Algorithm 830: Another Visit With Standard and Modified Givens Transformations and A Remark on Algorithm 539

Hanson, Richard J. and Hopkins, Tim (2004) Algorithm 830: Another Visit With Standard and Modified Givens Transformations and A Remark on Algorithm 539. ACM Transactions on Mathematical Software, 30 (1). pp. 86-94. ISSN 0098-3500. (Full text available)

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Official URL http://doi.acm.org/10.1145/974781.974786

Abstract

First we report on a correction and improvement to the Level 1 Blas routine srotmg for computing the Modified Givens Transformation (MG). We then, in the light of the performance of the code on modern compiler/hardware combinations, reconsider the strategy of supplying separate routines to compute and apply the transformation. Finally, we show that the apparent savings in multiplies obtained by using MG rather than the Standard Givens Transformation (SG) do not always translate into reductions in execution time.

Item Type:	Article
Uncontrolled keywords:	BLAS, Givens rotation, linear algebra, Fortran software
Subjects:	Q Science > QA Mathematics (inc Computing science) > QA 76 Software, computer programming,
Divisions:	Faculties > Science Technology and Medical Studies > School of Computing > Systems Architecture Group
Depositing User:	Mark Wheadon
Date Deposited:	24 Nov 2008 18:02
Last Modified:	08 Jul 2014 10:14
Resource URI:	https://kar.kent.ac.uk/id/eprint/14202 (The current URI for this page, for reference purposes)