Abstract
A strategy to harness fine-grained parallelism for linear solvers within computational tools that operate on distributed domains is presented. “MPI + X” is the industry term for multilevel parallelism. “MPI” refers to the component coordinating inter-node communication via message passing. Within this article we focus our attention on the “X”, the on-node component that utilizes fine-grained parallelism in shared memory. In this work, “X” is OpenMP® on Intel® Xeon® Phi™ Knight’s Landing and Intel® Xeon® Skylake processors, and “X” is CUDA® 9 on a NVIDIA® Tesla® P100 GPU accelerator. The strategy is applied to the right preconditioned GMRES method to explore two pairs of algorithmic alternatives, 1) preconditioner generation by Gaussian Elimination or PariLU algorithms, and 2) orthonormalization of a Krylov subspace by the commonly used modified Gram-Schmidt Arnoldi or the Householder Transformation Arnoldi processes. Particular emphasis is placed on the implications of parallelism on numerical qualities of the solution process. Preconditioning GMRES with factorizations generated by the PariLU algorithm is found to effectively accelerate convergence for some poorly conditioned linear systems. Orthonormalizing a GMRES Krylov subspace with the Householder Transformation Arnoldi processes is found to match or surpass the convergence rate achieved utilizing the modified Gram-Schmidt Arnoldi process when searching for approximate solutions to 10 linear systems from modern computational engineering applications.
Original language | English |
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Title of host publication | AIAA Information Systems-AIAA Infotech at Aerospace |
Publisher | American Institute of Aeronautics and Astronautics Inc, AIAA |
ISBN (Print) | 9781624105272 |
DOIs | |
State | Published - Jan 1 2018 |
Externally published | Yes |
Event | AIAA Information Systems-AIAA Infotech at Aerospace, 2018 - Kissimmee, United States Duration: Jan 8 2018 → Jan 12 2018 |
Publication series
Name | AIAA Information Systems-AIAA Infotech at Aerospace, 2018 |
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Conference
Conference | AIAA Information Systems-AIAA Infotech at Aerospace, 2018 |
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Country/Territory | United States |
City | Kissimmee |
Period | 01/8/18 → 01/12/18 |
Funding
The Co-design Approach for Advances in Software and Hardware (CoDAASH) project focuses on understanding the relationship between algorithms and hardware platforms and how to jointly optimize the software and hardware in order to achieve efficient implementations for applications in materials science, chemistry, and physics. CoDAASH is a joint effort between the University of Tennessee, Knoxville; Iowa State University; University of Texas, El Paso; and the University of California, San Diego; and is funded by the United States Air Force Office of Scientific Research (AFOSR). This material is based upon work supported by the AFOSR under Award No. FA9550-12-1-0476.