[Numpy-discussion] Latest Array-Interface PEP
oliphant at ee.byu.edu
Thu Jan 4 16:49:32 EST 2007
Christopher Barker wrote:
> First, thanks for doing this -- Python really needs it!
> > While this approach
>> works, it requires attribute lookups which can be expensive when
>> sharing many small arrays.
> Ah, I do like reducing that overhead -- I know I use arrays a lot for
> small data sets too, so that overhead can be significant.
> I'm not well qualified to review the tech details, but to make sure I
> have this right:
>> static PyObject* bf_getarrayview (PyObject *obj)
>> This function must return a new reference to a PyArrViewObject
>> which contains the details of the array information exposed by the
>> object. If failure occurs, then NULL is returned and an exception
> So If I have some C code that wants to use any array passed in, I can
> just call:
> bf_getarrayview (obj)
Yes you could call this (but you would call it from the type object like
Or more likely (and I should add this to the C-API) you would call.
which does this under the covers.
> and if it doesn't return NULL, I have a valid array that I can query to
> see if it fits what I'm expecting.
> Have I got that right?
> If so, this would be great.
> By the way,, how compatible is this with the existing buffer protocol?
It's basically orthogonal. In other-words, if you defined the array
view protocol you would not need the buffer protocol at all. But you
could easily define both.
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