[R] prcomp() and the lenght of PC:s

[Prof Brian Ripley]

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/
>
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-- 
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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