非光滑方程组牛顿法的全局收敛性分析

通过定义一种新的*-微分,本文给出了局部Lipschitz非光滑方程组的牛顿法,并对其全局收敛性进行了研究.该牛顿法结合了非光滑方程组的局部收敛性和全局收敛性.最后,我们把这种牛顿法应用到非光滑函数的光滑复合方程组问题上,得到了较好的收敛性.     

求解非线性方程组的L-M方法

本文研究了求解奇异非线性方程组的Levenberg-Marquardt方法的收敛性.利用选取新的迭代参数求解非线性方程组的L-M方法,获得点列的超线性收敛性和二阶收敛性,并把试验结果与文献[19,20]的结果进行了比较.     

海洋动力学中二维黏性原始方程组解对热源的收敛性

考虑了在一个柱形区域上的海洋动力学中二维黏性方程组解的收敛性.在此模型中存在一个关键的参数就是热源,众多周知,它的存在可能会使流体内层之间出现共振从而导致不稳定.因此,通过推导方程组的先验界,得到了方程组的解对热源自身的收敛性.     

GSOR,GAOR,GSSOR和GSAOR

M.M.Martins于1986年提出了解线性代数方程组的MSOR方法,其实这种方法就是[2]中GAOR方法的特例,而且在[2]中还讨论了GSAOR方法,收敛性条件只含Jacobi迭代矩阵的谱半径,不含方程组的系数,特别是建立了GAOR或GSAOR收敛和方程组系数A为H阵的等价性,故所得结果比较好.又[1]中的定理1也是[4]中一个     

一阶拟线性双曲型方程组慢时间尺度下的零松弛极限

本文考虑慢时间尺度下带松弛时间源项的高维一阶拟线性双曲型方程组Cauchy问题的光滑解,这个方程组具有非守恒的形式;假设它是部分耗散的对称双曲组,当松弛时间趋于零时,它在形式上趋于一个两阶非线性抛物型方程组.在双曲型方程组满足一些结构性的假设下,本文得到了两个收敛性的结果.对于大初值,本文证明了双曲型方程组在一个对松弛时间一致的时间区间上的收敛性,当初值在常数平衡态附近变化时,证明了光滑解关于时间的一致整体存在性和双曲型方程组的整体收敛性.本文也给出一些有物理背景的例子来作为这些结果的应用.     

解非线性方程组松弛法的大范围收敛性

热知,松弛法是解多变量方程组的有效方法之一,它广泛用于求解由偏微分方程离散化导出的方程组。1962年与1963年S.Schechter与作者曾各自独立地研究并发表了解非线性方程组的逐步松弛法(SOR方法)的收敛性,作者还研究了其它松弛程序的收敛性并且给出了敛速估计,1968年S.Schechter也进一步研究了其它松弛程序并估计了收敛速度。前述结果以及后来其它工作均假定方程组具有连续的Jacobi矩阵存在(参考[4])。本文在不假定Jacobi矩阵存在的条件下建立了松弛法大范围收敛性理沦,证明SOR—Newton法,SOR—弦截法及SOR—Steffensen法的收敛性,并给出了敛速估计,从而扩大了这类方法的适用范围,利用所得到的结果解决了描写受控核反应方程的差分及有限元模拟的松弛法的收敛性。     

求解非线性互补问题的一类光滑Broyden-like方法

非线性互补问题可以等价地转换为光滑方程组来求解. 基于一种新的非单调线搜索准则, 提出了求解非线性互补问题等价光滑方程组的一类新的非单调光滑 Broyden-like 算法.在适当的假设条件下, 证明了该算法的全局收敛性与局部超线性收敛性. 数值实验表明所提出的算法是有效的.     

一类强耦合的奇异摄动对流扩散方程组的移动网格方法（英文）

本文研究一类强耦合的奇异摄动对流扩散方程组的移动网格方法.首先,利用迎风有限差分格式对方程组进行离散.然后,推出数值解的后验误差估计,并以此设计出相应的自适应网格生成算法.同时,证明数值解具有一阶一致收敛性.最后,数值实验验证了本文移动网格方法的一致收敛性.     

阻尼Gauss-Newton方法解非线性不等式组

本文研究了非线性不等式组的求解问题.利用了阻尼Gauss-Newton方法求解非线性方程组,获得了该算法的全局收敛性,推广了Gauss-Newton法在解非线性方程组方面的应用.     

等式约束非线性规划的一种线性代数方程组解法

本文提出了一种求解等式约束非线性规划的新方法－线性代数方程组求解方法。我们证明了该算法具有全局收敛性和局部二阶收敛性。     

三阶方向牛顿法的收敛性

通过递推关系,证明了解希尔伯特空间上的实系数非线性方程组的三阶方向牛顿法的半局部收敛性,给出了解的存在性以及先验误差界,最后计算出一些数值结果来证明我们的结论.     

Semilocal convergence of a multipoint fourth-order super-Halley method in Banach spaces

In this paper, we study a variant of the super-Halley method with fourth-order convergence for nonlinear equations in Banach spaces. We make an attempt to establish the semilocal convergence of this method by using recurrence relations. The recurrence relations for the method are derived and then an existence-uniqueness theorem is given to establish the R-order of the method to be four and a priori error bounds. Finally, some numerical applications are presented to demonstrate our approach.     

Semilocal convergence of a sixth-order Jarratt method in Banach spaces

In this paper, we study the semilocal convergence for a sixth-order variant of the Jarratt method for solving nonlinear equations in Banach spaces. The semilocal convergence of this method is established by using recurrence relations. We derive the recurrence relations for the method, and then prove an existence-uniqueness theorem, along with a priori error bounds which demonstrates the R-order of the method. Finally, we give some numerical applications to demonstrate our approach.     

Recurrence relations for semilocal convergence of a Newton-like method in Banach spaces

The aim of this paper is to establish the semilocal convergence of a multipoint third order Newton-like method for solving F(x)=0 in Banach spaces by using recurrence relations. The convergence of this method is studied under the assumption that the second Fréchet derivative of F satisfies Hölder continuity condition. This continuity condition is milder than the usual Lipschitz continuity condition. A new family of recurrence relations are defined based on the two new constants which depend on the operator F. These recurrence relations give a priori error bounds for the method. Two numerical examples are worked out to demonstrate the applicability of the method in cases where the Lipschitz continuity condition over second derivative of F fails but Hölder continuity condition holds.     

Remark on the convergence of the midpoint method under mild differentiability conditions

We establish a convergence theorem for the Midpoint method using a new system of recurrence relations. The purpose of this note is to relax its convergence conditions. We also given an example where our convergence theorem can be applied but other ones cannot.     

A study of the influence of center conditions on the domain of parameters of Newton’s method by using recurrence relations

This paper focuses on the importance of center conditions on the first derivative of the operator involved in the solution of nonlinear equations by Newton’s method when the semilocal convergence of the method is established from the technique of recurrence relations.     

Convergence analysis for the Secant method based on new recurrence relations

A new convergence theorem for the Secant method in Banach spaces based on new recurrence relations is established for approximating a solution of a nonlinear operator equation. It is assumed that the divided difference of order one of the nonlinear operator is Lipschitz continuous. The convergence conditions differ from some existing ones and are easily satisfied. The results of the paper are justified by numerical examples that cannot be handled by earlier works.     

Improving a method for computing non-dominant solutions of certain second-order recurrence relations of Poincaré-type

Summary In this paper we present a method of convergence acceleration for the calculation of non-dominant solutions of second-order linear recurrence relations for which the coefficients satisfy certain asymptotic conditions. It represents an improvement of the method recently proposed by Jacobsen and Waadeland [3, 4] for limit periodic continued fractions. For continued fractions the method corresponds to a repeated application of the Bauer-Muir transformation. Some examples and a generalization to non-homogeneous recurrence relations are given.     

Semilocal Convergence of a Class of Modified Super-Halley Methods in Banach Spaces

In this paper, we consider the semilocal convergence of a class of modified super-Halley methods for solving nonlinear equations in Banach spaces. The semilocal convergence of this class of methods is established by using recurrence relations. We construct a system of recurrence relations for the methods, and based on it, we prove an existence–uniqueness theorem that shows the R-order of the methods.     

Semilocal convergence for Halley’s method under weak Lipschitz condition

The semilocal convergence properties of Halley’s method for nonlinear operator equations are studied under the hypothesis that the second derivative satisfies some weak Lipschitz condition. The method employed in the present paper is based on a family of recurrence relations which will be satisfied by the involved operator. An application to a nonlinear Hammerstein integral equation of the second kind is provided.