[Scipy-tickets] [SciPy] #1543: Problem in btdtri

SciPy Trac scipy-tickets@scipy....
Sun Oct 30 21:51:47 CDT 2011


#1543: Problem in btdtri
----------------------------+-----------------------------------------------
  Reporter:  ezander        |       Owner:  pv         
      Type:  defect         |      Status:  closed     
  Priority:  normal         |   Milestone:  Unscheduled
 Component:  scipy.special  |     Version:  0.8.0      
Resolution:  invalid        |    Keywords:             
----------------------------+-----------------------------------------------
Changes (by warren.weckesser):

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


Old description:

> btdtri(0.5, 0.5, 0.5) returns nan and complains about an invalid value,
> while all parameters are perfectly legal. If you go an ulp up or down
> with any of the parameters the function works as expected. Only if all of
> them are exactly 0.5.
>
> >>> import scipy.special
> >>> scipy.special.btdtri(0.5,0.5,0.5)
> Warning: invalid value encountered in btdtri
> nan

New description:

 btdtri(0.5, 0.5, 0.5) returns nan and complains about an invalid value,
 while all parameters are perfectly legal. If you go an ulp up or down with
 any of the parameters the function works as expected. Only if all of them
 are exactly 0.5.
 {{{
 >>> import scipy.special
 >>> scipy.special.btdtri(0.5,0.5,0.5)
 Warning: invalid value encountered in btdtri
 nan
 }}}

--

Comment:

 Thanks for reporting the problem.  It has already been fixed:
 {{{
 In [1]: import scipy

 In [2]: scipy.__version__
 Out[2]: '0.9.0'

 In [3]: from scipy.special import btdtri

 In [4]: btdtri(0.5, 0.5, 0.5)
 Out[4]: 0.49999999999999967

 }}}

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1543#comment:1>
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