R help - Jun 2010 - prcomp() and the lenght of PC:s

Hi,

I would like to know whether there is some deeper rationale behind or is it just
an established practice that the lenghts of principal components, giving for
example by prcomp-function, are normalised to 1?

Best regards,

Atte Tenkanen
University of Turku, Finland
Department of Musicology
+35823335278
http://users.utu.fi/attenka/

What do you mean by 'lenght'?  It is part of the definition that the 
coefficient vector has Euclidean length one: a principal component is 
a projection.  See for example MASS p.302.

I don't see anything that has length 1 in the R sense.

On Wed, 16 Jun 2010, Atte Tenkanen wrote:
> Hi,
>
> I would like to know whether there is some deeper rationale behind 
> or is it just an established practice that the lenghts of principal 
> components, giving for example by prcomp-function, are normalised to 
> 1?
>
> Best regards,
>
> Atte Tenkanen
> University of Turku, Finland
> Department of Musicology
> +35823335278
> http://users.utu.fi/attenka/
>
> ______________________________________________
> 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.
>
-- 
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)
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