[Scipy-tickets] [SciPy] #1653: scoreatprecentile return wrong values when used on array with NaNs

SciPy Trac scipy-tickets@scipy....
Wed May 2 14:17:08 CDT 2012


#1653: scoreatprecentile return wrong values when used on array with NaNs
-------------------------+--------------------------------------------------
 Reporter:  imrisofer    |       Owner:  somebody   
     Type:  defect       |      Status:  new        
 Priority:  normal       |   Milestone:  Unscheduled
Component:  scipy.stats  |     Version:  0.10.0     
 Keywords:               |  
-------------------------+--------------------------------------------------
 the output of scoreatprecentile changed according to the number of
 Not-a-Numbers in the array

 {{{
 #create arrays
 #all of the arrays have the same precentiles
 a1 = array([1,2,3,4])
 a2 = array([1,2,3,4,nan])
 a3 = array([1,2,3,4,nan,nan])

 #put all arrays in one list
 l = [a1, a2, a3]

 #check precentiles of each array
 for i in range(3):
     print "array with %d NaNs" %(i)
     print "q25: ", scoreatpercentile(l[i], 25)
     print "q50: ", scoreatpercentile(l[i], 50)
     print "q75: ", scoreatpercentile(l[i], 75)
     print
 }}}

 output:

 {{{
 array with 0 NaNs
 q25:  1.75
 q50:  2.5
 q75:  3.25

 array with 1 NaNs
 q25:  2.0
 q50:  3.0
 q75:  4.0

 array with 2 NaNs
 q25:  2.25
 q50:  3.5
 q75:  nan

 }}}

-- 
Ticket URL: <http://projects.scipy.org/scipy/ticket/1653>
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