code: private double determinant3x3(double t00, double t01, double t02,
                                    double t10, double t11, double t12,
                                    double t20, double t21, double t22) {
          return (t00 * (t11 * t22 - t12 * t21) +
                  t01 * (t12 * t20 - t10 * t22) +
                  t02 * (t10 * t21 - t11 * t20));
      }
docs: Calculate the determinant of a 3x3 matrix.
  @return result