Highly Optimized Code for Lattice Quantum Chromodynamics on the CRAY T3E

In lattice quantum chromodynamics, large systems of linear equations have to be solved to compute physical quantities. The availability of efficient parallel Krylov subspace solvers plays a vital role in the solution of these systems. We present a detailed analysis of the performance of the stabilised biconjugate gradient (BiCGStab) algorithm with symmetric successive over-relaxed (SSOR) preconditioning on a massively parallel CRAY T3E system. 1. Lattice Gauge Theory Computations The numerical investigation of quantum chromodynamics (QCD) on a four-dimensional space-time grid is one of the grand challenges in high-performance scientific computing [1]. QCD is generally considered to be the fundamental theory which describes the strong forces binding quarks with gluons to form the known hadrons like the proton or neutron [2]. Even after 20 years of research, QCD still has not been solved in a nonperturbative analytical approach, and it is by now widely believed that the controlled numerical treatment of the theory on the lattice on very fast parallel supercomputers i