Re: [Boost-users] [boost.python] use of multi_array in python

From: Daniel Wallin (dalwan01_at_[hidden])
Date: 2006-07-03 16:04:02

Sebastien Fortier wrote:
> Thank you very much Daniel!
> 
> I had another question, is it possible to use multi_array and 
> const_multi_array_ref together in python.
> What I mean is, if I create a multi_array from python through my c++ 
> functions and I want to pass this array to another c++ function that 
> uses a const_multi_array_ref how do I manage this in the interface file? 
> is this possible?
> 
> I added class_<const_multi_array_ref<double, 2> 
>  >("const_multi_array_2d_ref"); to my interface file but the types seem 
> to be incompatible.

You need to let Boost.Python know that the types are convertible:

  implicitly_convertible<
      multi_array<double, 2>
    , multi_array_ref<double, 2>
  >();

  implicitly_convertible<
      multi_array<double, 2>
    , const_multi_array_ref<double, 2>
  >();

Should do it. See http://www.boost.org/libs/python/doc/v2/implicit.html.

> I would prefer to use the const_multi_array_ref with the multi_arrays to 
> avoid copies...

If you already have multi_array's, why don't you just pass them by
reference?

-- 
Daniel Wallin