[NumPy-Tickets] [NumPy] #2033: a ** 2.0 has incorrect type

NumPy Trac numpy-tickets@scipy....
Mon Jan 30 09:54:41 CST 2012


#2033: a ** 2.0 has incorrect type
------------------------+---------------------------------------------------
 Reporter:  kasal       |       Owner:  somebody   
     Type:  defect      |      Status:  new        
 Priority:  normal      |   Milestone:  Unscheduled
Component:  numpy.core  |     Version:  1.6.0      
 Keywords:              |  
------------------------+---------------------------------------------------
 Hello,
 I observe an incorrect evaluation of the power operator for the exponent =
 2.0:
 {{{
 print 'NumPy:', np.__version__
 a = np.array([2, 4], dtype=np.int16)
 for e in np.arange(5.0):
     s = 'a**{}'.format(e)
     print '{:9} {}'.format(s, repr(eval(s)))

 !NumPy: 1.6.0
 a**0.0    array([ 1.,  1.])
 a**1.0    array([ 2.,  4.])
 a**2.0    array([ 4, 16], dtype=int16)
 a**3.0    array([  8.,  64.])
 a**4.0    array([  16.,  256.])
 }}}

 In all other cases, the output dtype is float, because of te float
 exponent.  But 'a**2.0' seems to be incorrectly reduced to 'a*a'.

-- 
Ticket URL: <http://projects.scipy.org/numpy/ticket/2033>
NumPy <http://projects.scipy.org/numpy>
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