On 23/03/09 15:40, Sturla Molden wrote:
> Jens Rantil wrote:
> > Hi all,
> >
> > So I have a C-function in a DLL loaded through ctypes. This particular
> > function returns a pointer to a double. In fact I know that this
> > pointer points to the first element in an array of, say for simplicity,
> > 200 elements.
> >
> > How do I convert this pointer to a NumPy array that uses this data (ie.
> > no copy of data in memory)? I am able to create a numpy array using a
> > copy of the data.
> >
>
> def fromaddress(address, nbytes, dtype=double):
>
> class Dummy(object): pass
>
> d = Dummy()
>
> d.__array_interface__ = {
>
> 'data' : (address, False),
>
> 'typestr' : numpy.uint8.str,
>
> 'descr' : numpy.uint8.descr,
>
> 'shape' : (nbytes,),
>
> 'strides' : None,
>
> 'version' : 3
>
> }
>
> return numpy.asarray(d).view( dtype=dtype )
>
Might I suggest that restype is going to be removed from the documentation,
it also cost me quite some time trying to get ndpointer to work with restype
when I first tried it until I finally came to the conclusion that an
approach like the above is necessary and ndpointer does not work with
restype.
Cheers
Jochen
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