[R] squared euclidean distance

[Gavin Simpson]

On Wed, 2009-10-21 at 17:35 +0200, Caro B. wrote:
> Dear R-Help-Team,
> 
> 
> I would like to cluster my data using the ward-method. In several papers I
> read (e.g. Bahrenberg) that it is neccesary to use the "squared euclidean
> distance" with the ward-method. Unfortunatelly I cannot find this term in r
> as a method for measuring the distance.
> 
> Does anybody have an idea?

Compute the Euclidean distance then square the numbers to undo the sqrt
applied within dist.

set.seed(1)
dat <- data.frame(X1 = runif(10), X2 = runif(10))
d.euc <- dist(dat)
d.sqeuc <- d.euc^2
class(d.sqeuc) ## still a dist object

I have no idea what/who Bahrenberg is or whether/why it is advisable to
use this sq Euclidean with Ward's method; in my field I've seen Ward's
method used with all sorts of distance coefficients...

HTH

G

> 
> Thanks in advance,
> Carolin
> 
> 	[[alternative HTML version deleted]]
> 
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