From ripley at stats.ox.ac.uk  Sat Dec 16 08:01:51 2006
From: ripley at stats.ox.ac.uk (Prof Brian Ripley)
Date: Sat, 16 Dec 2006 07:01:51 +0000 (GMT)
Subject: [Rd] possible bug in co.intervals when overlap=0
In-Reply-To: <45833121.4080701@stat.purdue.edu>
References: <45833121.4080701@stat.purdue.edu>
Message-ID: <Pine.LNX.4.64.0612160656080.32578@gannet.stats.ox.ac.uk>

This happens equally when overlap = 0.5 (the default).

Yes, it is a bug.  R does xr <- x[r + ii] with fractional r.

On Fri, 15 Dec 2006, Benjamin Tyner wrote:

> I apologize if this is just a misunderstanding on my part, but I was
> under the impression that the intervals returned by co.intervals should
> cover all the observations. Yet
>
> x<-1:10
> z<-co.intervals(x,overlap=0)
>
> In R, z equals
>      [,1] [,2]
> [1,]  0.5  1.5
> [2,]  2.5  3.5
> [3,]  3.5  4.5
> [4,]  5.5  6.5
> [5,]  7.5  8.5
> [6,]  8.5  9.5
>
> Note in particular the second and last element of x are not covered by
> any of the intervals. In fact S-PLUS gives
>     [,1] [,2]
> [1,]    1    2
> [2,]    3    3
> [3,]    4    5
> [4,]    6    7
> [5,]    8    8
> [6,]    9   10


-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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[Rd] possible bug in co.intervals when overlap=0
Prof Brian Ripley