Total energy error as a function of time for a validation simulation consisting of a single star orbiting a system of 5 planets. The energy error of our method (in red) is compared to the results obtained using a 4th order Hermite code for all particles (green). The time evolution of the energy error is more erratic in the Nemesis method because of the close interactions of the orbiting star. The overall error, however, remains rather constant over a long timescale, whereas for the Hermite method the energy error is smoother but clearly grows with time.