Parallel tiled QR factorization for multicore architectures

Alfredo Buttari, Julien Langou, Jakub Kurzak, Jack Dongarra

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations

Abstract

As multicore systems continue to gain ground in the High Performance Computing world, linear algebra algorithms have to be reformulated or new algorithms have to be developed in order to take advantage of the architectural features on these new processors. Fine grain parallelism becomes a major requirement and introduces the necessity of loose synchronization in the parallel execution of an operation. This paper presents an algorithm for the QR factorization where the operations can be represented as a sequence of small tasks that operate on square blocks of data. These tasks can be dynamically scheduled for execution based on the dependencies among them and on the availability of computational resources. Compared to the standard approach, say with LAPACK, may result in an out of order execution of the tasks which will completely hide the presence of intrinsically sequential tasks in the factorization. Performance comparisons are presented with the LAPACK algorithm for QR factorization where parallelism can only be exploited at the level of the BLAS operations.

Original languageEnglish
Title of host publicationParallel Processing and Applied Mathematics - 7th International Conference, PPAM 2007, Revised Selected Papers
Pages639-648
Number of pages10
DOIs
StatePublished - 2008
Event7th International Conference on Parallel Processing and Applied Mathematics, PPAM 2007 - Gdansk, Poland
Duration: Sep 9 2007Sep 12 2007

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume4967 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference7th International Conference on Parallel Processing and Applied Mathematics, PPAM 2007
Country/TerritoryPoland
CityGdansk
Period09/9/0709/12/07

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