Hybrid parallel linear system solvers

This paper presents a new approach to the solution of nonsymmetric linear s ystems that uses hybrid techniques based on both direct and iterative metho ds. An implicitly preconditioned modified system is obtained by applying pr ojections onto block rows of the original system, Our technique provides th e flexibility of using either direct or iterative methods for the solution of the preconditioned system. The resulting algorithms are robust, and can be implemented with high efficiency on a variety of parallel architectures. The algorithms are used to solve linear systems arising from the discretiz ation of convection-diffusion equations as well as those systems that arise from the simulation of particulate flows. Experiments are presented to ill ustrate the robustness and parallel efficiency of these methods.