: "ALOG2" ? (Ugly code follows) By: luthi on Sat, 03 April 1999 00:00
		Re: "ALOG2" ? (Ugly code follows) By: Med Bennett on Sat, 03 April 1999 00:00

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