A Parallel SSOR Preconditioner for Lattice QCD
  A parallelizable SSOR preconditioning scheme for Krylov subspace iterative solvers in lattice QCD applications involving Wilson fermions is presented. In actual Hybrid Monte Carlo and quark propagator calculations it helps to reduce the number of iterations by a factor of 2 compared to conventional odd-even preconditioning. This corresponds to a gain in cpu-time of 30\% - 70\% over odd-even preconditioning. 
S. Fischer, A. Frommer, U. Glaessner, S. Guesken, H. Hoeber, Th.   Lippert, G. Ritzenhoefer, K. Schilling, G. Siegert, A. Spitz