[R] svd and eigen
Stephane Dray
dray at biomserv.univ-lyon1.fr
Thu Sep 6 14:04:01 CEST 2001
Hello List,
i need help for eigen and svd functions. I have a non-symmetric
square matrix. These matrix is not positive (some eigenvalues are
negative). I want to diagonalise these matrix. So, I use svd and
eigen and i compare the results. eigen give me the "good" eigenvalues
(positive and negative). I compare with another software and the
results are the same. BUT, when i use svd, the results are completely
different (no sign and not the same value). I thought that svd is a
generalisation of eigen for non-square matrices but apparently, there
are more differences ?
I 've R1.2.3 on W2000.
Thanks in advance.
--
Stéphane DRAY
---------------------------------------------------------------
Biométrie et Biologie évolutive - Equipe "Écologie Statistique"
Universite Lyon 1 - Bat 711 - 69622 Villeurbanne CEDEX - France
Tel : 04 72 43 27 56 Fax : 04 78 89 27 19
04 72 43 27 57 E-mail : dray at biomserv.univ-lyon1.fr
---------------------------------------------------------------
ADE-4 http://pbil.univ-lyon1.fr/ADE-4/ADE-4F.html
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