求解特征值反问题的同伦方法

§1.引言 本文讨论经典的加法问题,即 问题A.给定一个n阶实对称矩阵A和n个实数λ_1,…,λ_n,求n维实向量x=(x_,…,x_n)~T,使得A+diag(x_1,…,x_n)的特征值是λ_1,…,λ_n。 求解问题A的数值方法已有很多,一般是先把问题A化为一个等价的非线性方程组,然后用Newton法求解相应的非线性方程组.在[6]中,Friedland等对这方面的工     

利用改进的同伦算法求解特征值问题

矩阵特征值问题是机器学习、数据处理以及工程分析和计算中经常需要解决的问题之一.同伦算法是求解矩阵特征值的经典方法;自动微分可以有效、快速地计算出大规模问题相关函数的导数项,并且可以达到机器精度.充分利用自动微分的优点,设计自动微分技术与同伦算法相结合的方法求解矩阵特征值问题.数值实验验证了该算法的有效性.     

解广义特征值反问题的同伦方法

1.引言 我们讨论下列广义特征值反问题: (G)已知B是n×n阶对称半正定矩阵,λ=(λ_1,…,λ_(2n-1))~T∈R~(2n-1),且{λ_i}~(n_3),和{λ_i}_(n+1)~(2n-1)严格交错。问题是欲求一个实对称三对角n×n阶矩阵A,使得λ_1…,λ_n是Ax=λBx的特征值,λ_(n+1),…,λ_(2n-1)是A_(n-1)x=λB_(n-1)x的特征值,其中A_(n-1),B_(n-1)分别是矩阵A,B的前n-1阶主子阵。     

关于加法逆特征值问题

１．引言 设Ａ（ｃ）＝（ａｉｊ（ｃ））是ｎ阶实矩阵,其元素ａｉｊ（ｃ）（ｉ,ｊ＝１,…,ｎ）是参变量ｃ＝（Ｃ１,…,ｃｎ）Ｔ的实解析函数,λ１（ｃ）,…,λｎ（Ｃ）是矩阵Ａ（ｃ）的特征值,λ１,…,λｎ是给定的实数,代数特征值反问题［４］就是研究如何求解实的ｃ,使Ａ（ｃ）的特征值为给定的λ１,…,λｎ． 假设给定的ｎ个数λ１,…,λｎ互异,且问题的解存在（解不存在时可考虑某种形式的最小二乘解）,过去的研究一般是直接研究或将问题转化为如下等价的非线性方程组 ｄｅｔ（Ａ（ｃ卜人Ｉ）一０, ｉ＝ １,…,…     

非线性互补问题的凝聚同伦方法

给出凝聚函数的性质,利用凝聚函数构造同伦方程,证明了同伦路径的存在性,有界性和收敛性,给出非单调函数拟P_*-映射满足严格可行条件时所对应的互补问题的可解性.     

一类特殊矩阵的逆特征值问题

本文主要讨论如下形式矩阵的逆特征值问题:即对给定n个实数λ_1>λ_2>…>λ_2与n-1个实数μ_1>μ_2>…>μ_(n-1),满足λ_1>μ_1>λ_2>…>λ_(n-1)>μ_(n-1)>λ_n,在α_2>α_3>…>α_(n-1)的条件下,存在唯一的一个矩阵A_n是以λ_i为其特征值;且其截边矩阵的特征值为μ_1,μ_2,…,μ_(n-1).     

HIV病毒传播的动力学研究的同伦映射解法

研究了艾滋病病毒的传播的一个动力学模型．利用同伦映射理论和方法得到了HIV流行性传染病区域的人群传播规律．     

Inverse Eigenvalue Problem in Structural Dynamics Design

1 Introduction Structural dynamics design is to design a structure subject to the dynamic characteristics re- quirement, i.e., determine physical and geometrical parameters such that the structure has the given frequencies and (or) mode shapes. This problem often arises in engineering connected with vibration. Recently, Joseph [1], Li et al. [2,3] converted the structural dynamics design to the following inverse eigenvalue problem. GIEP Let x = (x1, , xm)T , and let A(x) and B(x) be real n…     

Inverse Eigenvalue Problems in Structural Dynamics

We consider the numerical solution of inverse eigenvalue problems (IEP). Two different formulations are used. The methods are applied to a certain mechanical system. Due to the special structure of the mass and stiffness matrix we benefit from a secular equation. The roots of that equation are the eigenvalues of the system. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A Solution of Inverse Eigenvalue Problems for Unitary Hessenberg Matrices

Let H∈Cn×n be an n×n unitary upper Hessenberg matrix whose subdiagonal elements are all positive. Partition H as H=[H11 H12 H21 H22],(0.1) where H11 is its k×k leading principal submatrix; H22 is the complementary matrix of H11. In this paper, H is constructed uniquely when its eigenvalues and the eigenvalues of (H|^)11 and (H|^)22 are known. Here (H|^)11 and (H|^)22 are rank-one modifications of H11 and H22 respectively.     

Newton's Method for a Generalized Inverse Eigenvalue Problem

A kind of generalized inverse eigenvalue problem is proposed which includes the additive, multiplicative and classical inverse eigenvalue problems as special cases. Newton's method is applied, and a local convergence analysis is given for both the distinct and the multiple eigenvalue cases. When the multiple eigenvalues are present we show how to state the problem so that it is not over-determined, and discuss a Newton-method for the modified problem. We also prove that the modified method retains quadratic convergence, and present some numerical experiments to illustrate our results. © 1997 by John Wiley & Sons, Ltd.     

对称矩阵与反对称矩阵广义特征值反问题的拓广

定义了上三角等次对角线矩阵和上三角交错次对角线矩阵;讨论了矩阵方程AX-XA=0的对称解与AX XA=0的反对称解.在此基础上考虑了以下问题的可解性:给定A∈Rn×m,D∈Rm×m,分别求X,Y∈SRn×n和X,Y∈ASRn×n,使得XA=YDA.     

On the Solution of Inverse Problems for Generalized Oxygen Consumption

We present the solution of some inverse problems for one-dimensional free boundary problems of oxygen consumption type, with a semilinear convection-diffusion-reaction parabolic equation. Using a fixed domain transformation (Landau's transformation) the direct problem is reduced to a system of ODEs. To minimize the objective functionals in the inverse problems, we approximate the data by a finite number of parameters with respect to which automatic differentiation is applied.     

(i,p) -同伦逆和群同伦逆

该文在点标拓扑空间范畴中引进了(i,p)-同伦逆和群同伦逆的概念,并讨论了它们存在的条件和性质.     

The Inexact Newton-Like Method for Inverse Eigenvalue Problem

In this paper, we consider using the inexact Newton-like method for solving inverse eigenvalue problem. This method can minimize the oversolving problem of Newton-like methods and hence improve the efficiency. We give the convergence analysis of the method, and provide numerical tests to illustrate the improvement over Newton-like methods.     

求解Brouwer不动点问题的改进同伦方法

In this paper,we modify the homotopy method(proposed by Yu and Lin,Appl.Math.Comput.,74(1996),65)and hence make the modified method be able to solve Brouwer fixed-point problems in a broader class of nonconvex subsets in R~n.In addition,a simple example is given to show the effectiveness of the modified method.     

求解一类非线性规划的连续同伦方法(英文)

In this paper we present a homotopy continuation method for finding the Karush-Kuhn-Tucker point of a class of nonlinear non-convex programming problems. Two numerical examples are given to show that this method is effective. It should be pointed out that we extend the results of Lin et al. （see Appl. Math. Comput., 80（1996）, 209-224） to a broader class of non-convex programming problems.