Parallel dichotomy algorithm for solving tridiagonal SLAEs

TL;DR: A parallel algorithm for solving tridiagonal systems of linear equations is proposed, utilizing a two-step approach with reduced communication interactions, and demonstrated to be efficient on both common- and distributed-memory supercomputers through theoretical estimates and computational experiments.

Abstract: A parallel algorithm for solving a series of matrix equations with a constant tridiagonal matrix and different right-hand sides is proposed and studied. The process of solving the problem is represented in two steps. The first preliminary step is fixing some rows of the inverse matrix of SLAEs. The second step consists in calculating solutions for all right-hand sides. For reducing the communication interactions, based on the formulated and proved main parallel sweep theorem, we propose an original algorithm for calculating share components of the solution vector. Theoretical estimates validating the efficiency of the approach for both the common- and distributed-memory supercomputers are obtained. Direct and iterative methods of solving a 2D Poisson equation, which include procedures of tridiagonal matrix inversion, are realized using the mpi technology. Results of computational experiments on a multicomputer demonstrate a high efficiency and scalability of the parallel sweep algorithm.