[R] princomp with more coloumns than rows: why not?

[Spencer Graves]

Have you considered "svd"? 

hope this helps.  spencer graves

Liaw, Andy wrote:

>In the `Detail' section of ?princomp:
>
>princomp only handles so-called Q-mode PCA, that is feature extraction of
>variables. If a data matrix is supplied (possibly via a formula) it is
>required that there are at least as many units as variables. For R-mode PCA
>use prcomp. 
>
>
>Andy
>
>  
>
>>-----Original Message-----
>>From: bhx2 at mevik.net [mailto:bhx2 at mevik.net] 
>>Sent: Thursday, October 16, 2003 5:14 AM
>>To: r-help at stat.math.ethz.ch
>>Subject: [R] princomp with more coloumns than rows: why not?
>>
>>
>>As of R 1.7.0, princomp no longer accept matrices with more 
>>coloumns than rows.  I'm curious:  Why was this decision made?
>>
>>I work a lot with data where more coloumns than rows is more 
>>of a rule than an exception (for instance spectroscopic 
>>data).  To me, princomp have two advantages above prcomp: 1) 
>>It has a predict method, and 2) it has a biplot method.
>>
>>A biplot method shouldn't be too difficult to implement (I 
>>believe I've seen one on R-help).
>>
>>A predict method seems to be more difficult, because the 
>>prcomp object doesn't include the means that need to be 
>>subtracted from the new data.  Would it break conformance 
>>with S to let prcomp return the means as well?
>>
>>-- 
>>Sincerely,
>>Bjørn-Helge Mevik
>>
>>______________________________________________
>>R-help at stat.math.ethz.ch mailing list 
>>https://www.stat.math.ethz.ch/mailman/listinfo> /r-help
>>
>>    
>>
>
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