Fw: [R] SIMCA algorithm implementation

[Liaw, Andy]

SIMCA, I believe, is Svante Wold's invention, and extensively used in the
chemometrics area (analysis of data from analytic chemistry).  My vague
impression of what it does is PCA in the individual classes.  I have not
been able to locate a detail description of the algorithm.  (I'd appreciate
it very much if some one can help.)  One feature of the methodology that
distinguish it from others, I believe, is its ability to classify new
observations as belonging to classes other than what appeared in the
training data.

Contribution from it's author?  Fat chance.  Svante sells (stand-alone)
SIMCA at a premium price.

Best,
Andy


> -----Original Message-----
> From: Thomas W Blackwell [mailto:tblackw at umich.edu] 
> Sent: Wednesday, October 15, 2003 10:53 AM
> To: Mike White
> Cc: R-help at stat.math.ethz.ch
> Subject: Re: Fw: [R] SIMCA algorithm implementation
> 
> 
> Mike  -
> 
> For predicting class membership, I would use either  lda() or
> qda()  from the MASS package.  See the Venables and Ripley
> book for detailed description of the methods.  You'll have
> to rely on your own references for what the 'SIMCA' algorithm 
> actually does.  I've never heard of it.  Sounds like some 
> sort of discriminant analysis to me.  Maybe its authors would 
> like to contribute an implementation of it to R.
> 
> -  tom blackwell  -  u michigan medical school  -  ann arbor  -
> 
> On Wed, 15 Oct 2003, Mike White wrote:
> 
> > I have used PCA for data classification by visual 
> examination of the 
> > 3D scatter plot of the first 3 principal components.  I now want to 
> > use the results to predict the class for new data.  I have used 
> > predict.princomp to predict the scores and then visualise 
> the results 
> > on a 3D scatter plot using the rgl library.  However, is there an R 
> > function that will fit the new data to the class 
> assignments derived 
> > from PCA?  I think this is similar to what the SIMCA algoirthm does.
> >
> > Thanks
> > Mike
> >
> > ----- Original Message -----
> > From: "Mike White" <mikewhite.diu at tiscali.co.uk>
> > To: <R-help at stat.math.ethz.ch>
> > Sent: Wednesday, October 08, 2003 9:25 AM
> > Subject: Re: [R] SIMCA algorithm implementation
> >
> >
> > > Dear All
> > > Is there a SIMCA (Soft Independent Modelling Class Analogy) 
> > > implementation on R or does anyone know if is it possible to 
> > > replicate the SIMCA
> > algorithm
> > > using existing R functions?
> > >
> > > Thanks
> > > Mike White
> >
> 
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