[R] Searching for antilog function

Duncan Murdoch murdoch at stats.uwo.ca
Wed Nov 24 20:31:41 CET 2004


On Wed, 24 Nov 2004 12:26:46 -0500, "Heather J. Branton" <hjb at pdq.com>
wrote :

>Dear R-users,
>
>I have a basic question about how to determine the antilog of a variable.
>
>Say I have some number, x, which is a factor of 2 such that x = 2^y. I 
>want to figure out what y is, i.e. I am looking for the antilog base 2 of x.
>
>I have found log2 in the Reference Manual. But I am struggling how to 
>get the antilog of that.

You seem to be confusing log with antilog, but log2(x) and 2^y are
inverses of each other, i.e.

log2(2^y) equals y

and 

2^log2(x) equals x

(up to rounding error, of course).

Duncan Murdoch




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