A GPU-Accelerated Parallel Preconditioner for the Solution of the Boltzmann Transport Equation for Semiconductors

The solution of large systems of linear equations is typically achieved by iterative methods. The rate of convergence of these methods can be substantially improved by the use of preconditioners, which can be either applied in a black-box fashion to the linear system, or exploit properties specific to the underlying problem for maximum efficiency. However, with the shift towards multiand many-core computing architectures, the design of sufficiently parallel preconditioners is increasingly challenging. This work presents a parallel preconditioning scheme for a state-of-theart semiconductor device simulator and allows for the acceleration of the iterative solution process of the resulting system of linear equations. The method is based on physical properties of the underlying system of partial differential equations and results in a block preconditioner scheme, where each block can be computed in parallel by established serial preconditioners. The efficiency of the proposed scheme is confirmed by numerical experiments using a serial incomplete LU factorization preconditioner, which is accelerated by one order of magnitude on both multi-core central processing units and graphics processing units with the proposed scheme.