[Numpy-discussion] casting

Neal Becker ndbecker2@gmail....
Thu Jan 17 15:23:41 CST 2008


Charles R Harris wrote:

> On Jan 16, 2008 11:30 AM, Neal Becker <ndbecker2@gmail.com> wrote:
> 
>> Hans Meine wrote:
>>
>> > Am Montag, 14. Januar 2008 19:59:15 schrieb Neal Becker:
>> >> I don't want to use FROM_O here, because I really can only handle
>> certain
>> >> types.  If I used FROM_O, then after calling FROM_O, if the type was
>> not
>> >> one I could handle, I'd have to call FromAny and convert it.
>> > What is the problem with that?  Is there any, apart from the code not
>> > being as elegant as one might want it to be?
>> >
>> > AFAICS, it would be nice to have a function that takes a PyObject and a
>> > list
>> > of supported types and would perform the minimal needed conversion.
>>  OTOH,
>> > if your code is templatized, it is maybe already written in an
>> > STL-style way,
>> > using iterators?  Then, it would be very simple to provide a set of
>> > iterators that e.g. promote unsigned short->int such that your
>> > algorithm can work on the original data without creating a copy.
>> >
>> > Note that internally, ufuncs already do what you want.  I have not yet
>> > found the perfect way for a NumPy/C++ integration (which I am
>> > interested in, possibly using boost::python which I have been doing for
>> > the last years), but for element-wise operators, it would be very cool
>> > to be able to re-use the ufunc mechanism (i.e. only implement the inner
>> > loop, not caring about non-contiguous arrays etc.).
>> >
>>
>> I have been making some good progress on numpy/c++ integration.  I can
>> share
>> some examples if there is interest.
>>
> 
> I would be interested in that.
> 
> Chuck
I placed a little test code and a quick design doc here:
https://nbecker.dyndns.org/numpy.ext.tar.bz2



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