Journal ArticleDOI
Accelerated Hermitian and skew-Hermitian splitting iteration methods for saddle-point problems
Zhong-Zhi Bai,Gene H. Golub +1 more
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TLDR
These methods involve two iteration parameters whose special choices can recover the known preconditioned HSS iteration methods, as well as yield new ones, and show that the new methods converge unconditionally to the unique solution of the saddle-point problem.Abstract:
We establish a class of accelerated Hermitian and skew-Hermitian splitting (AHSS) iteration methods for large sparse saddle-point problems by making use of the Hermitian and skew-Hermitian splitting (HSS) iteration technique. These methods involve two iteration parameters whose special choices can recover the known preconditioned HSS iteration methods, as well as yield new ones. Theoretical analyses show that the new methods converge unconditionally to the unique solution of the saddle-point problem. Moreover, the optimal choices of the iteration parameters involved and the corresponding asymptotic convergence rates of the new methods are computed exactly. In addition, theoretical properties of the preconditioned Krylov subspace methods such as GMRES are investigated in detail when the AHSS iterations are employed as their preconditioners. Numerical experiments confirm the correctness of the theory and the effectiveness of the methods.read more
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Journal ArticleDOI
Optimal parameters in the HSS‐like methods for saddle‐point problems
TL;DR: The Hermitian and skew-Hermitian splitting iteration method and its accelerated variant for solving the large sparse saddle-point problems are investigated in detail, and the formulas for computing good iteration parameters are given under certain principle for optimizing the distribution of the eigenvalues.
Journal ArticleDOI
On inexact Hermitian and skew-Hermitian splitting methods for non-Hermitian positive definite linear systems
TL;DR: Optimal choices of the inner iteration steps in the IHSS( CG, Lanczos) and IH SS(CG, CGNE) iterations are discussed in detail by considering both global convergence speed and overall computation workload, and computational efficiencies of both inexact iterations are analyzed and compared deliberately.
Journal ArticleDOI
Constraint Preconditioners for Symmetric Indefinite Matrices
TL;DR: Numerical results show that, for a suitably chosen $(1,1)$ block-matrix, this constraint preconditioner outperforms the block-diagonal and theBlock-tridiagonal ones in iteration step and computing time when they are used to accelerate the GMRES method for solving these block two-by-two symmetric positive indefinite linear systems.
Journal ArticleDOI
On semi-convergence of parameterized Uzawa methods for singular saddle point problems☆
Bing Zheng,Zhong-Zhi Bai,Xi Yang +2 more
TL;DR: In this article, the optimal iteration parameters and the corresponding optimal semi-convergence factor for the parameterized Uzawa method were determined for solving singular saddle point problems under suitable restrictions on the involved iteration parameters.
Journal ArticleDOI
On semi-convergence of Hermitian and skew-Hermitian splitting methods for singular linear systems
TL;DR: Applications of the HSS iteration method as a preconditioner for Krylov subspace methods such as GMRES are investigated in detail, and an upper bound is obtained in terms of the largest and the smallest nonzero eigenvalues of the Hermitian part of the coefficient matrix.