[Scipy-tickets] [SciPy] #963: arpack.eigen gives incorrect result

SciPy Trac scipy-tickets@scipy....
Sat Dec 4 15:15:31 CST 2010


#963: arpack.eigen gives incorrect result
----------------------------------+-----------------------------------------
  Reporter:  kyleabeauchamp       |       Owner:  wnbell
      Type:  defect               |      Status:  closed
  Priority:  normal               |   Milestone:  0.9.0 
 Component:  scipy.sparse.linalg  |     Version:  0.7.0 
Resolution:  fixed                |    Keywords:        
----------------------------------+-----------------------------------------
Changes (by pv):

  * status:  new => closed
  * resolution:  => fixed


Comment:

 Fixed in r6987 and r6988

 It works correctly now:
 {{{
 >>> from scipy.sparse.linalg import eigs
 >>> import numpy as np
 >>> A = np.loadtxt('Matrix.dat')
 >>> w2,v2 = eigs(A.T,k=5,which="SM")
 Traceback (most recent call last):
 ...
 scipy.sparse.linalg.eigen.arpack.arpack.ArpackNoConvergence: ARPACK error
 -1: No convergence (501 iterations, 3/5 eigenvectors converged)
 >>> w2,v2 = eigs(A.T,k=5,which="SM",maxiter=2000)
 >>> w,v = np.linalg.eig(A.T)
 >>> print np.sort(abs(w2))[:5]
 [ 0.00013061  0.00018592  0.00125313  0.0018528   0.00274987]
 >>> print np.sort(abs(w))[:5]
 [ 0.00013061  0.00018592  0.00125313  0.0018528   0.00274987]
 }}}

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/963#comment:2>
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