Boost LA

#include <boost/la/matrix_mul_scalar.hpp> 
#include <boost/la/matrix_div_scalar.hpp> 
#include <boost/la/matrix_mul_eq_scalar.hpp> 
#include <boost/la/matrix_div_eq_scalar.hpp>

namespace
boost
    {
    namespace
    la
        {
        //*** Binary matrix,scalar operations ***
        
        //Only enabled if: is_matrix<A>::value
        template <class A>
        typename deduce_matrix<A>::type
        operator*( A const & a, matrix_traits<A>::scalar_type s );        
        
        //Only enabled if: is_matrix<A>::value
        template <class A>
        typename deduce_matrix<A>::type
        operator/( A const & a, matrix_traits<A>::scalar_type s );        
        
        //Only enabled if: is_matrix<A>::value
        template <class A>
        A &
        operator*=( A & a, matrix_traits<A>::scalar_type s );        
        
        //Only enabled if: is_matrix<A>::value
        template <class A>
        A &
        operator/=( A & a, matrix_traits<A>::scalar_type s );
        }
    }