Boost LA

#include <boost/la/matrix_access.hpp>

namespace
boost
    {
    namespace
    la
        {
        //*** Accessing matrix elements ***
        
        template <int R,int C>
        -unspecified-return-type- A();
        
        -unspecified-return-type- A00();
        -unspecified-return-type- A01();
        ...
        -unspecified-return-type- A09();
        -unspecified-return-type- A10();
        ...
        ...
        -unspecified-return-type- A99();
        }
    }