A = [3 2 -1; 0 0 1; 7 7 0]
A =
     3     2    -1
     0     0     1
     7     7     0
[V,D] = eig(A)
V =
   0.0752 - 0.2718i   0.0752 + 0.2718i   0.4268          
  -0.3449 + 0.1525i  -0.3449 - 0.1525i  -0.5570          
  -0.8822            -0.8822             0.7124          
D =
   2.1395 + 0.9463i        0                  0          
        0             2.1395 - 0.9463i        0          
        0                  0            -1.2790          
abs(D(1,1))
ans =
    2.3394
diary off