# Re: [R] resampling mean distances

From: Uwe Ligges <ligges_at_statistik.uni-dortmund.de>
Date: Tue 01 Aug 2006 - 18:17:40 EST

Jose Andres wrote:
> Hi all,
>
> I am trying to generate a distribution for the mean euclidean
> distance between a group of n elements in a given surface (the
> elements are randomly picked). Fo doing so I've written the
> following code:
>
> sampling<- function(x,size) {
>
> x<- x[sample(1:nrow(x),size),]
>
> mat<- matrix(c(x$V6,x$V7,x\$V8), ncol=3)
>
> mean.dist<- mean(dist(mat,"euclidean"))

# insert some return value such as:
return(mean.dist)

> }

Now replicate() the stuff, e.g.:

replicate(10000, sampling(x, 10))

Uwe Ligges

> x is the file where the data are stored
> size is the size of the group
> mat generates a simple matrix. V6, V7, and V8 are the 3D (x,y,z)
> coordinates of the group elements .
> mean.dist calculates the mean pairwise distance between the objects
> of the group.
>
> Everything works fine but I want to repeat this many times (e.g.
> 10000) and store the mean.dist values in a new variable so I can
> generate the distribution of mean pairwise distances of a group of
> size n in my surface.
>
> Is there any easy way to do this? I'd really appreciate all your
>
>
> /Jose
>
>
>
>
>
>
>
>
>
>
> On Jul 31, 2006, at 15:35, Prof Brian Ripley wrote:
>

>> On Mon, 31 Jul 2006, Sundar Dorai-Raj wrote:
>>
>>>
>>> LL wrote:
>>>> Hi.. I am running R version 2.3.1 on a Windows XP machine with
>>>> the latest Miktex 2.5 installed. I get no errors from R when
>>>> running the Sweave example,
>>>>
>>>> testfile <- system.file("Sweave", "Sweave-test-1.Rnw", package =
>>>> "utils")
>>>>
>>>> However, when I tex the resulting .tex file (after installing
>>>> a4.sty) I get the error below.
>>>>
>>>> This is pdfeTeX, Version 3.141592-1.30.6-2.2 (MiKTeX 2.5 RC 1)
>>>> entering extended mode
>>>> (Sweave-test-1.tex
>>>> LaTeX2e <2005/12/01>
>>>> Babel <v3.8g> and hyphenation patterns for english, dumylang,
>>>> nohyphenation, ge
>>>> ("C:\Program Files\MiKTeX 2.5\tex\latex\base\article.cls"
>>>> Document Class: article 2005/09/16 v1.4f Standard LaTeX document
>>>> class
>>>> ("C:\Program Files\MiKTeX 2.5\tex\latex\base\size10.clo"))
>>>> ("C:\Program Files\MiKTeX 2.5\tex\latex\ltxmisc\a4wide.sty"
>>>> ("C:\Program Files\MiKTeX 2.5\tex\latex\ntgclass\a4.sty"))
>>>> ! Missing \endcsname inserted.
>>>>                    \protect
>>>> l.11 \begin
>>>>            {document}
>>>> ?
>>>> 	[[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> R-help@stat.math.ethz.ch mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>>> This works for me. However, when I ran this, MiKTeX prompted me to
>>> install the ntgclass package, which I did. Everything ran smoothly
>>> after
>>> that. I'm using R-2.3.1 with MiKTeX 2.4 in WinXP Pro.
>> But he is using MiKTeX 2.5: looks like a problem with MiKTeX, as
>> the latex
>> error is in the initial processing.
>>
>> --
>> Brian D. Ripley,                  ripley@stats.ox.ac.uk
>> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
>> University of Oxford,             Tel:  +44 1865 272861 (self)
>> 1 South Parks Road,                     +44 1865 272866 (PA)
>> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>>
>> ______________________________________________
>> R-help@stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.


>
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