# include <cassert>
# include <mat2cpp.hpp>
namespace mat2cpp {
     matrix<double> diag_prod 
     (const matrix<double> &x, const matrix<double> &y)
     {    size_t i, j, m(y.size1()), n(y.size2());
          matrix<double> z(m, n);
          if( x.size1() == 1 )
          {    // check that dimensions match
               assert( x.size2() == m );
               for(i = 0; i < m; i++)
               {    for(j = 0; j < n; j++)
                         z(i, j) = x(0, i) * y(i, j);
               }
          }
          else if( x.size2() == 1 )
          {    // check that dimensions match
               assert( x.size1() == m );
               for(i = 0; i < m; i++)
               {    for(j = 0; j < n; j++)
                         z(i, j) = x(i, 0) * y(i, j);
               }
          }
          else
          {    // this is a diag_prod usage error
               assert(0);
          }
          return z;
     }
}