QVM: Quaternions, Vectors, Matrices

vec_index_write

#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 );
    }
}

Returns:

A mutable reference to the i-th element of a.

Preconditions:

i >= 0 && i < vec_traits<A>::dim.

Note:

This function uses template metaprogramming and can be used even if the optional access function vec_traits<A>::write_element_idx is not available.

See also: boost/qvm/vec_index.hpp