[NumPy-Tickets] [NumPy] #1434: out argument ignored by var and std

NumPy Trac numpy-tickets@scipy....
Thu Mar 18 09:37:25 CDT 2010

#1434: out argument ignored by var and std
 Reporter:  a.naldi  |       Owner:  somebody
     Type:  defect   |      Status:  new     
 Priority:  high     |   Milestone:          
Component:  Other    |     Version:          
 Keywords:           |  
 when providing an axis, the mean, var and std functions return an array of
 results. The out argument enables to provide an already allocated array to
 store the result, which works fine for mean but not for var and std

 exemple ipython session:

 In [1]: import numpy as np
 In [2]: data = np.array(((1,2,3),(4,5,6),(7,8,9)))
 In [3]: result = np.zeros((3,))

 In [4]: data.mean(axis=1, out=result) == result
 Out[4]: array([ True,  True,  True], dtype=bool)

 In [5]: data.var(axis=1, out=result) == result
 Out[5]: array([False, False, False], dtype=bool)

 In [6]: data.var(axis=1, out=result)
 Out[6]: array([ 0.66666667,  0.66666667,  0.66666667])

 In [7]: result
 Out[7]: array([ 2.,  5.,  8.])


Ticket URL: <http://projects.scipy.org/numpy/ticket/1434>
NumPy <http://projects.scipy.org/numpy>
My example project

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