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Re: information on Eigensystem

  • To: mathgroup at
  • Subject: [mg33614] Re: information on Eigensystem
  • From: Alois Steindl <Alois.Steindl+e325 at>
  • Date: Wed, 3 Apr 2002 18:08:19 -0500 (EST)
  • Organization: Inst. f. Mechanics II, TU Vienna
  • References: <a890u0$nto$> <a8br2m$3lg$> <a8e6sd$7k9$>
  • Sender: owner-wri-mathgroup at

Bettina <bho at> writes:

> Hi
> I have another question concerning Eigensystem: I try to get the 
> Eigensystem for heritian (complex) matrices. Following my test matrix 
> M={{65,3+6i,12-6i,4-2i},{3-6i,30,0,30},{12+6i,0,9,3},{4+2i,30,3,46}}.
> But if I try to get Eigensystem[M] nothing comes up. What could be the 
> problem? I have already found out (archive) that there seem to be some 
> special effects when using Eigensystem on complex matrices, but these 
> messages dated from 1999 and 2000. Has anything changed since then? Is 
> there a way to solve my problem?
> Thanks for help
> Bettina

the imaginary unit is written as capital I in Mathematica.
Even if you set i=I, Eigensystem[M] returns a very long result,
which might be of little use. If you only need the numbers, you could
try Eigensystem[N[M]].

Good luck

Alois Steindl,                  Tel.: +43 (1) 58801 / 32558      
Inst. for Mechanics II,         Fax.: +43 (1) 58801 / 32598
Vienna University of Technology,
A-1040 Wiedner Hauptstr. 8-10   Email: Alois.Steindl+e325 at

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