R help - Apr 2003 - clustering

Dear R-users,

I have a two - dimensional data set which needs to be clustered into
groups:
I'm searching for groups of points which show a positive
correlation (in a twodimensional plot of the data set), but I do not have
any knowledge about how many groups there might be.
Do you know of a clustering algorithm in R (or
in general) which can use a-priori information about the cluster's shape,
in particular that the points of a given cluster should lie on a line?
The "EMclust" algorithm does allow to chose a general shape, such as
"elliptical" for example. However, this method proved not to be
successful.

Thank you very much,
Yours sincererly

Philip

Dear Philip,

as you have already suggested, mclust would be the first choice. Did you
try to run EMclust with emModelNames="VEV"? If you send me the data, I
can
take a look at it and see what went wrong.

There is also methodology for clusterwise linear regression (CLR), where the
points of a cluster lie on a line, but there is a distinction between
dependent and independent variable, which may or may not be what you
want. As far as I know, there is nothing for CLR on CRAN, but my R-package
fpc contains a function fixreg for linear regression fixed point clusters
(reference Hennig, Journal of Classification 19, 249-276 (2002)). It can be
obtained under
http://www.math.uni-hamburg.de/home/hennig/fixreg/fixreg.html

Furthermore I have a program for ML-estimation of linear regression
mixtures (reference deSarbo and Cron, Journal of Classification 5, 249-282 
(1988)), but undocumented and for private use. Ask me if you are
interested.

Best,
Christian

On Wed, 23 Apr 2003 EdwardSeelefant at aol.com wrote:
> Dear R-users,
> 
> I have a two - dimensional data set which needs to be clustered into
> groups:
> I'm searching for groups of points which show a positive
> correlation (in a twodimensional plot of the data set), but I do not have
> any knowledge about how many groups there might be.
> Do you know of a clustering algorithm in R (or
> in general) which can use a-priori information about the cluster's
shape,
> in particular that the points of a given cluster should lie on a line?
> The "EMclust" algorithm does allow to chose a general shape, such
as
> "elliptical" for example. However, this method proved not to be
> successful.
> 
> Thank you very much,
> Yours sincererly
> 
> Philip
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> 
-- 
***********************************************************************
Christian Hennig
Seminar fuer Statistik, ETH-Zentrum (LEO), CH-8092 Zuerich (currently)
and Fachbereich Mathematik-SPST/ZMS, Universitaet Hamburg
hennig at stat.math.ethz.ch, http://stat.ethz.ch/~hennig/
hennig at math.uni-hamburg.de, http://www.math.uni-hamburg.de/home/hennig/
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ich empfehle www.boag.de