Solving Systems of Linear Equations on the CELL Processor Using Cholesky Factorization

Kurzak, Jakub and Buttari, Alfredo and Dongarra, Jack (2007) Solving Systems of Linear Equations on the CELL Processor Using Cholesky Factorization. [MIMS Preprint]

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Abstract

The STI CELL processor introduces pioneering solutions in processor architecture. At the same time it presents new challenges for the development of numerical algorithms. One is effective exploitation of the differential between the speed of single and double precision arithmetic; the other is efficient parallelization between the short vector SIMD cores. In this work, the first challenge is addressed by utilizing a mixed-precision algorithm for the solution of a dense symmetric positive definite system of linear equations, which delivers double precision accuracy, while performing the bulk of the work in single precision. The second challenge is approached by introducing much finer granularity of parallelization than has been used for other architectures and using a lightweight decentralized synchronization. The implementation of the computationally intensive sections gets within 90 percent of peak floating point performance, while the implementation of the memory intensive sections reaches within 90 percent of peak memory bandwidth. On a single CELL processor, the algorithm achieves over 170 Gflop/s when solving a symmetric positive definite system of linear equation in single precision and over 150 Gflop/s when delivering the result in double precision accuracy.

Item Type: MIMS Preprint
Additional Information: Appears also as Technical Report UT-CS-07-596, Department of Computer Science, University of Tennessee, Knoxville, TN, USA, May 2007 and as LAPACK Working Note 184
Uncontrolled Keywords: CELL BE, iterative refinement, mixed-precision algorithms, Cholesky factorization
Subjects: MSC 2010, the AMS's Mathematics Subject Classification > 65 Numerical analysis
MSC 2010, the AMS's Mathematics Subject Classification > 68 Computer science
Depositing User: Ms Lucy van Russelt
Date Deposited: 03 Jul 2007
Last Modified: 08 Nov 2017 18:18
URI: https://eprints.maths.manchester.ac.uk/id/eprint/821

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