#include <boost/qvm/vec_index.hpp>
namespace boost
{
namespace qvm
{
//Only enabled if:
// is_vec<A>::value
template <class A>
typename vec_traits<A>::scalar_type &
vec_index_write( A & a, int i );
}
}
A mutable reference to the i-th element of a.
i >= 0 && i < vec_traits<A>::dim.
This function uses template metaprogramming and can be used even if the optional access function vec_traits<A>::write_element_idx is not available.