# SGT Theory-to-Practice Seminar

Eugene Velcharynski (Lawrence Berkeley National Lab)

Calvin Lab 116

## Graph Partitioning Using Matrix Entries for Preconditioning Symmetric Positive Definite Linear Systems.

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 this talk, we discuss a graph partitioning approach, which takes into account 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.