[Scipy-tickets] [SciPy] #869: stats.invnorm.cdf returns NaNs with low mu values

SciPy Trac scipy-tickets@scipy....
Mon Feb 7 06:58:59 CST 2011


#869: stats.invnorm.cdf returns NaNs with low mu values
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 Reporter:  jpaalasm     |       Owner:  somebody    
     Type:  defect       |      Status:  needs_review
 Priority:  normal       |   Milestone:  0.10.0      
Component:  scipy.stats  |     Version:  devel       
 Keywords:               |  
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Comment(by josefpktd):

 Raising an exception on invalid arguments is inconsistent with the current
 design of the distributions.

 Currently the distribution classes check for goodargs (valid arguments)
 and return values for those arguments and nan for the invalid arguments.
 And it's therefore up to the caller to check and treat nans.

 In this case, the nans are a result of the calculations instead of a
 violation of _argcheck, but for strict inequality constraints on
 parameters like mu>0, there might be more cases like this.

 So, I think returning nans is the consistent answer, although numerical
 precision could be improved.

 invnorm has been deprecated and renamed to invgauss in scipy 0.9

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/869#comment:4>
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