[Octave-bug-tracker] [bug #29829] eigvalues are incorrect

[nos]

URL:
  <http://savannah.gnu.org/bugs/?29829>

                 Summary: eigvalues are incorrect
                 Project: GNU Octave
            Submitted by: nosnos
            Submitted on: Sat 08 May 2010 10:24:21 PM GMT
                Category: None
                Severity: 3 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: nos
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.3
        Operating System: GNU/Linux

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Details:

eig(rho) gives singular values something like (it even varies from time to
time)

  -7.1985e+167
   -2.2305e-03
    2.2305e-03
   7.1985e+167

while matlab gives 

   0.0250
   0.0250
   0.0250
   0.9250

The matrix rho is constructed as follows
                                            

I = sqrt(-1);

t0 = eye(2);

t1 = [0 1;
      1 0];
t2 = [0 -I;
      I  0];
t3 = [1  0;
      0 -1];

m1 = [t1,zeros(2);zeros(2),t1];
m2 = [t2,zeros(2);zeros(2),t2];
m3 = [t3,zeros(2);zeros(2),t3];
m4 = [zeros(2),eye(2);eye(2),zeros(2)];
m5 = [zeros(2),t1;t1,zeros(2)];
m6 = [zeros(2),t2;t2,zeros(2)];
m7 = [zeros(2),t3;t3,zeros(2)];
m8 = [zeros(2),-I*eye(2);I*eye(2),zeros(2)];
m9 = [zeros(2),-I*t1;I*t1,zeros(2)];
m10 = [zeros(2),-I*t2;I*t2,zeros(2)];
m11 = [zeros(2),-I*t3;I*t3,zeros(2)];
m12 = [eye(2),zeros(2);zeros(2),-eye(2)];
m13 = [t1,zeros(2);zeros(2),-t1];
m14 = [t2,zeros(2);zeros(2),-t2];
m15 = [t3,zeros(2);zeros(2),-t3];

n=[   0.0011057
  -0.1341262
   0.8377961
   0.6086926
   0.0829238
  -0.2919701
   0.6070342
  -0.1736753
   0.2884966
   0.0829238
  -0.1736753
  -0.5649987
  -0.0011057
  -0.1263867
  -0.6271805
];



rho = (eye(4) +
n(1)*m1+n(2)*m2+n(3)*m3+n(4)*m4+n(5)*m5+n(6)*m6+n(7)*m7+n(8)*m8+n(9)*m9+n(10)*m10+n(11)*m11+n(12)*m12+n(13)*m13+n(14)*m14+n(15)*m15)/4





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