Message-ID: <20040522094921.A98721058C@slim.kubism.ku.dk>
Date: 2004-05-22T11:49:23Z
From: Duncan Murdoch
Subject: Inaccurate and Inconsistent results from 'round' function (PR#6905)
On Sat, 22 May 2004 06:34:14 +0200 (CEST), jkbreaux@san.rr.com wrote:
>Full_Name: Jim Breaux
>Version: 1.9.0
>OS: WinXP
>Submission from: (NULL) (209.78.110.135)
>
>
>According to the help for 'round' it is supposed to round to the even digit.
>However, see the following examples:
This is not a bug. The problem is that floating point types do not
represent all decimal values exactly, so when you say
> round(40.3655, 3)
[1] 40.365
you are actually rounding a number which is slightly smaller than
40.3655. The rounding works as advertised on exactly representable
numbers:
> round(0.25,1)
[1] 0.2
> round(0.75,1)
[1] 0.8
Duncan Murdoch