[Scipy-tickets] [SciPy] #552: linalg.svd fails for some matrices [Win32, SciPy 0.6.0, NumPy 1.0.4]

SciPy scipy-tickets@scipy....
Thu Dec 6 13:47:22 CST 2007


#552: linalg.svd fails for some matrices [Win32, SciPy 0.6.0, NumPy 1.0.4]
--------------------------+-------------------------------------------------
 Reporter:  phinrichs     |       Owner:  somebody
     Type:  defect        |      Status:  new     
 Priority:  normal        |   Milestone:  0.7     
Component:  scipy.linalg  |     Version:          
 Severity:  major         |    Keywords:  svd     
--------------------------+-------------------------------------------------
 The attached script enters an infinite loop with SciPy 0.6.0 and NumPy
 1.0.4 on Python 2.5 on Windows: it locks up and consumes 100% of available
 CPU after printing "Now computing SVD of H". The script runs to completion
 on other machines with other versions of NumPy and SciPy.

 This particular matrix is not the only one which crashes linalg.svd, but
 just one test case which consistently and repeatedly demonstrates the
 problem.

 I have tested a few version combinations of SciPy, NumPy, and Python, and
 the behavior depends heavily on versions of SciPy and NumPy that are
 installed:
  * Works: Linux (Debian etch), Python 2.4, SciPy 0.5.2, NumPy 1.0.1
  * Works: Windows, Python 2.5, SciPy 0.5.2.1, NumPy 1.0.1
  * Works: Windows, Python 2.5, SciPy 0.6.0, NumPy 1.0.3.1
  * Fails: Windows, Python 2.5, SciPy 0.5.2.1, NumPy 1.0.4
  * Fails: Windows, Python 2.5, SciPy 0.6.0, NumPy 1.0.4

 The behavior seems most dependent on the version of NumPy installed, even
 though linalg.svd is a SciPy function -- I'm not sure why this is.

 I can provide further testing if needed.

-- 
Ticket URL: <http://scipy.org/scipy/scipy/ticket/552>
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