Control Formats for Unsymmetric and Symmetric Sparse Matrix–Vector Multiplications on OpenMP Implementations

• Published in: High Performance Computing for Computational Science - VECPAR 2012 pp. 236 - 248
• Main Authors: Katagiri, Takahiro, Sakurai, Takao, Igai, Mitsuyoshi, Ohshima, Satoshi, Kuroda, Hisayasu, Naono, Ken, Nakajima, Kengo
• Format: Book Chapter
• Language: English
• Published: Berlin, Heidelberg Springer Berlin Heidelberg
• Series: Lecture Notes in Computer Science
• Subjects: Branchless Segmented Scan; Control Formats; Sparse Matrix-Vector Multiplication (SpMV); Zero-element Computation-free
• ISBN: 3642387179; 9783642387173
• ISSN: 0302-9743; 1611-3349
• DOI: 10.1007/978-3-642-38718-0_24

In this paper, we propose “control formats” to obtain better thread performance of sparse matrix–vector multiplication (SpMV) for unsymmetric and symmetric matrices. By using the control formats, we established the following maximum speedups of SpMV in 16-thread execution on one node of the T2K Open Supercomputer: (1) 7.14( for an unsymmetric matrix by using the proposed Branchless Segmented Scan compared to the original Segmented Scan method; (2) 12.7( for a symmetric matrix by using the proposed Zero-element Computation-free method compared to a simple SpMV implementation.