Solved by hemeng in post #2 
              
              
                OH MY GOSH!!! I solve it. 
The problem is still my inexperience. 
The definition of wmma::fragment is 
  // 
  // Fragment template
  // 
  template<typename Use, int m, int n, int k, typename T, typename Layout=void> class fragment;

  // 
  // Fragments for 16x16x16
  // 
  template<> class fragme…