Enhancement of Algebraic Block Multi-Color Ordering for ILU Preconditioning and Its Performance Evaluation in Preconditioned GMRES Solver

Abstract

Algebraic block multi-color ordering is known as a parallelization method for a sparse triangular solver. In the previous work, we confirmed the effectiveness of the method in a multi-threaded ICCG solver for a linear system with a symmetric coefficient matrix. In this study, we enhance the method so as to deal with an unsymmetric coefficient matrix. We develop a multi-threaded ILU-GMRES solver based on the enhanced method and evaluate its performance in terms of both the runtime and the number of iterations.