Re: Eigensystem: different solution in V5.0 and V4.1 ??
- To: mathgroup at smc.vnet.net
- Subject: [mg48311] Re: Eigensystem: different solution in V5.0 and V4.1 ??
- From: ivo.bleylevens at facburfdaw.unimaas.nl (Ivo bleylevens)
- Date: Sun, 23 May 2004 06:15:37 -0400 (EDT)
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- Sender: owner-wri-mathgroup at wolfram.com
Hello again ! This is in addition to my message earlier. I forgot to say (maybe the most important part of my message) that the eigenvalues Mathematica 5.0 calculates, are the correct eigenvalues when the notebook is ran at a AMD Athlon 1200 MHz or AMD Duron 800 MHz PC and not on a Pentium4 2,6 GHz stand-alone machine and a Pentium4 3,06 HT notebook !! So: Mathematica 5.0 produces only the right solutions of Eigensystem when you don't use a Pentium 4 processor ??? Greetings Ivo Bleylevens ivo.bleylevens at facburfdaw.unimaas.nl (Ivo bleylevens) wrote in message news:<c8mu5a$8nu$1 at smc.vnet.net>... > Hello all ! > > I am a dutch PhD student at the University of Maastricht and I have a > question about some strange behaviour of the Mathematica's 5.0 > function Eigensystem. I have an 512x512 non-symmetric complex matrix > M. When i use the command eigsys = Eigensystem[M] in Mathematica 5.0, > the eigenvalues were not the eigenvalues I expected ! I calculated > exactly the same notebook in Mathematica version 4.1 and these > eigenvalues look the same as the wanted eigenvalues !! Am i doing > something wrong in version 5.0 ?? > > * I already tried to use the options of Eigensystem described at > http://documents.wolfram.com/v5/Built-inFunctions/AdvancedDocumentation/LinearAlgebra/4.4.html > but that also didn't help. > > * I tried to set the precision of Mathematica 5.0 with the command > eigsys = Eigensystem[N[M, 30]] but that didn't help either ! > > * I also calculated the eigenvalues of the matrix M with another system using > the functions EIG and EIGS (which makes use op the LAPACK functions. > Mathematica 5 uses this functions also as described in the link > above). The eigenvalues computed with this two functions are exactly > similar with the eigenvalues calculated in Mathematica 4.1.... > > So in my opinion Mathematica 5.0 produces incorrect > eigenvalues......can someone help me ??? > > Ivo Bleylevens > Universiy of Maastricht