[Numpy-discussion] casting

[Neal Becker]

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.