Re: error: `eig' undefined near line 5 column 7

[Henry F. Mollet]

Others have replied and resolved emacs problems. Here are the eight
solutions (eigenvalues) to your matrix and I suggest that it is not a
symmetric matrix as can be seen by inspection. In addition, all eigenvalues
would be real for a symmetric matrix. It looks as if your matrix is inverse
symmetric, but I'm not familiar with such terminology.
Henry
A =

  1.00000  0.14300  0.33300  9.00000  0.16700  0.20000  0.50000  0.25000
  7.00000  1.00000  0.20000  9.00000  0.33300  0.14300  5.00000  4.00000
  3.00000  5.00000  1.00000  5.00000  0.25000  0.16700  1.00000  3.00000
  0.11100  0.11100  0.20000  1.00000  0.14300  0.12500  0.12500  0.20000
  6.00000  3.00000  4.00000  7.00000  1.00000  2.00000  0.50000  4.00000
  5.00000  7.00000  6.00000  8.00000  0.50000  1.00000  0.33300  0.33300
  2.00000  0.20000  1.00000  8.00000  2.00000  3.00000  1.00000  1.00000
  4.00000  0.25000  0.33300  5.00000  0.25000  3.00000  1.00000  1.00000

octave:2> foo = eig(A)
foo =

   11.72374 +  0.00000i
   -1.05925 +  5.81855i
   -1.05925 -  5.81855i
   -0.00571 +  2.32593i
   -0.00571 -  2.32593i
   -2.03018 +  0.00000i
    0.21818 +  0.82953i
    0.21818 -  0.82953i


on 7/30/04 5:49 PM, Rich Shepard at address@hidden wrote:

> I'm brand-new at using octave. I need to calculate the principal
> eigenvector for a symetrical matrix. For the moment, it's 8x8. The installed
> version of octave is 2.1.35; I downloaded 2.1.71 yesterday but haven't yet
> upgraded.
> 
> I wrote a short shell script:
> 
> #! /usr/bin/octave -pf
> # calculate eigenvector for Columbia Gateway scoping.
> A = [1.000,0.143,0.333,9.000,0.167,0.200,0.500,0.250;
> 7.000,1.000,0.200,9.000,0.333,0.143,5.000,4.000;
> 3.000,5.000,1.000,5.000,0.250,0.167,1.000,3.000;
> 0.111,0.111,0.200,1.000,0.143,0.125,0.125,0.200;
> 6.000,3.000,4.000,7.000,1.000,2.000,0.500,4.000;
> 5.000,7.000,6.000,8.000,0.500,1.000,0.333,0.333;
> 2.000,0.200,1.000,8.000,2.000,3.000,1.000,1.000;
> 4.000,0.250,0.333,5.000,0.250,3.000,1.000,1.000];
> foo = eig(A);
> 
> When I run it this is what I see:
> 
> address@hidden ~]$ ./gateway.oct
> GNU Octave, version 2.1.35 (i386-redhat-linux-gnu).
> Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001 John W. Eaton.
> This is free software with ABSOLUTELY NO WARRANTY.
> For details, type arranty'.
> 
> *** This is a development version of Octave.  Development releases
> *** are provided for people who want to help test, debug, and improve
> *** Octave.
> ***
> *** If you want a stable, well-tested version of Octave, you should be
> *** using one of the stable releases (when this development release
> *** was made, the latest stable version was 2.0.16).
> 
> error: ig' undefined near line 5 column 7
> error: evaluating index expression near line 5, column 7
> error: evaluating assignment expression near line 5, column 5
> 
> What have I missed?
> 
> Thanks,
> 
> Rich



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