[Boost-users] best of both worlds: ptr_vector and multi_array

From: Levent Yilmaz (sly5+gmane_at_[hidden])
Date: 2006-09-14 14:27:52

This question is perhaps, rather a feature request from multi_array:

ptr_vector (of pointer container library) is nice but it is not multi 
dimensional, multi_array is nice but it is not, well, ptr_multi_array.

For any single dimensional random access array there is multi_array_ref:

/**/
boost::array<size_t,2> shape = {4,4};
std::vector<int> v(16);
boost::multi_array_ref<int,2> mav(&v[0],shape);
/**/

But, this (&v[0]) wouldn't work with ptr_vector, due to the indirected 
interface of pointer containers. I was thinking, one way of achieving 
this is to have multi_array_ref work with any random access container, 
rather than just plain C array. The above example would be:

/**/
boost::array<size_t,2> shape = {4,4};
std::vector<int> v(16);
boost::multi_array_ref< std::vector<int>, 2 > mav(v,shape);
/**/

Note the change of the first template parameter of multi_array_ref from 
the element type to, container type. This way, it would similarly be 
possible to use it with ptr_vector, or any other random access container 
for that matter:

/**/
class foo;
boost::array<size_t,2> shape = {4,4};
boost::ptr_vector<foo> v(16);
boost::multi_array_ref< boost::ptr_vector<foo>, 2 > mav(v,shape);
/**/

The thing is, I am not sure if this can be done with the multi_array 
library.

Or, what other ways are there to get a multi dimenstional pointer container?

thanks
- Levent.