[R] weird behaviour of eigen() (actual example)

[Prof Brian Ripley]

That is not a symmetric matrix so the eigenvalues are potentially complex 
and are sorted by modulus.  There's an ambiguity in the description for 
that case.

In all cases the eigenvectors are in the same order as the eigenvalues.

On Mon, 10 Nov 2003, Karim Elsawy wrote:

> Hi Thomas, 
> the matrix V , which produced the anomelous order,is attached as a text
> file,
> V<-matrix(scan("V.dat"),ncol=40,byrow=T)
> eigen(V)$values
> 
> best regards
> karim
> 
> Martin Maechler wrote:
> > 
> > >>>>> "Karim" == Karim Elsawy <elsawy at ysbl.york.ac.uk>
> > >>>>>     on Mon, 10 Nov 2003 08:34:07 +0000 writes:
> > 
> >     Karim> Hi Thomas, the matrix V , which produced the
> >     Karim> anomelous order,is attached as an R object,
> > 
> > and it wasn't :
> > Most binary attachments are *not* allowed on our mailing lists
> > (for several reasons I'd rather not discuss on R-help)
> > and the mailman software silently drops them.
> > Either send these only to individuals, give the R code to
> > generate them, give an URL (ftp://.. or http://.. ) where people
> > can get it; post the result of  dput(...), or if you must, use plain/text
> > attachments e.g. from save(..., ascii=TRUE).
> > 
> > Martin Maechler <maechler at stat.math.ethz.ch>    http://stat.ethz.ch/~maechler/
> > Seminar fuer Statistik, ETH-Zentrum  LEO C16    Leonhardstr. 27
> > ETH (Federal Inst. Technology)  8092 Zurich     SWITZERLAND
> > phone: x-41-1-632-3408          fax: ...-1228                   <><

-- 
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