code: protected static void sortBound (double[] bound, int bc) {
          for (int i = 0; i < bc - 4; i += 4) {
              int k = i;
              for (int j = i + 4; j < bc; j += 4) {
                  if (bound[k] > bound[j]) {
                      k = j;
                  }
              }
              if (k != i) {
                  double tmp = bound[i];
                  bound[i] = bound[k];
                  bound[k] = tmp;
                  tmp = bound[i + 1];
                  bound[i + 1] = bound[k + 1];
                  bound[k + 1] = tmp;
                  tmp = bound[i + 2];
                  bound[i + 2] = bound[k + 2];
                  bound[k + 2] = tmp;
                  tmp = bound[i + 3];
                  bound[i + 3] = bound[k + 3];
                  bound[k + 3] = tmp;
              }
          }
      }
docs: Sorts a bound array.