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 <[EMAIL PROTECTED]>:
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
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*** --- ***
Christian Hennig
University College London, Department of Statistical Science
Gower St., London WC1E 6BT, phone +44 207 679 1698
[EMAIL PROTECTED],
www.homepages.ucl.ac.uk/~ucakche<http://www.homepages.ucl.ac.uk/%7Eucakche>
*** --- ***
Christian Hennig
University College London, Department of Statistical Science
Gower St., London WC1E 6BT, phone +44 207 679 1698
[EMAIL PROTECTED], www.homepages.ucl.ac.uk/~ucakche
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
