Re: [R] cluster.stats

From: Christian Hennig <chrish_at_stats.ucl.ac.uk>
Date: Sat, 14 Jun 2008 18:09:11 +0100 (BST)

The given information is not enough to tell you what's going on. as.dist doesn't appear in the given code and it's not clear to me what kind of object img is ("a small image" doesn't tell me what R makes of it). Also, try to read the help pages first and find out whether img is of the format that is required by the functions. And check (using str for example) whether "data" is what you expect it to be.

Christian

On Sat, 14 Jun 2008, Laura Poggio wrote:

> Thank you very much for your answer.
> I tried to run the function on my data and now I am getting this message of
> error
> Error in as.dist(dmat[clustering == i, clustering == i]) : (subscript)
> logical subscript too long
>
> Below the code I am using (version2.7.0 of R with all packages updated):
>
> data <- <- as(img, "data.frame")[1:1] #(where img is a small image 256 px
> x 256 px)
> kl <- kmeans(data, 5)
> library(fpc)
> cluster.stats(data, kl$cluster)
>
> Thank you for any hints on the reasons and meaning of the error!
>
> Laura
>
>
>
>
>
> 2008/6/13 Christian Hennig <chrish_at_stats.ucl.ac.uk>:
>
>> Dear Laura,
>>
>> Dear list,
>>> I just tried to use the function cluster.stat in the package fpc.
>>> I just have a couple of questions about the syntax:
>>>
>>> cluster.stats(d,clustering,alt.clustering=NULL,
>>> silhouette=TRUE,G2=FALSE,G3=FALSE)
>>>
>>> 1) the distance object (d) is an object obtained by the function dist() on
>>> my own original matrix?
>>>
>>
>> d is allowed to be an object of class dist or a dissimilarity matrix.
>> The answer to your question depends on what your "original matrix" is. If
>> it is something on which you can compute a distance by dist(), you're right,
>> at least if dist() delivers the distance you are interested in.
>>
>> 2) clustering is the clusters vector as result of one of the many
>>> clustering
>>> methods?
>>>
>>
>> The help page tells you what clustering can be. So it could be the
>> clustering/partition vector of a clustering method or it could be something
>> else. Note that cluster.stats doesn't depend on any particular clustering
>> method. It computes the statistics regardless of where the clustering vector
>> comes from.
>>
>> Best regards,
>> Christian
>>
>>
>>> Thank you very much in advance and sorry for such basic question, but I
>>> did
>>> not manage to clarify my mind.
>>>
>>> Laura
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ______________________________________________
>>> R-help_at_r-project.org 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.
>>>
>>>
>> *** --- ***
>> Christian Hennig
>> University College London, Department of Statistical Science
>> Gower St., London WC1E 6BT, phone +44 207 679 1698
>> chrish@stats.ucl.ac.uk, www.homepages.ucl.ac.uk/~ucakche<http://www.homepages.ucl.ac.uk/%7Eucakche>
>>
>


R-help_at_r-project.org 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. Received on Sat 14 Jun 2008 - 17:11:11 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Sat 14 Jun 2008 - 19:30:45 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive