#include <boost/qvm/mat_index.hpp>
namespace boost
{
namespace qvm
{
//Only enabled if:
// is_mat<A>::value
template <class A>
typename mat_traits<A>::scalar_type &
mat_index_write( A & a, int r, int c );
}
}
A mutable reference to the element of a at row r and column c.
r >= 0 && r < mat_traits<A>::rows && c >= 0 && c < mat_traits<A>::cols.
This function uses template metaprogramming and can be used even if the optional access function mat_traits<A>::write_element_idx is not available.