[Scipy-tickets] [SciPy] #1530: Cauchy fit returns nothing in scipy 0.9.0

SciPy Trac scipy-tickets@scipy....
Wed Oct 5 13:07:32 CDT 2011


#1530: Cauchy fit returns nothing in scipy 0.9.0
------------------------------+---------------------------------------------
 Reporter:  gtg944q           |       Owner:  somebody   
     Type:  defect            |      Status:  new        
 Priority:  normal            |   Milestone:  Unscheduled
Component:  scipy.stats       |     Version:  0.9.0      
 Keywords:  cauchy fit stats  |  
------------------------------+---------------------------------------------
 Hello.  I am attempting to fit the cauchy distribution to data in scipy,
 but am receiving errors.  I have verified that my code works in an older
 version of python and scipy (also on a different platform- sorry, this is
 the only other option I have available).  I'll copy and paste below my
 sessions with the python terminal.  Please let me know if you need any
 additional information.  Thanks!

 New version, not functioning:
 Python 2.7.2 (default, Jun 12 2011, 15:08:59) [MSC v.1500 32 bit (Intel)]
 on win
 32
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import scipy
 >>> print scipy.version.version
 0.9.0
 >>> import scipy.stats as stats
 >>> print stats.cauchy.fit(stats.cauchy.rvs(size=200))
 C:\Python27\lib\site-packages\scipy\stats\distributions.py:1737:
 RuntimeWarning:
  invalid value encountered in double_scalars
   Lhat = muhat - Shat*mu
 (nan, 0.0)
 >>> print stats.cauchy.fit(stats.norm.rvs(size=200))
 (nan, 0.0)
 >>> print stats.cauchy.fit(stats.cauchy.rvs(size=200))
 (nan, 0.0)
 >>> print stats.cauchy.fit(stats.cauchy.rvs(size=200))
 (nan, 0.0)
 >>>

 Older version, works:
 Python 2.4.5 (#4, Apr 12 2008, 09:09:16)
 [GCC 3.4.1] on sunos5
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import scipy
 >>> print scipy.version.version
 0.4.7.1617
 >>> import scipy.stats as stats
 >>> print stats.cauchy.fit(stats.cauchy.rvs(size=200))
 [ 0.04395272  0.89676901]
 >>> print stats.cauchy.fit(stats.norm.rvs(size=200))
 [ 0.02706823  0.59303574]

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1530>
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