A block-tridiagonal solver with two-level parallelization for finite element-spectral codes
Name
A block-tridiagonal.pdf
Size
6.61 MB
Format
Adobe PDF
Checksum (MD5)
1d25470c916e1779eb76e886a12d071b
Author(s)
Lee, Jungpyo
Wright, John C
Date Issued
June 2014
Journal
Computer Physics Communications
Publisher
Elsevier
Citation
Lee, Jungpyo and Wright, John C. “A Block-Tridiagonal Solver with Two-Level Parallelization for Finite Element-Spectral Codes.” Computer Physics Communications 185, 10 (October 2014): 2598–2608 © 2014 Elsevier B.V.
Version
Author's final manuscript
Abstract
Two-level parallelization is introduced to solve a massive block-tridiagonal matrix system. One-level is used for distributing blocks whose size is as large as the number of block rows due to the spectral basis, and the other level is used for parallelizing in the block row dimension. The purpose of the added parallelization dimension is to retard the saturation of the scaling due to communication overhead and inefficiencies in the single-level parallelization only distributing blocks. As a technique for parallelizing the tridiagonal matrix, the combined method of "Partitioned Thomas method" and "Cyclic Odd-Even Reduction" is implemented in an MPI-Fortran90 based finite element-spectral code (TORIC) that calculates the propagation of electromagnetic waves in a tokamak. The two-level parallel solver using thousands of processors shows more than 5 times improved computation speed with the optimized processor grid compared to the single-level parallel solver under the same conditions. Three-dimensional RF field reconstructions in a tokamak are shown as examples of the physics simulations that have been enabled by this algorithmic advance.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Terms of Use
Creative Commons Attribution-NonCommercial-NoDerivs License
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1016/j.cpc.2014.06.006
