Graph partitioning using matrix values for preconditioning symmetric positive definite systems
For researchers solving large sparse linear systems in parallel, this work addresses the gap between partitioning for matrix-vector multiplication and preconditioning quality, offering a method that enhances solver convergence.
The paper proposes a spectral graph partitioning algorithm that uses matrix coefficient information to improve the quality of nonoverlapping additive Schwarz preconditioning for symmetric positive definite linear systems, achieving noticeable convergence improvements on test problems with large coefficient variations.
Prior to the parallel solution of a large linear system, it is required to perform a partitioning of its equations/unknowns. Standard partitioning algorithms are designed using the considerations of the efficiency of the parallel matrix-vector multiplication, and typically disregard the information on the coefficients of the matrix. This information, however, may have a significant impact on the quality of the preconditioning procedure used within the chosen iterative scheme. In the present paper, we suggest a spectral partitioning algorithm, which takes into account the information on the matrix coefficients and constructs partitions with respect to the objective of enhancing the quality of the nonoverlapping additive Schwarz (block Jacobi) preconditioning for symmetric positive definite linear systems. For a set of test problems with large variations in magnitudes of matrix coefficients, our numerical experiments demonstrate a noticeable improvement in the convergence of the resulting solution scheme when using the new partitioning approach.