[R] body of non-visible function

Prof Brian Ripley ripley at stats.ox.ac.uk
Thu May 5 17:28:40 CEST 2005

getS3method("princomp", "default").

The first of these is in the See Also of ?methods.

On Thu, 5 May 2005, Anna Oganyan wrote:

> Hello,
> Is there any possibility in R to see the body of the 
> function, for
> example 
> If I do :
>> methods(princomp)
> so, I get that princomp.default and princomp.formula are non-visible 
> functions and
> body(princomp.default) doesnt show it.
> In particular, I guess I have a very naïve question&
> Id like to see how scores calculation is implemented in the function
> princomp. Because when I multiply my data matrix on the matrix of loadings
>> data.matrix %*% princomp(data.matrix, scores=T)$loadings
> I get different result than just doing
>> princomp(data.matrix, scores=T)$scores.

You have forgotten to centre your data.  It may be more helpful to look at 
the predict method.

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

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