Skip to main content
Log in

Treatment of near-breakdown in the CGS algorithm

  • Published:
Numerical Algorithms Aims and scope Submit manuscript

Abstract

Lanczos' method for solving the system of linear equationsAx=b consists in constructing a sequence of vectors (x k ) such thatr k =b−Ax k =P k (A)r 0 wherer 0=b−Ax 0.P k is an orthogonal polynomial which is computed recursively. The conjugate gradient squared algorithm (CGS) consists in takingr k =P 2k (A)r0. In the recurrence relation forP k , the coefficients are given as ratios of scalar products. When a scalar product in a denominator is zero, then a breakdown occurs in the algorithm. When such a scalar product is close to zero, then rounding errors can seriously affect the algorithm, a situation known as near-breakdown. In this paper it is shown how to avoid near-breakdown in the CGS algorithm in order to obtain a more stable method.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. R.E. Bank and T.F. Chan, A composite step bi-conjugate gradient algorithm for solving nonsymmetric systems, Numer. Algorithms, this issue.

  2. R.E. Bank and T.F. Chan, An analysis of the composite step bi-conjugate gradient algorithm for solving nonsymmetric systems, Numer. Math. 66 (1993) 295–319.

    Article  Google Scholar 

  3. C. Brezinski,Padé-Type Approximation and General Orthogonal Polynomials, ISNM vol. 50 (Birkhäser, Basel, 1980).

    Google Scholar 

  4. C. Brezinksi and M. Redivo-Zaglia,Extrapolation Methods. Theory and Practice (North-Holland, Amsterdam, 1991).

    Google Scholar 

  5. C. Brezinski and M. Redivo-Zaglia, A new presentation of orthogonal polynomials with applications to their computation. Numer. Algorithms 1 (1991) 207–221.

    Google Scholar 

  6. C. Brezinski and M. Redivo-Zaglia, Treatment of near-breakdown in the CGS algorithm, Publication ANO 257, Université des Sciences et Technologies de Lille (November 1991).

  7. C. Brezinski and M. Redivo-Zaglia, Hybrid procedures for solving linear systems, Numer. Math. 67 (1994) 1–19.

    Article  Google Scholar 

  8. C. Brezinski and M. Redivo-Zaglia, Breakdowns in the computation of orthogonal polynomials, in:Nonlinear Numerical Methods and Rational Approximation, ed. A. Cuyt, (Kluwer, Dordrecht, 1994) pp. 49–59.

    Google Scholar 

  9. C. Brezinski and M. Redivo-Zaglia, Look-ahead in Bi-CGSTAB and other methods for linear systems, to appear.

  10. C. Brezinski, M. Redivo-Zaglia and H. Sadok, Avoiding breakdown and near-breakdown in Lanczos type algorithms, Numer. Algorithms 1 (1991) 261–284.

    Google Scholar 

  11. C. Brezinski, M. Redivo-Zaglia and H. Sadok, Addendum to “Avoiding breakdown and near-breakdown in Lanczos type algorithms”, Numer. Algorithms 2 (1992) 133–136.

    MathSciNet  Google Scholar 

  12. C. Brezinski, M. Redivo-Zaglia and H. Sadok, A breakdown-free Lanczos type algorithm for solving linear systems, Numer. Math. 63 (1992) 29–38.

    Article  Google Scholar 

  13. C. Brezinski, M. Redivo-Zaglia and H. Sadok, Breakdowns in the implementation of the Lánczos method for solving linear systems, Comp. Math. Appl., to appear.

  14. C. Brezinski and H. Sadok, Lanczos type methods for solving systems of linear equations, Appl. Numer. Math. 11 (1993) 443–473.

    Article  Google Scholar 

  15. C. Brezinski and H. Sadok, Avoiding breakdown in the CGS algorithm, Numer. Algorithms 1 (1991) 199–206.

    Google Scholar 

  16. P.N. Brown, A theoretical comparison of the Arnoldi and GMRES algorithms, SIAM J. Sci. Stat. Comp. 12 (1991) 58–78.

    Article  Google Scholar 

  17. T.F. Chan and T. Szeto, A composite step conjugate gradients squared algorithm for solving nonsymmetric linear systems, Numer. Algorithms, this issue.

  18. J.M. Chesneaux, Study of the computing accuracy by using probabilistic approach, in:Contribution to Computer Arithmetic and Self-Validating Numerical Methods, ed. C. Ulrich (Baltzer, Basel, 1990) pp. 19–30.

    Google Scholar 

  19. J.M. Chesneaux, Stochastic arithmetic properties, in:Computational and Applied Mathematics, I, eds. C. Brezinski and U. Kulisch (North-Holland, Amsterdam, 1992), pp. 81–91.

    Google Scholar 

  20. J.M. Chesneaux and J. Vignes, Les fondements de l'arithmétique stochastique, C.R. Acad. Sci. Paris, I, 315 (1992) 1435–1440.

    Google Scholar 

  21. J.M. Chesneaux and J. Vignes, L'algorithme de Gauss en arithmétique stochastique, C. R. Acad. Sci. Paris, II, 316 (1993) 171–176.

    Google Scholar 

  22. A. Draux,Polynômes Orthogonaux Formels. Applications, LNM 974 (Springer, Berlin, 1983).

    Google Scholar 

  23. R. Fletcher, Conjugate gradient methods for indefinite systems, in:Numerical Analysis, ed. G.A. Watson, LNM 506 (Springer, Berlin, 1976) pp. 73–89.

    Google Scholar 

  24. R.W. Freund, M.H. Gutknecht and N.M. Nachtigal, An implementation of the look-ahead Lanczos algorithm for non-Hermitian matrices, SIAM J. Sci. Comp. 14 (1993) 137–158.

    Article  Google Scholar 

  25. M.H. Gutknecht, A completed theory of the unsymmetric Lanczos process and related algorithms, Part I, SIAM J. Matrix. Anal. Appl. 13 (1992) 594–639.

    Article  Google Scholar 

  26. M.H. Gutknecht, The unsymmetric Lanczos algorithms and their relations to Padé approximation, continued fractions and the qd algorithm, to appear.

  27. M.H. Gutknecht, Variants of BICGSTAB for matrices with complex spectrum, SIAM J. Sci. Comp. 14 (1993) 1020–1033.

    Article  Google Scholar 

  28. K.C. Jea and D.M. Young, On the simplification of generalized conjugate gradient methods for nonsymmetrizable linear systems, Lin. Alg. Appl. 52/53 (1983) 399–417.

    Google Scholar 

  29. W. Joubert, Generalized conjugate gradient and Lanczos methods for the solution of nonsymmetric systems of linear equations, Ph.D. Thesis, University of Texas at Austin, Austin (1990).

    Google Scholar 

  30. T.W. Körner,Fourier Analysis (Cambridge University Press, Cambridge, 1988).

    Google Scholar 

  31. C. Lanczos, An iteration method for the solution of the eigenvalue problem of linear differential and integral operators. J. Res. Natl. Bur. Stand. 45 (1950) 255–282.

    Google Scholar 

  32. C. Lanczos, Solution of systems of linear equations by minimized iterations, J. Res. Natl. Bur. Stand. 49 (1952) 33–53.

    Google Scholar 

  33. N.M. Nachtigal, S.C. Reddy and L.N. Trefethen, How fast are nonsymmetric matrix iterations?, SIAM J. Matrix Anal. Appl. 13 (1992) 778–795.

    Article  Google Scholar 

  34. B.N. Parlett, D.R. Taylor and Z.A. Liu, A look-ahead Lanczos algorithm for unsymmetric matrices, Math. Comp. 44 (1985) 105–124.

    Google Scholar 

  35. W. Schönauer,Scientific Computing on Vector Computers (North-Holland, Amsterdam, 1987).

    Google Scholar 

  36. P. Sonneveld, CGS, a fast Lanczos-type solver for nonsymmetric linear systems, SIAM J. Sci. Stat. Comp. 10 (1989) 36–52.

    Article  Google Scholar 

  37. H.A. Van der Vorst, The convergence behavior of preconditioned CG and CG-S, in:Preconditioned Conjugate Gradient Methods, eds. O. Axelsson and L.Yu. Kolotilina, LNM 1457 (Springer, Berlin, 1990) pp. 126–136.

    Google Scholar 

  38. H.A. Van der Vorst, BI-CGSTAB: a fast and smoothly converging variant of Bi-CG for the solution of nonsymmetric linear systems, SIAM J. Sci. Stat. Comp. 13 (1992) 631–644.

    Article  Google Scholar 

  39. J. Vignes, Review of stochastic approach to round-off error analysis and its applications, Math. Comp. Simul. 30 (1988) 481–491.

    Article  Google Scholar 

  40. P.K.W. Vinsome, Orthomin, an iterative method for solving sparse sets of simultaneous linear equations, in:Proc. 4th Symp. on Reservoir Simulation (Society of Petroleum Engineers of AIME, 1976), pp. 149–159.

  41. R. Weiss, Convergence behavior of generalized conjugate gradient methods, Thesis, University of Karlsruhe (1990).

  42. D.M. Young and K.C. Jea, Generalized conjugate-gradient acceleration of nonsymmetrizable iterative methods, Lin. Alg. Appl. 34 (1980) 159–194.

    Article  Google Scholar 

  43. L. Zhou and H.F. Walker, Residual smoothing techniques for iterative methods, SIAM J. Sci. Stat. Comp., to appear.

  44. R. Zippel,Effective Polynomial Computation, (Kluwer, Dordrecht, 1993).

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Additional information

Communicated by T.F. Chan

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brezinski, C., Redivo-Zaglia, M. Treatment of near-breakdown in the CGS algorithm. Numer Algor 7, 33–73 (1994). https://doi.org/10.1007/BF02141260

Download citation

  • Received:

  • Revised:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02141260

Keywords

AMS(MOS) subject classification

Navigation