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

From: Prof Brian Ripley <ripley_at_stats.ox.ac.uk>
Date: Wed, 16 Jun 2010 14:56:51 +0100 (BST)

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)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

______________________________________________
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.
Received on Wed 16 Jun 2010 - 14:00:04 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Wed 16 Jun 2010 - 14:20:32 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.

list of date sections of archive