[R] resampling mean distances

[Uwe Ligges]

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  
> comments.
> 
> Thanks in advance,
> 
> /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
>>>> rman, ngerman, french, loaded.
>>>> ("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.
>>>> <to be read again>
>>>>                    \protect
>>>> l.11 \begin
>>>>            {document}
>>>> ?
>>>> 	[[alternative HTML version deleted]]
>>>>
>>>> ______________________________________________
>>>> R-help at stat.math.ethz.ch mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide http://www.R-project.org/posting- 
>>>> 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 at 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 at stat.math.ethz.ch mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting- 
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.