[Numpy-tickets] [NumPy] #236: reduceat cornercase

NumPy numpy-tickets at scipy.net
Mon Aug 7 23:56:41 CDT 2006


#236: reduceat cornercase
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 Reporter:  martin_wiechert  |        Owner:  somebody   
     Type:  enhancement      |       Status:  new        
 Priority:  normal           |    Milestone:  1.0 Release
Component:  numpy.core       |      Version:  devel      
 Severity:  normal           |   Resolution:             
 Keywords:                   |  
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Changes (by oliphant):

  * type:  defect => enhancement

Comment:

 Unfortunately, perhaps, the reduceat method of NumPy follows the behavior
 of the  reduceat method of Numeric for this corner case.

 There is no facility for returning the "identity" element of the operation
 in cases of index-equality.  The defined behavior is to return the element
 given by the first index if the slice returns an empty sequence.
 Therefore, the documented and actual behavior of reduceat in this case is
 to construct

 [a[1], add.reduce(a[1:])]

 This is a feature request.

-- 
Ticket URL: <http://projects.scipy.org/scipy/numpy/ticket/236>
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