Third-order symplectic integration method with inverse time dispersion transform for long-term simulation

- We use the inverse time dispersion transform to the 3rd-order symplectic integration.
- It can greatly reduce the time-dispersion error, especially for long travel times.
- It is superior to the conventional 2nd- and high-order finite-difference methods.
- It allows the maximum temporal interval under stability conditions thus is efficient.
- We can obtain more accurate simulation results but with a lower computational cost.