[Scipy-tickets] [SciPy] #1398: problem with numpy 0's in stats.poisson.rvs

SciPy Trac scipy-tickets@scipy....
Tue Mar 1 21:34:08 CST 2011


#1398: problem with numpy 0's in stats.poisson.rvs
-------------------------+--------------------------------------------------
 Reporter:  parejkoj     |       Owner:  somebody
     Type:  defect       |      Status:  new     
 Priority:  normal       |   Milestone:          
Component:  scipy.stats  |     Version:  0.8.0   
 Keywords:               |  
-------------------------+--------------------------------------------------

Comment(by josefpktd):

 one more (and back to other things)

 the scipy.special functions don't work for the case of mu=0

 {{{
 >>> from scipy import special
 >>> special.pdtrik(0.5, 1e-16)
 0.0
 >>> special.pdtrik(0.5, 2)
 1.3234886842108262
 >>> special.pdtrik(0.5, 0)
 1e+100
 >>> special.pdtr(0.4, 0)
 nan
 >>> special.pdtrc(0.4, 0)
 nan
 }}}

 so ppf, sf, cdf, don't work and mu=0 would need to be treated as special
 case in these methods, unless scipy.special is extended to this case.

 So there are at least 2 bugs (which might also affect other distributions)
 and the question whether poisson should be extended to the degenerate case

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1398#comment:3>
SciPy <http://www.scipy.org>
SciPy is open-source software for mathematics, science, and engineering.


More information about the Scipy-tickets mailing list