ANZIAM J. 46(E) pp.C971--C986, 2005.

A note on the relation of Gaussian elimination to the conjugate directions algorithm

J. Tenne

S. W. Armfield

(Received 5 November 2004, revised 15 September 2005)

Abstract

This work examines the relation between Gaussian elimination and the conjugate directions algorithm [Hestenes and Steifel, 1952]. Analysis is extended to the case where the sequence of the conjugated vectors is modified, which is shown to result in reordering of the solution vector. Based on these analyses an algorithm is described which combines Gaussian elimination with a look-ahead algorithm. The purpose of the algorithm is to employ Gaussian elimination on a system of smaller order and to use this solution to approximate the solution of the original system. The algorithm was tested on a range of linear systems and performed well when the components in the solution vector varied by large magnitude.

Download to your computer

Authors

J. Tenne
S. W. Armfield
School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, Australia. mailto:joel.tenne@aeromech.usyd.edu.au, mailto:armfield@aeromech.usyd.edu.au

Published October 7, 2005. ISSN 1446-8735

References

  1. Owe Axelsson. Iterative Solution Methods. Cambridge University Press, Cambridge ; New York, 1994.
  2. Gene H. Golub and Dianne P. O'Leary. Some history of the conjugate gradient and {Lanczos} algorithms: 1948--1976. SIAM Review, 31(1):50--102, 1989.
  3. Gene H. Golub and Charles F. Van Loan. Matrix Computations. The Johns Hopkins University Press, Baltimore and London, third edition, 1996.
  4. Magnus R. Hestenes. Conjugate Direction Methods in Optimization. Number 12 in Applications of Mathematics. Springer-Verlag, New York; Heidelberg; Berlin, 1980.
  5. Magnus R. Hestenes. Conjugacy and gradients in variational theory and analysis. In Proceedings of the ACM Conference on History of Scientific and Numeric Computation, pages 71--90, New York, NY, USA, May 1987. ACM, ACM Press. http://doi.acm.org/10.1145/41579.41586
  6. Magnus R. Hestenes and Eduard Steifel. Methods of conjugate gradients for solving linear systems. Journal of Research of the National Bureau of Standards, 49(6):409--436, 1952.
  7. Llyod N. Trefethen and David Bau{, III}. Numerical Linear Algebra. SIAM, Philadelphia, PA, 1997.