A parallel iterative solver for positive-definite systems with hybrid MPI-OpenMP parallelization for multi-core clusters

This article is devoted to the development and study of an algorithm for solving large systems of linear algebraic equations with sparse stiffness matrix on supercomputer by using the preconditioned conjugate gradient method (PCG). An efficient preconditioner is constructed on the basis of the domain decomposition method (the additive Schwarz method) which makes it possible to implement the algorithm on several computing nodes. We describe the parallel algorithm of the action of the stiffness matrix and the preconditioner on a vector. In addition, to increase the computational efficiency we make use of the routines from Intel (R) MKL: the direct solver (PARDISO) and the matrix-vector multiplication for sparse matrices (Sparse BLAS). We also study efficiency of using OpenMP directives on each computational node and compare it with pure MPI parallelization. The corresponding performance and scalability charts are presented. (C) 2012 Elsevier B.V. All rights reserved.