[Scipy-tickets] [SciPy] #889: arpack.eigen gives wrong answer when k = 1
SciPy Trac
scipy-tickets@scipy....
Tue Apr 20 19:01:41 CDT 2010
#889: arpack.eigen gives wrong answer when k = 1
---------------------------------+------------------------------------------
Reporter: kyleabeauchamp | Owner: wnbell
Type: defect | Status: new
Priority: normal | Milestone: 0.8.0
Component: scipy.sparse.linalg | Version: 0.7.0
Keywords: |
---------------------------------+------------------------------------------
Comment(by ysr):
Please check the eigenvalues for k=1, k=2. If the two eigenvalues are the
same (i.e., repeated), then note that the eigenvectors for repeated
eigenvalues can be anything in the linear subspace spanned by the two
eigenvectors. For example, if a matrix has two zero eigenvalues with
eigenvectors (unnormalized) [2,2,2,-3,-3] and [2,2,2,3,3], they can also
be reported as [0,0,0,0,0] and [0,0,0,1,1].
This stuff only happens for repeated eigenvalues.
--
Ticket URL: <http://projects.scipy.org/scipy/ticket/889#comment:3>
SciPy <http://www.scipy.org>
SciPy is open-source software for mathematics, science, and engineering.
More information about the Scipy-tickets
mailing list