نتایج جستجو برای: preconditioner

تعداد نتایج: 5222  

2014
CUI-XIA LI

Based on the work of Wang and Li [A new preconditioned AOR iterative method for L-matrices, J. Comput. Appl. Math. 229 (2009) 47-53], in this paper, a new preconditioner for the AOR method is proposed for solving linear systems whose coefficient matrix is an L-matrix. Several comparison theorems are shown for the proposed method with two preconditioners. It follows from the comparison results t...

1998
W. D. Turner J. E. Flaherty

This paper looks at the SSOR algorithm and shows that, under certain conditions, we can generate an approximation to the SSOR preconditioner using only one triangular solve. We show that this approximation can result in slightly increased iterations to convergence, but increased solution eeciency when used as a preconditioner for non-symmetric, indeenite systems of equations. The paper analyzes...

2017
Xinhui Shao Chen Li Tie Zhang Changjun Li X. H. SHAO C. LI T. ZHANG C. J. LI

The preconditioner for parameterized inexact Uzawa methods have been used to solve some indefinite saddle point problems. Firstly, we modify the preconditioner by making it more generalized, then we use theoretical analyses to show that the iteration method converges under certain conditions. Moreover, we discuss the optimal parameter and matrices based on these conditions. Finally, we propose ...

2002
P. Favati G. Lotti O. Menchi

The preconditioned conjugate gradient (CG) is often applied in image reconstruction as a regularizing method. When the blurring matrix has Toeplitz structure, the modified circulant preconditioner and the inverse Toeplitz preconditioner have been shown to be effective. We introduce here a preconditioner for symmetric positive definite Toeplitz matrices based on a trigonometric polynomial fit wh...

Journal: :SIAM J. Scientific Computing 1998
Michele Benzi Miroslav Tuma

This paper is concerned with a new approach to preconditioning for large sparse linear systems A procedure for computing an incomplete factorization of the inverse of a nonsymmetric matrix is developed and the resulting factorized sparse approximate inverse is used as an explicit preconditioner for conjugate gradient type methods Some theoretical properties of the preconditioner are discussed a...

2015
Yuqing Xie

A physically motivated near zone preconditioner is presented for solving the equations obtained from finite element method. Different from common sparse approximate inverse (SPAI) preconditioner, the proposed one gives the sparsity pattern based on a physical approximation. And its sparseness can be adjusted in different applications. The process of the algorithm needs low memory and CPU time, ...

2007
Martin Stoll Andy Wathen

The Bramble-Pasciak Conjugate Gradient method is a well known tool to solve linear systems in saddle point form. A drawback of this method in order to ensure applicability of Conjugate Gradients is the need for scaling the preconditioner which typically involves the solution of an eigenvalue problem. Here, we introduce a modified preconditioner and inner product which without scaling enable the...

ژورنال: اعتیاد پژوهی 2012
بیات, غلامرضا , حاجی ‏زاده, سهراب , سمنانیان, سعید , صفری, فاطمه , علویان, فیروزه , مظلوم, رهام , پورخلیلی, خلیل ,

Introduction: Hyperoxia is an easy access preconditioner which attracts the researcher to use it in the clinic. Drug dependence is a widespread prevalence among different societies and one of the confounding factors in many diseases. Among different drugs, morphine dependence has shown preconditioning effects. According to both widespread phenomenon of drug addiction and use of hyperoxia in the...

Journal: :International Journal of Computer Mathematics 2021

Recently, in (M. Masoudi, D.K. Salkuyeh, An extension of positive-definite and skew-Hermitian splitting method for preconditioning generalized saddle point problems, Computers \& Mathematics with Application, https://doi.org/10.1016/j.camwa.2019.10.030, 2019) an the positive definite (EPSS) iteration nonsingular problems has been presented. In this article, we study semi-convergence EPSS singul...

Journal: :Linear Algebra and its Applications 2004

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