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1.
1引言考虑用基于修正内罚函数的常微分方程(MBF-ODE)方法求解下列不等式约束极小化问题:其中fi∈c2:R,i=0,1,…,m.求解无约束极小化问题的ODE的一般形式是其中,φ(x)∈C1:ΩRn→R;s(x)∈C1:ΩRn→Rn且满足φ(x)>0,sT(x)f(x)<0,f(x)∈C1:Rn→R为目标函数.为便于用ODE方法求解(1.l),可藉助于罚函数将(1.l)变换为无约束极小化问题(见[7].但由于经典罚函数(CBF)在计算上有较大的困难,我们采用修正内罚函数(MBF).其基本思想是用…  相似文献   

2.
改进HS共轭梯度算法及其全局收敛性   总被引:14,自引:0,他引:14  
时贞军 《计算数学》2001,23(4):393-406
1.引 言 1952年 M.Hestenes和E.Stiefel提出了求解正定线性方程组的共轭梯度法[1].1964年R.Fletcher和C.Reeves将该方法推广到求解下列无约束优化问题: minf(x),x∈Rn,(1)其中f:Rn→R1为连续可微函数,记gk= f(xk),xk∈ Rn. 若点列{xk}由如下算法产生:其中 βk=[gTk(gk-gk-1)]/[dTk-1(gk-gk-1)].(Hestenes-Stiefel)  (4)则称该算法为 Hestenes—Stiefel共轭梯度算…  相似文献   

3.
1引言 考虑无约束优化问题其中f:Rn→R是一阶可微函数.求解(1)的非线性共轭梯度法具有如下形式:其中gk= f(xk),ak是通过某种线搜索获得的步长,纯量βk的选取使得方法(2)—(3)在f(x)是严格凸二次函数且采用精确线搜索时化为线性共轭梯度法[1].比较常见的βk的取法有Fletcher-Reeves(FR)公式[2]和Polak-Ribiere-Polyak(PRP)公式[3-4]等.它们分别为其中   取欧几里得范数.对于一般非线性函数,FR方法具有较好的理论收敛性[5-6],而…  相似文献   

4.
本文首先将文[1]中的BLD映射推广为弱(L1,L2)-BLD映射,并证明了如下正则性结果:存在两个可积指数 P1=P1(n,L1,L2)<n<q1=q1(n,L1,L2),使得对任意弱(L1,L2)-BLD映射f∈(Ω,Rn),都有f∈(Ω,Rn),即f为(L1,L2)-BLD映射.  相似文献   

5.
丁勇 《数学进展》1998,27(2):159-165
本文给出了一类带粗糙核的分数次振荡积分算子Tμ,Tμf(x)=∫RneiP(x,y)Ω(x-y)|x-y|n-μh(|x-y|)f(y)dy的加权Lp(Rn)有界性.这里P(x,y)是Rn×Rn上非平凡的实多项式,Ω∈Lq(Sn-1)为零阶齐次函数,且h(r)∈BV(R+).作为推论,证明了Tμ和BMO函数形成的高阶交换子Tμ,b,Tμ,bf(x)=∫RneiP(x,y)Ω(x-y)|x-y|n-μh(|x-y|)[b(x)-b(y)]mf(y)dy也是加权Lp(Rn)有界的,其中b(x)∈BMO(Rn),m∈Z+  相似文献   

6.
解非线性方程组的极大熵方法   总被引:10,自引:0,他引:10  
1引言考虑非线性方程组.其中F(x)=(f1(x)f2(x),f2(x),….fn(x))T.fi:Rn(i=1,…,n)是连续可微实值函数.求解非线性方程组的方法多种多样,例如.以Newton法为代表的迭代法及其一些变形.以及将问题(1.1)转换为f(F(x))的极小化问题,等等.Newton法在理论上有许多很好的结果,但在实际计算过程中,由于例如方法对初始点的严格要求以及计算F'(x)或其相应的近似估计的困难,使方法的使用受到一定的限制.用无约束优化方法求解(1.1)时,通常将其化成一个非线…  相似文献   

7.
双特征的Beltrami方程和拟正则映射   总被引:9,自引:2,他引:7  
郑神州 《数学学报》1997,40(5):745-750
设Ω为Rn上的一个区域,n2,对于具有双特征矩阵G(x),H(x)∈Ck,α(Ω,Rn),k1,0<α<1的Beltrami方程(1.4),建立了在Sobolev空间W1,nloc(Ω,Rn)上广义解的正则性:f(x)∈Ck+1,δloc(Ω),对某一δ:0<δ<1.  相似文献   

8.
带粗糙核的多线性振荡奇异积分   总被引:2,自引:0,他引:2  
胡国恩 《数学进展》1997,26(1):50-59
本文考虑多线性算子TAf(x)=∫RneiP(x,y)Ω(x-y)|x-y|n+mRm+1(A;x,y)f(y)dy,n2,其中P(x,y)是Rn×Rn中的实值多项式,Ω是零次齐次函数且满足m阶消失性条件,Rm+1(A;x,y)=A(x)-|α|mDαA(y)(x-y)α,对任何|α|=m,DαA∈BMO(Rn).证明了Ω∈Lq(Sn-1)且q>1时,对任何1<p<∞,‖TAf‖pC(n,m,p,degP)|α|=m‖DαA‖BMO‖f‖p  相似文献   

9.
岳优兰  王月山 《数学季刊》1999,14(2):108-110
§1. IntroductionAlocallyintegrablefunctionf(x)belongstoLipα(Rn),ifthereisaconstantC,suchthatforeveryx,y∈Rn|f(x)-f(y)|≤C|x-y|α  ThesmallestconstantCsatisfiesaboveiscalledLipschitznormoffandisdenotedbyyfy∧α.By[1],f∈Lipα(Rn)equivalenttof∈εα,2,whereεα,2=…  相似文献   

10.
杨富春 《数学杂志》1994,14(2):289-290
Banach空间上凸函数的Gateaux可微点杨富春云南大学本文总设定X是实Banach空间,D是x的非空开凸子集,j:D→R是连续的凸函数。f在x∈D的Gateaux导数,简称G导数。记在x点6可微若则记为f在x∈G(f;D)的G导数}。已经知道,...  相似文献   

11.
Global Newton methods for computing solutions of nonlinear systems of equations have recently received a great deal of attention. By using the theory of generalized equations, a homotopy method is proposed to solve problems arising in complementarity and mathematical programming, as well as in variational inequalities. We introduce the concepts of generalized homotopies and regular values, characterize the solution sets of such generalized homotopies and prove, under boundary conditions similar to Smale’s [10], the existence of a homotopy path which contains an odd number of solutions to the problem. We related our homotopy path to the Newton method for generalized equations developed by Josephy [3]. An interpretation of our results for the nonlinear programming problem will be given.  相似文献   

12.
关于广义Newton法的收敛性问题   总被引:4,自引:0,他引:4  
本文在较弱的条件下,证明了B-可微方程组的广义Newton法的局部超线性收敛性,为该算法直接应用于非线性规划问题、变分不等问题以及非线性互补问题等提供了理论依据。最后,本文给出了广义Newton法付之实践的具体策略。数值结果表明,算法是行之有效的。  相似文献   

13.
This paper will consider the problem of solving the nonlinear system of equations with block-triangular structure. A generalized block Newton method for semismooth sparse system is presented and a locally superlinear convergence is proved. Moreover, locally linear convergence of some parameterized Newton method is shown.  相似文献   

14.
We devise a new generalized univariate Newton method for solving nonlinear equations, motivated by Bregman distances and proximal regularization of optimization problems. We prove quadratic convergence of the new method, a special instance of which is the classical Newton method. We illustrate the possible benefits of the new method over the classical Newton method by means of test problems involving the Lambert W function, Kullback?CLeibler distance, and a polynomial. These test problems provide insight as to which instance of the generalized method could be chosen for a given nonlinear equation. Finally, we derive a closed-form expression for the asymptotic error constant of the generalized method and make further comparisons involving this constant.  相似文献   

15.
In this paper, we consider two versions of the Newton-type method for solving a nonlinear equations with nondifferentiable terms, which uses as iteration matrices, any matrix from B-differential of semismooth terms. Local and global convergence theorems for the generalized Newton and inexact generalized Newton method are proved. Linear convergence of the algorithms is obtained under very mild assumptions. The superlinear convergence holds under some conditions imposed on both terms of equation. Some numerical results indicate that both algorithms works quite well in practice.   相似文献   

16.
On the Newton Interior-Point Method for Nonlinear Programming Problems   总被引:2,自引:0,他引:2  
Interior-point methods have been developed largely for nonlinear programming problems. In this paper, we generalize the global Newton interior-point method introduced in Ref. 1 and we establish a global convergence theory for it, under the same assumptions as those stated in Ref. 1. The generalized algorithm gives the possibility of choosing different descent directions for a merit function so that difficulties due to small steplength for the perturbed Newton direction can be avoided. The particular choice of the perturbation enables us to interpret the generalized method as an inexact Newton method. Also, we suggest a more general criterion for backtracking, which is useful when the perturbed Newton system is not solved exactly. We include numerical experimentation on discrete optimal control problems.  相似文献   

17.
An augmented Lagrangian SQP method is discussed for a class of nonlinear optimal control problems in Banach spaces with constraints on the control. The convergence of the method is investigated by its equivalence with the generalized Newton method for the optimality system of the augmented optimal control problem. The method is shown to be quadratically convergent, if the optimality system of the standard non-augmented SQP method is strongly regular in the sense of Robinson. This result is applied to a test problem for the heat equation with Stefan-Boltzmann boundary condition. The numerical tests confirm the theoretical results.  相似文献   

18.
In this paper, we focus on solving a class of nonlinear complementarity problems with non-Lipschitzian functions. We first introduce a generalized class of smoothing functions for the plus function. By combining it with Robinson's normal equation, we reformulate the complementarity problem as a family of parameterized smoothing equations. Then, a smoothing Newton method combined with a new nonmonotone line search scheme is employed to compute a solution of the smoothing equations. The global and local superlinear convergence of the proposed method is proved under mild assumptions. Preliminary numerical results obtained applying the proposed approach to nonlinear complementarity problems arising in free boundary problems are reported. They show that the smoothing function and the nonmonotone line search scheme proposed in this paper are effective.  相似文献   

19.
本文给出新的NCP函数,这些函数是分段线性有理正则伪光滑的,且具有良好的性质.把这些NCP函数应用到解非线性优化问题的方法中.例如,把求解非线性约束优化问题的KKT点问题分别用QP-free方法,乘子法转化为解半光滑方程组或无约束优化问题.然后再考虑用非精确牛顿法或者拟牛顿法来解决该半光滑方程组或无约束优化问题.这个方法是可实现的,且具有全局收敛性.可以证明在一定假设条件下,该算法具有局部超线性收敛性.  相似文献   

20.
Many optimization problems can be reformulated as a system of equations. One may use the generalized Newton method or the smoothing Newton method to solve the reformulated equations so that a solution of the original problem can be found. Such methods have been powerful tools to solve many optimization problems in the literature. In this paper, we propose a Newton-type algorithm for solving a class of monotone affine variational inequality problems (AVIPs for short). In the proposed algorithm, the techniques based on both the generalized Newton method and the smoothing Newton method are used. In particular, we show that the algorithm can find an exact solution of the AVIP in a finite number of iterations under an assumption that the solution set of the AVIP is nonempty. Preliminary numerical results are reported.  相似文献   

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