Re: [Boost-users] [multi_array] Access a view's index_range

Subject: Re: [Boost-users] [multi_array] Access a view's index_range
From: Ronald Garcia (garcia_at_[hidden])
Date: 2008-10-09 19:55:43

Hi Robert,

The index_range object is used to create views, but it doesn't stay  
around.  However, all of the information from an index_range is still  
accessible.  You want to look into the following 3 MultiArray concept  
functions: indices(), strides(), and shape().

Based on your code,  it looks like you're trying to get the valid  
indices for the array so you can dereference it.

If you're not changing the index base (meaning your array indices  
always start at 0), then you want to write:

typedef Grid::array_view<2>::type view_t

...

for(view_t::index i = 0; i != view.size(); ++i) { ... }

HTH,
ron

On Oct 9, 2008, at 5:40 AM, Robert Jones wrote:

> How do I access the index_range of an array_view? ie.,
>
> typedef boost::multi_array<Cell,2 > Grid;
> Grid grid( boost::extents[9][9]);
> Grid::array_view<2> view = grid[indices[range(), range()]];
>
> for (Grid::index i = view.?????.start(); i != view.?????.finish(); + 
> +i)
> {....}
>
> where I'm expecting i to take values 0..8 inclusive.