方向

我得說我沒有方向感，程式寫錯的問題是....我又把xy搞錯了...Orz，用手寫板畫了好幾張圖，終於搞懂方向，我不要再搞錯了...Orz

Matrix Multiplication Native Algorithm - divide and conquer

• Application Function
  

  void mulitplication(vector<vector<int> >& r, vector<vector<int> >& u,
      vector<vector<int> >& v){
      mult(make_pair(0,0), make_pair(0,0), make_pair(0,0), r.size(),
           r, u, v);
  }

• Recursive Function
  

  void mult(pair<int,int> lr, pair<int,int> lu, pair<int,int> lv,
            int size, vector<vector<int> >& r,
            vector<vector<int> >& u, vector<vector<int> >& v){
      
      static const int addr[8][2] = {{0,0}, {0,0}, {0,1}, {0,1},
                                     {1,0}, {1,0}, {1,1}, {1,1}};
      static const int addu[8][2] = {{0,0}, {0,1}, {0,0}, {0,1},
                                     {1,0}, {1,1}, {1,0}, {1,1}};
      static const int addv[8][2] = {{0,0}, {1,0}, {0,1}, {1,1},
                                     {0,0}, {1,0}, {0,1}, {1,1}};
  
      if(size>2){
          for(unsigned int i=0;i<8;i++){
              mult(make_pair(lr.first+((size >> 1)*addr[i][0]),
                               lr.second+((size >> 1)*addr[i][1])),
                   make_pair(lu.first+((size >> 1)*addu[i][0]),
                               lu.second+((size >> 1)*addu[i][1])),
                   make_pair(lv.first+((size >> 1)*addv[i][0]),
                               lv.second+((size >> 1)*addv[i][1])),
                   size/2,
                   r,
                   u,
                   v);
          }
      }
      else{   
          for(unsigned int i=0;i<8;i++){
              r[lr.first + addr[i][0]][lr.second + addr[i][1]] += 
                         u[lu.first + addu[i][0]][lu.second + addu[i][1]] * 
                         v[lv.first + addv[i][0]][lv.second + addv[i][1]];
          }
      }
  }

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因為方向搞錯而debug...Orz