text: 
  #ifndef CKDTREE_ORDERED_PAIR
  #define CKDTREE_ORDERED_PAIR
  
  struct ordered_pair {
      ckdtree_intp_t i;
      ckdtree_intp_t j;
  };
  
  inline void
  add_ordered_pair(std::vector<ordered_pair> *results,
                         const ckdtree_intp_t i, const intptr_t j)
  {
      if (i > j) {
          ordered_pair p = {j,i};
          results->push_back(p);
      }
      else {
          ordered_pair p = {i,j};
          results->push_back(p);;
      }
  }
  
  #endif
  
  
  