#include <boost/qvm/mat_operations.hpp>
namespace boost
{
    namespace qvm
    {
        template <class T,int D>
        -unspecified-return-type- zero_mat();
        
        template <class T,int R,int C>
        -unspecified-return-type- zero_mat();
    }
}
A read-only matrix of unspecified type with scalar_type T, R rows and C columns (or D rows and D columns), with all elements equal to scalar_traits<T>::value(0).