Astrophysical particle simulations with large custom GPU clusters on three continents. - Rainer Spurzem; Peter Berczik; Ingo Berentzen; Keigo Nitadori; Tsuyoshi Hamada; Guillermo Marcus Martinez; Andreas Kugel; Reinhard Männer; J. Fiestas; Robi Banerjee; Ralf Klessen (Comput. Sci. Res. Dev., 2011)