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Eigensystem Bug? OS-X

• To: mathgroup at smc.vnet.net
• Subject: [mg56101] Eigensystem Bug? OS-X
• From: Erich Mueller <em256 at NOSPAM.cornell.edu>
• Date: Fri, 15 Apr 2005 04:47:56 -0400 (EDT)
• Organization: Cornell University
• Sender: owner-wri-mathgroup at wolfram.com

I have some strange behavior of Eigensystem and Eigenvectors [but not 
Eigenvalues] on my G5 running OS-X 10.3.8, and Mathematica 5.1.0.0.

The Kernel Hangs when I try to calculate the Eigenvectors of the 18x18 
Matrix at the end of this message. [Its the smallest matrix for which I 
have the problem.]  It does not respond to an "Abort Evaluation", or 
"Interupt Evaluation Signal", and I must kill it from the terminal.

There is no problem finding the eigenvalues of this same matrix on a PC. 
  Is there someone who can suggest a fix/workaround?  Failing that, is 
there anyone with a mac who can verify the problem?

Thanks,
Erich


{{-4., 1., 1., 1., 0., 0., 1., 0., 0., 0., 0. + 1.*I, 0. + 1.*I, 0. - 
1.*I, 0., 0., 0. - 1.*I, 0., 0.},
  {1., -4., 1., 0., 1., 0., 0., 1., 0., 0. + 1.*I, 0., 0. + 1.*I, 0., 0. 
- 1.*I, 0., 0., 0. - 1.*I, 0.},
  {1., 1., -4., 0., 0., 1., 0., 0., 1., 0. + 1.*I, 0. + 1.*I, 0., 0., 
0., 0. - 1.*I, 0., 0., 0. - 1.*I},
  {1., 0., 0., -4., 1., 1., 1., 0., 0., 0. - 1.*I, 0., 0., 0., 0. + 
1.*I, 0. + 1.*I, 0. - 1.*I, 0., 0.},
  {0., 1., 0., 1., -4., 1., 0., 1., 0., 0., 0. - 1.*I, 0., 0. + 1.*I, 
0., 0. + 1.*I, 0., 0. - 1.*I, 0.},
  {0., 0., 1., 1., 1., -4., 0., 0., 1., 0., 0., 0. - 1.*I, 0. + 1.*I, 0. 
+ 1.*I, 0., 0., 0., 0. - 1.*I},
  {1., 0., 0., 1., 0., 0., -4., 1., 1., 0. - 1.*I, 0., 0., 0. - 1.*I, 
0., 0., 0., 0. + 1.*I, 0. + 1.*I},
  {0., 1., 0., 0., 1., 0., 1., -4., 1., 0., 0. - 1.*I, 0., 0., 0. - 
1.*I, 0., 0. + 1.*I, 0., 0. + 1.*I},
  {0., 0., 1., 0., 0., 1., 1., 1., -4., 0., 0., 0. - 1.*I, 0., 0., 0. - 
1.*I, 0. + 1.*I, 0. + 1.*I, 0.},
  {0., 0. - 1.*I, 0. - 1.*I, 0. + 1.*I, 0., 0., 0. + 1.*I, 0., 0., 4., 
-1., -1., -1., 0., 0., -1., 0., 0.},
  {0. - 1.*I, 0., 0. - 1.*I, 0., 0. + 1.*I, 0., 0., 0. + 1.*I, 0., -1., 
4., -1., 0., -1., 0., 0., -1., 0.},
  {0. - 1.*I, 0. - 1.*I, 0., 0., 0., 0. + 1.*I, 0., 0., 0. + 1.*I, -1., 
-1., 4., 0., 0., -1., 0., 0., -1.},
  {0. + 1.*I, 0., 0., 0., 0. - 1.*I, 0. - 1.*I, 0. + 1.*I, 0., 0., -1., 
0., 0., 4., -1., -1., -1., 0., 0.},
  {0., 0. + 1.*I, 0., 0. - 1.*I, 0., 0. - 1.*I, 0., 0. + 1.*I, 0., 0., 
-1., 0., -1., 4., -1., 0., -1., 0.},
  {0., 0., 0. + 1.*I, 0. - 1.*I, 0. - 1.*I, 0., 0., 0., 0. + 1.*I, 0., 
0., -1., -1., -1., 4., 0., 0., -1.},
  {0. + 1.*I, 0., 0., 0. + 1.*I, 0., 0., 0., 0. - 1.*I, 0. - 1.*I, -1., 
0., 0., -1., 0., 0., 4., -1., -1.},
  {0., 0. + 1.*I, 0., 0., 0. + 1.*I, 0., 0. - 1.*I, 0., 0. - 1.*I, 0., 
-1., 0., 0., -1., 0., -1., 4., -1.},
  {0., 0., 0. + 1.*I, 0., 0., 0. + 1.*I, 0. - 1.*I, 0. - 1.*I, 0., 0., 
0., -1., 0., 0., -1., -1., -1., 4.}}

• Follow-Ups:
  • Re: Eigensystem Bug? OS-X
    • From: János <janos.lobb@yale.edu>
  • Re: Eigensystem Bug? OS-X
    • From: Sseziwa Mukasa <mukasa@jeol.com>