[pypy-dev] numpypy buffer interface for slices different from numpy

[Kay F. Jahnke]

Hi group!

I stumbled upon a difference in numpypy's ndarray buffer interface. If I 
take the address of the data of a slice in numpy, I get a pointer to the 
first element in the slice. In numpypy I get a pointer to the data I 
took the slice from. I wonder if this is a bug or deliberate? If it's a 
bug, it's probably merely an omission of adding the offset to the data 
pointer. Here's what I observed:

$ pypy
Python 2.7.3 (aa7b56060ddd, Apr 22 2013, 22:03:12)
[PyPy 2.0.0-beta2 with GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
And now for something completely different: ``PyPy 1.2 released -
http://pypy.org/''
 >>>> import numpypy as np
 >>>> a=np.zeros(10)
 >>>> a.__array_interface__['data'][0]
-1220095968
 >>>> a[2:].__array_interface__['data'][0]
-1220095968                                 <<<<<<<< same value

$ python
Python 2.7.3 (default, Apr 10 2013, 05:46:21)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> import numpy as np
 >>> a=np.zeros(10)
 >>> a.__array_interface__['data'][0]
162282152
 >>> a[2:].__array_interface__['data'][0]
162282168                                  <<<<<<<<<<< different value

with regards
Kay F. Jahnke