[Numpy-discussion] access ndarray in C++

Hoyt Koepke hoytak@gmail....
Wed Apr 23 14:51:33 CDT 2008


Just to add something from personal experience in case it's useful...

I write a lot of code that works on numpy arrays that goes between
python and c++ (too used to OO to stick with pure c). I've been using
scipy.weave to interface to blitz++ arrays in my c++ code.  The
blitz++ library has been wonderful in my experience -- it supports
arrays up to 11 dimensions, slicing, etc.  -- essentially a very
useful subset of numpy's operations.  It's also nice because it can
interface without copying any data; it just provides a wrapper class
that sits on a numpy array.  The library is included as part of scipy.

I recently wrote a function that automatically generates wrappers for
a c++ function that accepts blitz++ arrays which I recently posted to
the scipy list.  You just specify function names and the list of
argument types (nparrays included) and it generates the wrapper code.
Quite easy.  It's pertinent to the discussion here, so I'll send it
again.  Included is a full working example with setup.py.  let me know
if it helps/is confusing/doesn't work/etc.

--Hoyt





On Wed, Apr 23, 2008 at 12:30 PM, Andreas Klöckner
<lists@informa.tiker.net> wrote:
> On Mittwoch 23 April 2008, Christopher Barker wrote:
>  > NOTE:
>  > Most folks now think that the pain of writing extensions completely by
>  > hand is not worth it -- it's just too easy to make reference counting
>  > mistakes, etc. Most folks are now using one of:
>  >
>  > Cython (or Pyrex)
>  > SWIG
>  > ctypes
>
>  IMO, all of these deal better with C than they do with C++. There is also a
>  number of more C++-affine solutions:
>
>  - Boost Python [1]. Especially if you want usable C++ integration. (ie. more
>  than basic templates, etc.)
>
>  - sip [2]. Used for PyQt.
>
>  Andreas
>
>  [1] http://www.boost.org/doc/libs/1_35_0/libs/python/doc/index.html
>  [2] http://www.riverbankcomputing.co.uk/sip/index.php
>
> _______________________________________________
>  Numpy-discussion mailing list
>  Numpy-discussion@scipy.org
>  http://projects.scipy.org/mailman/listinfo/numpy-discussion
>
>



-- 
+++++++++++++++++++++++++++++++++++
Hoyt Koepke
UBC Department of Computer Science
http://www.cs.ubc.ca/~hoytak/
hoytak@gmail.com
+++++++++++++++++++++++++++++++++++
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