docs: private void rowOpTransform2(Matrix M, int low, int high, double x, int k, double y, boolean notlast, double z, double r, double q)
      {
          double p;
          for (int j = low; j <= high; j++)
          {
              p = M.get(k, j) + q * M.get(k + 1,j);
              if (notlast)
              {
                  p = p + r * M.get(k + 2,j);
                  M.set(k + 2,j,  M.get(k+2, j) - p * z);
              }
              M.increment(k,   j, -p*x);
              M.increment(k+1, j, -p*y);
          }
      }