Re: [boost] multi_array, how to get dim?

From: Kevin Spinar (spinarkm_at_[hidden])
Date: 2006-09-21 15:50:30

On 9/21/06, Neal Becker <ndbecker2_at_[hidden]> wrote:
> Maybe I'm missing something obvious.  How do I get a compile-time constant
> for the numDim from a multi_array?
>
> For example:
>
> template<typename matrix_t>
> void F (matrix_t const& m) {
>   typedef typename matrix_t::value_type value_type;
>   const int dim = ???

Maybe I'm missing something too, but I couldn't find member for that.
Is there some reason you aren't doing:

template<typename T, int Dims>
void F(boost::multi_array<T, Dims>& m) {
  typedef T value_type;
  const int dim = Dims;
}

Alternatively, you could use this class:

template<typename Matrix>
struct get_dims {};

// partial template specialization
template<typename T, int Dims>
struct get_dims<boost::multi_array<T, Dims> > {
   const int dims = Dims;
};

template<typename matrix_t>
void F (matrix_t const& m) {
  typedef typename matrix_t::value_type value_type;
  const int dim = get_dims<matrix_t>::dims;
// ...

Which perhaps is a little more flexible.

Kevin Spinar