检索结果-南通市图书馆

BLOCK iterative methods FOR LINEAR ALGEBRAIC EQUATION AND DOMAIN DECOMPOSITION METHOD FOR INCOMPRESSIBLE VISCOUS FLOW

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2002年第4期14卷 73-80页

作者： Ren, An-Lu Zou, Jian-Feng Zhou, Yong-Xia Li, Guang-Wang Dept. of Mech. Zhejiang Univ. Hangzhou 310027 China

It was proved numerically that the Domain Decomposition Method CDDM) with one layer overlapping grids is identical to the block iterative method of linear algebra equations. The results obtained by using DDM could be in reasonable agreement with the results of full-domain simulation. With the three dimensional solver developed by the authors, the flow field in a pipe was simulated by using the full-domain DDM with one layer overlapping grids and with patched grids respectively. Both of the two cases led to the convergent solution. Further research shows the superiority of the DDM with one layer overlapping grids to the DDM with patched grids. A comparison between the numerical results obtained by the authors and the experimental results given by Enayet[3] shows that the numerical results are reasonable.

关键词： Computational fluid dynamics Computer simulation iterative methods Linear equations Viscous flow

Dynamical Comparison of Several Third-Order iterative methods for Nonlinear Equations

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2021年第5期67卷 1951-1962页

作者： Obadah Said Solaiman Samsul Ariffin Abdul Karim Ishak Hashim Department of Mathematical Sciences Faculty of Science&TechnologyUniversiti Kebangsaan MalaysiaBangi Selangor43600Malaysia Department of Fundamental and Applied Sciences Center for Smart Grid Energy Research(CSMER)Institute of Autonomous SystemUniversiti Teknologi PETRONASBandar Seri IskandarSeri IskandarPerak DR32610Malaysia

There are several ways that can be used to classify or compare iterative methods for nonlinear equations,for instance;order of convergence,informational efficiency,and efficiency *** this work,we use another way,namely the basins of attraction of the *** purpose of this study is to compare several iterative schemes for nonlinear *** the selected schemes are of the third-order of convergence and most of them have the same efficiency *** comparison depends on the basins of attraction of the iterative techniques when applied on several polynomials of different *** a comparison,we determine the CPU time(in seconds)needed by each scheme to obtain the basins of attraction,besides,we illustrate the area of convergence of these schemes by finding the number of convergent and divergent points in a selected range for all *** confirm the fact that basins of attraction differ for iterative methods of different orders,furthermore,they vary for iterative methods of the same order even if they have the same efficiency ***,this leads to the need for a new index that reflects the real efficiency of the iterative scheme instead of the commonly used efficiency index.

关键词： Nonlinear equations iterative methods basins of attraction order of convergence

Quadrature Based Optimal iterative methods with Applications in High-Precision Computing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,methods and Applications) 2012年第4期5卷 592-601页

作者： Sanjay Kumar Khattri Stord/Haugesund University College Department of EngineeringHaugesundNorway

We present a simple yet effective and applicable scheme,based on quadrature,for constructing optimal iterative *** to the,still unproved,Kung-Traub conjecture an optimal iterative method based on n+1 evaluations could achieve a maximum convergence order of *** quadrature,we develop optimal iterative methods of orders four and *** scheme can further be applied to develop iterative methods of even higher *** results demonstrate that the developed methods are efficient as compared with many well known methods.

关键词： iterative methods fourth order eighth order quadrature Newton convergence nonlinear optimal

Superattracting cycles for some Newton type iterative methods

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2011年第3期54卷 539-544页

作者： AMAT Sergio BUSQUIER Sonia NAVARRO Emilie PLAZA Sergio Departamento de Matemtica Aplicada y Estadistica Universidad Politécnica de Cartagena Ecole Généraliste d'Ingénieurs de Marseille (EGIM) Departamento de Matemticas Facultad de Ciencias Universidad de Santiago de Chile

The paper is devoted to the analysis of certain dynamical properties of a family of iterative Newton type methods used to find roots of non-linear equations. We present a procedure for constructing polynomials in such a way that superattracting cycles of any prescribed length occur when these iterative methods are applied. This paper completes the study begun in Amat, Bermúclez, Busquier, et al., (2009).

关键词： iterative methods (super)attracting cycles dynamics

Distributed Least-Squares iterative methods in Large-Scale Networks:A Survey

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2017年第3期15卷 37-45页

作者： SHI Lei ZHAO Liang SONG Wenzhan Goutham Kamath WU Yuan LIU Xuefeng Georgia State University Atlanta GA 30302 USA Georgia Gwinnett College Lawrenceville GA 30043 USA University of Georgia Athens GA 30602 USA Zhejiang University of Technology Hangzhou 310023 China The Hong Kong Polytechnic University Hong Kong China

Many science and engineering applications involve solvinga linear least-squares system formed from some field measurements. In the distributed cyber-physical systems(CPS),each sensor node used for measurement often only knowspartial independent rows of the least-squares system. To solve the least-squares all the measurements must be gathered at a centralized location and then perform the computa-tion. Such data collection and computation are inefficient because of bandwidth and time constraints and sometimes areinfeasible because of data privacy concerns. iterative methods are natural candidates for solving the aforementionedproblem and there are many studies regarding this. However,most of the proposed solutions are related to centralized/parallel computations while only a few have the potential to beapplied in distributed networks. Thus distributed computations are strongly preferred or demanded in many of the realworld applications, e.g. smart-grid, target tracking, etc. Thispaper surveys the representative iterative methods for distributed least-squares in networks.

关键词： distributed computing iterative methods least⁃squares mesh network

在线全文

学校读者我要写书评

暂无评论

线性方程组迭代方法残差光滑技术的一个推广

高等学校计算数学学报 2000年第2期22卷 131-140页

作者：李春光徐成贤西安交通大学数学系!西安710049 郑州大学数学系!郑州450052

The residual norm behavior of an iterative method for solving linear systems Ax=b is of particular importance. Residual smoothing technique is named for the strategy that improve the residual norm behavior simply via a two term weighted mean of some two points (iterates). A generalization from the two point residual smoothing technique to m point residual smoothing, which is obtained by a m term weighted mean of some m points, is studied and explored. A new hybrid iterative method combining this generalization with restarting approach is presented. Results of numerical experiments comparing the generalization with the original residual smoothing are reported.

关键词： iterative methods Krylov subspace methods residual smoothing BCG methods hybrid methods.

求解大型稀疏最小二乘问题的2—块PSD型迭代法

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

高等学校计算数学学报 1999年第1期21卷 61-70页

作者：张志华郑南宁西安交通大学人机所!西安　710049

Recently, BSOR BAOR and BSSOR for solving large sparse least-square problems have widely been studied. However, up to now, the optimum 3-BAOR and BSSOR (3-BSSOR and 2-BSSOR) have not been solved. PJ and SSOR are two special schemes of PSD’s. In this paper, we have respectively discussed 2-block iterative algorithms for the three iterative methods. Furthermore, their convergent regions, and formulas of their optimum parameters and the corresponding spectral radii are given respectively. Therefore, the difficult problem of the optimum 2-BSSOR has successfuly been settled. It is showed .that BSSOR is an a optimum special scheme of BPSD’s in the paper.

关键词： iterative methods convergent region optimum parameter spectral radius.

TOTAL GENERALIZED MINIMUM BACKWARD ERROR ALGORITHM FOR SOLVING NONSYMMETRIC LINEAR SYSTEMS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1998年第6期16卷 539-550页

作者： Zhi-hao Cao (Dearptment of Mathematics, Fudan University, Shanghai 200433, China) 复旦大学数学系上海

This paper extendes the results by E.M. Kasenally([7]) on a Generalized Minimum Backward Error Algorithm for nonsymmetric linear systems Ax = b to the problem in which pertubations are simultaneously permitted on A and b. The approach adopted by Kasenally has been to view the approximate solution as the exact solution to a perturbed linear system in which changes are permitted to the matrix A only. The new method introduced in this paper is a Krylov subspace iterative method which minimizes the norm of the perturbations to both the observation vector b and the data matrix A and has better performance than the Kasenally's method and the restarted GMRES method([12]). The minimization problem amounts to computing the smallest singular value and the corresponding right singular vector of a low-order upper-Hessenberg matrix. Theoratical properties of the algorithm are discussed and practical implementation issues are considered. The numerical examples are also given.

关键词： nonsymmetric linear systems iterative methods backward error

SAR imaging method for sea scene target based on improved phase retrieval algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2016年第6期27卷 1176-1182页

作者： Hongyin Shi Qiuxiao Zhou Xiaoyan Yang Qiusheng Lian School of Information Science and Engineering Yanshan University

Due to the influence of the platform random motion and electromagnetic propagation in turbulent media, the synthetic aperture radar (SAR) high resolution imaging for the sea scenes where there are large amounts of water returns with some target (land) returns is very difficult. To solve this problem, a SAR imaging method based on the improved phase retrieval (PR) algorithm is proposed. First, a filter is added to the conventional PR algorithm which can reduce the influence of water returns on the reconstruction of the targets and improve the reconstruction result of the targets. Then, the corrupted phase of the Fourier transform of the intensity image in the iterative process, which can improve the stability of the iterative algorithm, is used to reduce the recovery errors, and a better recovery performance is achieved. Finally, several experiments are performed to demonstrate the advantages of the proposed method. © 2016 Beijing Institute of Aerospace Information.

关键词： Image reconstruction iterative methods Radar Synthetic aperture radar