message: Add host synchronization in the Print of SpMat.
diff: @@ -580,6 +580,10 @@ public:
  inline std::ostream& operator<<(std::ostream& os, SparseMatrix const& mat)
  {
  + // HostRead forces synchronization
  + mat.HostReadI();
  + mat.HostReadJ();
  + mat.HostReadData();
  mat.Print(os);
  return os;
  }
  