Hi Bj�rn-Helge,
Thanks for your help.
In my case, there are more variables in the matrix than the units,
so I have to use Prcomp with covariance to do PCA. The problem I am facing
is how to get fisrt 8 coefficients and scores and how to write the result
into text file. Thanks again.
When I change princomp to prcomp below, I will NULL for pc$scores
& pc$loadings.
X <- some matrix
pc <- prcomp(X)
pc$scores[,1:4] # The four first score vectors
pc$loadings[,1:4] # The four first loadings
Best Regards,
WeiQiang Li
[EMAIL PROTECTED] (Bj�rn-Helge Mevik)
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02/25/2005 05:38 PM
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Re: [R] How to set up number of prin comp.
> I am trying to use PrinComp to do principle component analysis.
I
> would like to know how to set the number of principle components.
I assume you mean the function princomp (case _does_ matter in R) in
package stats (which is loaded by default). This function has no way
of specifying how many components to calculate; it always gives you
all components. You have to select the components you want
afterwards. See help(princomp) for details. E.g.
X <- some matrix
pc <- princomp(X)
pc$scores[,1:4] # The four first score vectors
pc$loadings[,1:4] # The four first loadings
(The loadings can also be extracted with loadings(pc)[,1:4] .)
--
Bj�rn-Helge Mevik
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