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## output from eig() is complex?

**From**: |
John W. Eaton |

**Subject**: |
output from eig() is complex? |

**Date**: |
Fri, 19 Jul 1996 15:19:59 -0500 |

On 19-Jul-1996, Mario Storti <address@hidden> wrote:
: I want to compute the eigenvalues of a symmetric matrix and sort them
: as real numbers but I don't obtained the expected result. For
: instance:
:
: octave:7> A=rand(10);
: octave:8> A=A+A';
: octave:9> sort(eig(A))
: ans =
:
: 0.0089208
: 0.5152296
: -0.5608954
: -0.6509429
: 0.9682804
: 1.5698353
: 1.9441555
: -2.0148139
: -2.5246725
: 9.5114825
:
: My interpretation is that Octave is sorting the vector by absolute
: value since this is the action for complex numbers, and in general the
: result from the eig() operation should be a list of complex
: numbers.
Correct.
The problem is that Octave 1.1.1 doesn't do automatic type conversions
in some places that it should. This problem should be fixed in the
next release.
Thanks,
jwe