Message-ID: <l9o9q0lm2j1fi046pb3irlo1vhfcv76v9l@4ax.com>
Date: 2004-11-24T19:31:41Z
From: Duncan Murdoch
Subject: Searching for antilog function
In-Reply-To: <41A4C456.308@pdq.com>
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