[Scipy-tickets] [SciPy] #759: errors in special.hyp2f1 for some values as used in stats.rdist

SciPy scipy-tickets@scipy....
Fri Oct 24 14:52:48 CDT 2008


#759: errors in special.hyp2f1 for some values as used in stats.rdist
---------------------------+------------------------------------------------
 Reporter:  josefpktd      |       Owner:  somebody
     Type:  defect         |      Status:  new     
 Priority:  normal         |   Milestone:          
Component:  scipy.special  |     Version:          
 Severity:  normal         |    Keywords:          
---------------------------+------------------------------------------------
 see Ticket #758: error in stats.rdist.cdf

 source of error is incorrect special.hyp2f1 for some values:

 special.hyp2f1(....)

 {{{
 hyp2f1 parameters:  0.5 0.5 1.5 0.5625
 hyp2f1   1.13074943864
 correct  1.13074943864

 hyp2f1 parameters:  0.5 -4.0 1.5 0.5625
 hyp2f1   0.539109148298
 correct  0.539109148298

 hyp2f1 parameters:  0.5 -49.0 1.5 0.5625
 hyp2f1   0.167526839266
 correct  0.167526838691
 0.167527 verified with
 http://functions.wolfram.com/webMathematica/FunctionEvaluation.jsp?name=Hypergeometric2F1

 hyp2f1 parameters:  0.5 -74.0 1.5 0.5625
 hyp2f1   0.136673757067
 correct  0.136671154918

 hyp2f1 parameters:  0.5 -99.0 1.5 0.5625
 hyp2f1   -0.578130627609                    #wrong
 correct  0.118311386286

 hyp2f1 parameters:  0.5 -149.0 1.5 0.5625
 hyp2f1   -2002388188.0                    #wrong
 correct  0.0965606007742
 0.0965606 (Wolfram research)

 hyp2f1 parameters:  0.5 -199.0 1.5 0.5625
 hyp2f1   -7.80882500777e+018                    #wrong
 correct  0.0836065135116
 0.0836065 (Wolfram research)
 }}}

 correct values above are calculated with stats.rdist.veccdf

 Josef

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Ticket URL: <http://scipy.org/scipy/scipy/ticket/759>
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