El ds 13 de 01 del 2007 a les 14:42 +0900, en/na David Cournapeau va
escriure:
> > No, only if it's contiguous (I'm not sure about alignment)
> According to numpy ebook, you need alignement for deferencing
> pointers. But I guess non aligned arrays are not really common.
Unaligned arrays can be quite common if you use recarrays often:
In [18]:a=numpy.empty(3, dtype="S1,i4,f8")
In [19]:a.dtype.fields.items()
Out[19]:
[('f0', (dtype('|S1'), 0)),
('f1', (dtype('int32'), 1)),
('f2', (dtype('float64'), 5))]
In [20]:f1=a['f1']
In [21]:f1.flags
Out[21]:
C_CONTIGUOUS : False
F_CONTIGUOUS : False
OWNDATA : False
WRITEABLE : True
ALIGNED : False
UPDATEIFCOPY : False
And dereferencing unaligned pointers do cause a crash in general, but
not in all architectures (i386 being one of them).
Cheers,
--
Francesc Altet | Be careful about using the following code --
Carabos Coop. V. | I've only proven that it works,
www.carabos.com | I haven't tested it. -- Donald Knuth
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