[Numpy-discussion] bug in numarray.maximum.reduce ?

Sebastian Haase haase at msg.ucsf.edu
Tue Jun 29 17:08:01 CDT 2004


Hi,

Is this a bug?:
>>> # (import numarray as na ; 'd' is a 3 dimensional array)
>>> d.type()
Float32
>>> d[80, 136, 122]
80.3997039795
>>> na.maximum.reduce(d[:,136, 122])
85.8426361084
>>> na.maximum.reduce(d) [136, 122]
37.3658103943
>>> 
>>> 
>>> na.maximum.reduce(d,0)[136, 122]
37.3658103943
>>> na.maximum.reduce(d,1)[136, 122]
Traceback (most recent call last):
  File "<input>", line 1, in ?
IndexError: Index out of range

I was using  na.maximum.reduce(d)  to get a "pixelwise" maximum along Z (axis 
0). But as seen above it does not get it right.  I then tried to reproduce 
this with some simple arrays, but here it works just fine:
>>> a = na.arange(4*4*4)
>>> a.shape=(4,4,4)
>>> na.maximum.reduce(a)
[[48 49 50 51]
 [52 53 54 55]
 [56 57 58 59]
 [60 61 62 63]]
>>> a = na.arange(4*4*4).astype(na.Float32)
>>> a.shape=(4,4,4)
>>> na.maximum.reduce(a)
[[ 48.  49.  50.  51.]
 [ 52.  53.  54.  55.]
 [ 56.  57.  58.  59.]
 [ 60.  61.  62.  63.]]
>>> 

Any hint ?

Regards,
Sebastian Haase




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