Re: [Numpy-discussion] getting data pointer to numpy object in Pyrex

A Dimecres 29 Març 2006 00:28, Brian Blais va escriure:

...but I would like to do something like...

#------------------------------- def test2(d): # pass a python dict

 w=d['w']   # get the numpy object

 cdef double *w_p

 # get the pointers
 w_p=<double *>w.data

#-------------------------------

Is there a way to do this?

The next works for any numerical package that supports the array protocol:

data_address = int(w.__array_data__[0], 16) w_p = <double *>PyInt_AsLong(data_address)

and declare PyInt_AsLong as:

cdef extern from "Python.h": long PyInt_AsLong(object)

It is important to note that the above solution does not require to compile against the numpy (or any other numerical package) headers at all. See "A Pyrex Agnostic Class" recipe in the SciPy cookbook (http://www.scipy.org/Cookbook) for a more complete example.

Regards,