Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Iterated Gauss-Seidel GMRES

Journal Article · · SIAM Journal on Scientific Computing
DOI:https://doi.org/10.1137/22M1491241· OSTI ID:2367546

The GMRES algorithm of Saad and Schultz [SIAM J. Sci. Stat. Comput., 7 (1986), pp. 856-869] is an iterative method for approximately solving linear systems Ax = b, with initial guess x0 and residual r0 = b Ax0. The algorithm employs the Arnoldi process to generate the Krylov basis vectors (the columns of Vk ). It is well known that this process can be viewed as a QR factorization of the matrix Bk = [r0, AVk] at each iteration. Despite an O (..epsilon..)..kappa.. (Bk ) loss of orthogonality, for unit roundoff ..epsilon..and condition number ..kappa.. , the modified Gram-Schmidt formulation was shown to be backward stable in the seminal paper by Paige et al. [SIAM J. Matrix Anal.Appl., 28 (2006), pp. 264-284]. We present an iterated Gauss-Seidel formulation of the GMRES algorithm (IGS-GMRES) based on the ideas of Ruhe [Linear Algebra Appl., 52 (1983), pp. 591-601] and Swirydowicz et al. [Numer. Linear Algebra Appl., 28 (2020), pp. 1-20]. IGS-GMRES maintains orthogonality to the level O (..epsilon..)..kappa.. (Bk ) or O (..epsilon..), depending on the choice of one or two iterations; for two Gauss-Seidel iterations, the computed Krylov basis vectors remain orthogonal to working accuracy and the smallest singular value of Vk remains close to one. The resulting GMRES method is thus backward stable. We show that IGS-GMRES can be implemented with only a single synchronization point per iteration, making it relevant to large-scale parallel computing environments. We also demonstrate that, unlike MGS-GMRES, in IGS-GMRES the relative Arnoldi residual corresponding to the computed approximate solution no longer stagnates above machine precision even for highly nonnormal systems.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Science (SC); USDOE National Nuclear Security Administration (NNSA); Exascale Computing Project (ECP)
DOE Contract Number:
AC36-08GO28308
OSTI ID:
2367546
Report Number(s):
NREL/JA-2C00-90005; MainId:91783; UUID:fabdd5ba-702e-49d1-8b6c-a52adae0bcb7; MainAdminId:72688
Journal Information:
SIAM Journal on Scientific Computing, Journal Name: SIAM Journal on Scientific Computing Journal Issue: 2 Vol. 46
Country of Publication:
United States
Language:
English

References (25)

The Stability of Block Variants of Classical Gram--Schmidt journal January 2021
Modified Gram-Schmidt (MGS), Least Squares, and Backward Stability of MGS-GMRES journal January 2006
Block Gram-Schmidt algorithms and their stability properties journal April 2022
Rounding error analysis of the classical Gram-Schmidt orthogonalization process journal May 2005
The Design and Implementation of hypre, a Library of Parallel High Performance Preconditioners book January 2006
Solving linear least squares problems by Gram-Schmidt orthogonalization journal March 1967
Numerical behaviour of the modified gram-schmidt GMRES implementation journal September 1997
Accuracy and Stability of Numerical Algorithms book January 2002
The Worst-Case GMRES for Normal Matrices journal January 2004
Theory of Inexact Krylov Subspace Methods and Applications to Scientific Computing journal January 2003
Spectra and Pseudospectra book January 2005
Numerics of Gram-Schmidt orthogonalization journal January 1994
Numerical stability of GMRES journal September 1995
Numerical aspects of gram-schmidt orthogonalization of vectors journal July 1983
GMRES: A Generalized Minimal Residual Algorithm for Solving Nonsymmetric Linear Systems journal July 1986
The Accuracy of Solutions to Triangular Systems journal October 1989
Using Jacobi iterations and blocking for solving sparse triangular systems in incomplete factorization preconditioning journal September 2018
A Krylov--Schur Algorithm for Large Eigenproblems journal January 2002
Bounds for iterates, inverses, spectral variation and fields of values of non-normal matrices journal December 1962
Low-synch Gram–Schmidt with delayed reorthogonalization for Krylov solvers journal September 2022
A Rank- k Update Procedure for Reorthogonalizing the Orthogonal Factor from Modified Gram--Schmidt journal January 2004
Low synchronization Gram–Schmidt and generalized minimal residual algorithms journal October 2020
Loss and Recapture of Orthogonality in the Modified Gram–Schmidt Algorithm journal January 1992
Residual and Backward Error Bounds in Minimum Residual Krylov Subspace Methods journal January 2002
Implementation of the GMRES Method Using Householder Transformations journal January 1988

Similar Records

Neumann Series in MGS-GMRES and Inner-Outer Iterations: Preprint
Conference · Tue Feb 08 23:00:00 EST 2022 · OSTI ID:1845270

Low-synch Gram–Schmidt with delayed reorthogonalization for Krylov solvers
Journal Article · Thu Sep 01 00:00:00 EDT 2022 · Parallel Computing · OSTI ID:1872059