[Scipy-tickets] [SciPy] #787: Spurious inf from scipy.special.hyp1f1(0, -k, z)

SciPy scipy-tickets@scipy....
Sun Nov 9 19:09:00 CST 2008


#787: Spurious inf from scipy.special.hyp1f1(0, -k, z)
---------------------------+------------------------------------------------
 Reporter:  pv             |       Owner:  somebody
     Type:  defect         |      Status:  new     
 Priority:  normal         |   Milestone:  0.8     
Component:  scipy.special  |     Version:  devel   
 Severity:  minor          |    Keywords:          
---------------------------+------------------------------------------------
 hyp1f1(a=0, b, z) yields infs at points which are poles for a != 0:
 {{{
 >>> s.hyp1f1(0, -0.99999, 0)
 1.0
 >>> s.hyp1f1(0, -1, 0)
 inf
 >>> s.hyp1f1(0, -1.00001, 0)
 1.0
 }}}
 It would make sense to continue hyp1f1(0, b, z) to unity with all b, z for
 a=0. See eg.
 http://functions.wolfram.com/HypergeometricFunctions/Hypergeometric1F1/03/01/03/0003/
 -- this convention is used also by Mathematica.

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Ticket URL: <http://scipy.org/scipy/scipy/ticket/787>
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