title: eigenvectors from numpy.eig not orthogonal
body: <p>my problem is the following: using scipy.linalg.eig to get eigenvectors and eigenvalues i see that all my eigenvalues have multiplicity 1 yet when i run the code below it doesn't confirm that the eigenvectors are orthogonal as they should be in this case. any reason why this would be? or how to fix it?</p>
  
  <pre><code>import scipy as SP
  import numpy as NP
  from scipy import linalg
  from numpy import linspace,asscalar,argsort
  import cmath
  import time
  
  matA=SP.array([[-0.0001, 0., 0., 0.00001, 0., 0., 0.00002, 0.],[0., -0.0002, 0., 
    0., 0., 0., 0., 0.],[0., 0., -0.00015, 0., 0., -9.*10**-6, 
    0., -0.00005],[0.00001, 0., 0., -0.0001, 0., 0.00001, 1.*10**-6, 
    0.],[0., 0., 0., -5.*10**-6, -0.0001, 0., 0., 0.],[0., -9.*10**-6, 
    0., 0.00001, 0., -0.0002, 0., 0.00005],[0., 0., 0., 0.00002, 0., 
    0., -0.0001, 0.],[0., 0.00004, 0., 0., 0., 0.00005, 0., -0.00015]])
  
  matB=SP.array([[0., 0., 0., 0., 0., 0., 0., 0.],[0., 0., 1.5*10**-10, 0., 0., 0., 
    0., 0.],[0., -1.5*10**-10, 0., 0., 0., 0., 0., 0.],[0., 0., 0., 0.,
     0., 0., 0., 0.],[0., 0., 0., 0., 0., 3.*10**-10, 0., 0.],[0., 0., 
    0., 0., -3.*10**-10, 0., 2.*10**-10, 0.],[0., 0., 0., 0., 
    0., -2.*10**-10, 0., 0.],[0., 0., 0., 0., 0., 0., 0., 0.]])
  
  matdim=len(matB[0])
  
  #coefficient matrix for original ODE
  def matM(x):
      return matA+(x**2)*matB
  
  #define sorted eigensystem function
  def eigsys(x):
      evs,EVS=linalg.eig(matM(x),check_finite=False)
      absevs=abs(evs)
      idx=argsort(absevs)[::-1]
      evs=evs[idx]
      EVS=EVS[:,idx]
      return (evs,EVS)
  
  #check for orthogonality
  eigvecs=SP.transpose(eigsys(60000)[1])
  for j in range(8):
      for i in range(8):
          print SP.vdot(eigvecs[i],eigvecs[j])
  
  #show eigenvalues all have multiplicity 1
  print eigsys(60000)[0]  
  </code></pre>