[Numpy-discussion] np.array execution path

Sebastian Berg sebastian@sipsolutions....
Sat Sep 22 13:01:21 CDT 2012


Hi,

I have a bit of trouble figuring this out. I would have expected
np.asarray(array) to go through ctors, PyArray_NewFromArray, but it
seems to me it does not, so which execution path is exactly taken here?
The reason I am asking is that I want to figure out this behavior/bug,
and I really am not sure which function is responsible:

In [69]: o = np.ones(3)

In [70]: no = np.asarray(o, order='C')

In [71]: no[:] = 10

In [72]: o # OK, o was changed in place:
Out[72]: array([ 10.,  10.,  10.])

In [73]: no.flags # But no claims to own its data!
Out[73]: 
  C_CONTIGUOUS : True
  F_CONTIGUOUS : True
  OWNDATA : True
  WRITEABLE : True
  ALIGNED : True
  UPDATEIFCOPY : False

In [74]: no = np.asarray(o, order='F')

In [75]: no[:] = 11

In [76]: o # Here asarray actually returned a real copy!
Out[76]: array([ 10.,  10.,  10.])


Thanks,

Sebastian




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