ODE Parameters

To obtain the trajectory, the above equation of motion in the form of ordinary differential equation is integrated in time. In the code, ODE integrator in GSL library[8] is used.

Currently the following stepper routines are available:

• ``rk2'' Embedded Runge-Kutta (2, 3) method.
• ``rk4'' 4th order (classical) Runge-Kutta.
• ``rkf45'' Embedded Runge-Kutta-Fehlberg (4, 5) method.
• ``rkck'' Embedded Runge-Kutta Cash-Karp (4, 5) method.
• ``rk8pd'' Embedded Runge-Kutta Prince-Dormand (8,9) method.
• ``rk2imp'' Implicit 2nd order Runge-Kutta at Gaussian points.
• ``rk4imp'' Implicit 4th order Runge-Kutta at Gaussian points.
• ``gear1'' M=1 implicit Gear method.
• ``gear2'' M=2 implicit Gear method.

Set the name in ``ode-solver'' at the initialization script. The variable ``ode-eps'' is the accuracy parameter $\epsilon$ for the GSL-ODE routine.