[Numpy-discussion] @Dag re numpy.pxd

mark florisson markflorisson88@gmail....
Sat Feb 11 15:27:44 CST 2012

On 11 February 2012 20:31, Charles R Harris <charlesr.harris@gmail.com> wrote:
> Hi Dag,
> This probably needs to be on the cython mailing list at some point, but I
> thought I'd start the discussion here. Numpy is going to begin deprecating
> direct access to ndarray/dtype internals, ala arr->data etc. There are
> currently macros/functions for many of these operations in the numpy
> development branch and I expect more to go in over the coming year. Also,
> some of the macros have been renamed. I don't know the best way for Cython
> to support this, but the current version (0.15 here) generates code that
> will fail if the deprecated things are excluded. Ideally, numpy.pxd would
> have numpy version dependent parts but I don't know if that is possible. In
> any case, I'd like your thoughts on the best way to coordinate this
> migration with Cython.
> Chuck
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This was discussed not too long ago on the cython-devel mailing list:

I personally think it'd be nice to not break existing Cython code, by
e.g. writing nogil cdef properties (something which doesn't currently
exist). That way the properties could use the non-deprecated way to
actually access the data from numpy. (In any case the deprecated numpy
functionality should go through a deprecation process before being

Alternatively, as Dag mentioned in the cython-devel thread, we could
just deprecate the fields in Cython as well and place the burden on
the user (and possibly issue warnings for their use).

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