[Numpy-discussion] strange bug

Alan G Isaac aisaac at american.edu
Tue Jun 20 00:18:16 CDT 2006


I think there is a bug in the **= operator,
for dtype=float.

Alan Isaac


## Script:
import numpy
print "numpy.__version__: ", numpy.__version__
''' Illustrate a strange bug:
'''
y = numpy.arange(10,dtype=float)
print "y: ",y
y *= y
print "y**2: ",y
z = numpy.arange(10,dtype=float)
print "z: ", z
z **= 2
print "z**2: ", z

## Output:
numpy.__version__:  0.9.8
y:  [ 0.  1.  2.  3.  4.  5.  6.  7.  8.  9.]
y**2:  [  0.   1.   4.   9.  16.  25.  36.  49.  64.  81.]
z:  [ 0.  1.  2.  3.  4.  5.  6.  7.  8.  9.]
z**2:  [  0.00000000e+00   1.00000000e+00   1.60000000e+01   8.10000000e+01
   2.56000000e+02   6.25000000e+02   1.29600000e+03   2.40100000e+03
   4.09600000e+03   6.56100000e+03]





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