Institute of Computational Science, Swiss Federal Institute of Technology, Zurich, Switzerland. schneadr@inf.ethz.ch <schneadr@inf.ethz.ch>|Institute of Computational Science, Swiss Federal Institute of Technology, Zurich, Switzerland. schneadr@inf.ethz.ch <schneadr@inf.ethz.ch>|Institute of Computational Science, Swiss Federal Institute of Technology, Zurich, Switzerland. schneadr@inf.ethz.ch <schneadr@inf.ethz.ch>