  Modern synchrotron light sources are often characterized with high-brightness
synchrotron radiation from insertion devices. Inevitably, insertion devices
introduce nonlinear distortion to the beam motion. Symplectic tracking is
crucial to study the impact, especially for the low- and medium-energy storage
rings. This paper uses a Robinson wiggler as an example to illustrate an
universally applicable analytical representation of the magnetic field and to
summarizes four different symplectic tracking methods.
