Motion4D – A library for lightrays and timelike worldlines in the theory of relativity Original Research Article

The Motion4D-library solves the geodesic equation as well as the parallel- and Fermi–Walker-transport in four-dimensional Lorentzian spacetimes numerically. Initial conditions are given with respect to natural local tetrads which are adapted to the symmetries or the coordinates of the spacetime. Beside some already implemented metrics like the Schwarzschild and Kerr metric, the object oriented structure of the library permits to implement other metrics or integrators in a straight forward manner.