New subject: numarray.sum should raise exception for wrong axis argument - and slicing ...

23 Jun 2004


      Hi,
please take a look at this:
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na.sum( na.zeros((2,6)) )
[0 0 0 0 0 0]
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na.sum( na.zeros((2,6)) , 0)
[0 0 0 0 0 0]
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na.sum( na.zeros((2,6)) , 1)
[0 0]
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na.sum( na.zeros((2,6)) , 2)
[0 0]
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na.sum( na.zeros((2,6)) , 3)
[0 0]
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na.sum( na.zeros((2,6)) , 4)
[0 0]
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na.sum( na.zeros((2,6)) , -1)
[0 0]
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na.sum( na.zeros((2,6)) , -2)
[0 0 0 0 0 0]
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na.sum( na.zeros((2,6)) , -3)
[0 0]
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na.sum( na.zeros((2,6)) , -4)
[0 0]
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I think here should be a ValueError exception thrown rather than defaulting to 
the '-1'-axis.  Comments ?
Also this applies to (all?) other functions that have an 'axis' argument.
And further I just found that putting "too many slicings" to an array also 
gets silently ignored:
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b.shape
(7, 128, 128, 128)
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b[2,2,2,2,3]
Traceback (most recent call last):
  File "<input>", line 1, in ?
IndexError: too many indices.
BUT:
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b[2:3 , 2:3 , 2:3 , 2:3 , 2:3 , 2:3]
[[[[ 0.]]]]
I find this very confusing !! Is there any good reason not to have the 
"IndexError" exception in all cases ?
Thanks,
Sebastian Haase

numarray.sum should raise exception for wrong axis argument - and slicing ...

Sebastian Haase

Todd Miller

Sebastian Haase

Todd Miller

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