数值最优化的弧搜索方法

非线性最优化算法主要包括两个步骤:一是利用目标函数和约束函数的导数或相关信息来确定搜索方向,二是利用一维搜索和信赖域方法来确定沿搜索方向步长.一维直线搜索在各种教科书及参考文献中被广泛地讨论过,而另一种搜索方法弧搜索方法,在某些情况下更有效却鲜为人知.本文讨论弧搜索方法的一些细节及在各种最优化问题中的应用,并指出弧搜索技术比直线搜索对某些问题更具优越性.     

解无约束优化问题的一个新的带线搜索的信赖域算法

在传统信赖域方法的基础上, 提出了求解无约束最优化问题的一个新的带线搜索的信赖域算法. 该算法采用大步长 Armijo 线搜索技术获得迭代步长, 克服了每次迭代求解信赖域子问题时计算量较大的缺点, 因而适用于求解大型的优化问题. 在适当的条件下, 我们证明了算法的全局收敛性. 数值实验结果表明本文所提出的算法是有效的.     

一类带线搜索的非单调信赖域新算法

结合非单调信赖域方法,和非单调线搜索技术,提出了一种新的无约束优化算法.信赖域方法的每一步采用线搜索,使得迭代每一步都充分下降加快了迭代速度.在一定条件下,证明了算法具有全局收敛性和局部超线性.收敛速度.数值试验表明算法是十分有效的.     

一类带线搜索的自适应信赖域算法

本文对无约束优化问题提出了一类带线搜索的自适应信赖域算法,新算法在试验步失败时不重解子问题,而是采用线搜索,从而减少了计算量,不同于一般的带线搜索的信赖域算法,新算法根据实际下降量与预估下降量的比值按照变化的速率对信赖域半径进行调整.文中在一定的条件下证明了算法的收敛性,并且给出了相应的数值实验结果.     

一个解界约束非线性方程组的无导数回溯线搜索仿射内点信赖域方法（英文）

文章给出了一个求解界约束非线性方程组的无导数回溯线搜索仿射内点信赖域方法.该方法利用非线性方程组的特点,对方程组中每一个函数建立插值模型.通过利用信赖域模型和回溯先搜索技术的结合,利用插值信赖域子问题子问题求解搜索方向,并利用回溯先搜索技术保证可行性.在合理的假设条件下,证明了算法的全局和快速局部收敛性.并且,通过数值实验表明该种无导数算法对求解界约束非线性方程组问题是有效的.     

一类新的非单调信赖域算法

提出了一类带线性搜索的非单调信赖域算法.算法将非单调Armijo线性搜索技术与信赖域方法相结合,使算法不需重解子问题.而且由于采用了MBFGS校正公式,使矩阵Bk能较好地逼近目标函数的Hesse矩阵并保持正定传递.在较弱的条件下,证明了算法的全局收敛性.数值结果表明算法是有效的.     

一种非单调自适应不定折线信赖域算法

提出了一种非单调自适应不定折线信赖域算法,当B_k不正定时,运用Bunch-Parlett分解产生搜索路径来确定下降方向.与一般的非单调信赖域算法相比,新算法根据实际下降量与预估计下降量的比值按照变化的速率对信赖域半径进行调整,在研究方法上具有一定的创新.     

一类带非单调线搜索的非单调信赖域新算法

文章结合非单调信赖域方法和非单调线搜索技术提出了一类新的无约束优化算法.与传统的非单调信赖与算法相比,此算法在每步都采用非单调Wolfe线搜索得到下一个迭代点,信赖域半径由子问题的近似解和线搜索的步长调节,这样得到的新算法不仅不需重解子问题,而且在每步迭代保证目标函数的近似海赛矩阵的正定性,在一定条件下证明了算法具有全局收敛性和Q-二次收敛性.数值试验表明算法是十分有效的.     

一个新的MBFGS信赖域算法

本文研究了无约束最优化问题.利用MBFGS信赖域算法的基本思想,通过对BFGS校正公式的改进,并结合线搜索技术,提出了一种新的MBFGS信赖域算法,拓宽了信赖域算法的适用范围,并在一定条件下证明了该算法的全局收敛性和超线性收敛性.     

非线性等式约束优化问题的仿射信赖域方法

提出非线性等式和有界约束优化问题的结合非单调技术的仿射信赖域方法. 结合信赖域方法和内点回代线搜索技术, 每一步迭代转到由一般信赖域子问题产生的回代步中且满足严格内点可行条件. 在合理的假设条件下, 证明了算法的整体收敛性和局部超线性收敛速率. 最后, 数值结果表明了所提供的算法具有有效性.     

A nonmonotone trust region method with new inexact line search for unconstrained optimization

In this paper, a new nonmonotone inexact line search rule is proposed and applied to the trust region method for unconstrained optimization problems. In our line search rule, the current nonmonotone term is a convex combination of the previous nonmonotone term and the current objective function value, instead of the current objective function value . We can obtain a larger stepsize in each line search procedure and possess nonmonotonicity when incorporating the nonmonotone term into the trust region method. Unlike the traditional trust region method, the algorithm avoids resolving the subproblem if a trial step is not accepted. Under suitable conditions, global convergence is established. Numerical results show that the new method is effective for solving unconstrained optimization problems.     

Combining trust region and linesearch algorithm for equality constrained optimization

In this paper, a combining trust region and line search algorithm for equality constrained optimization is proposed. At each iteration, we only need to solve the trust region subproblem once, when the trust region trial step can not be accepted, we switch to line search to obtain the next iteration. Hence, the difficulty of repeated solving trust region subproblem in an iterate is avoided. In order to allow the direction of negative curvature, we add second correction step in trust region step and employ nommonotone technique in line search. The global convergence and local superlinearly rate are established under certain assumptions. Some numerical examples are given to illustrate the efficiency of the proposed algorithm.     

一类拟牛顿非单调信赖域算法及其收敛性

本文提出了一类求解无约束最优化问题的非单调信赖域算法.将非单调Wolfe线搜索技术与信赖域算法相结合,使得新算-法不仅不需重解子问题,而且在每步迭代都满足拟牛顿方程同时保证目标函数的近似Hasse阵Bk的正定性.在适当的条件下,证明了此算法的全局收敛性.数值结果表明该算法的有效性.     

A Line Search and Trust Region Algorithm with Trust Region Radius Converging to Zero

In this paper, we present a new line search and trust region algorithm for unconstrained optimization problem with the trust region radius converging to zero. The new trust region algorithm performs a backtracking line search from the failed, point instead of resolving the subproblem when the trial step results in an increase in the objective function. We show that the algorithm preserves the convergence properties of the traditional trust region algorithms. Numerical results are also given.     

一个新的BFGS信赖域算法

本文对于无约束最优化问题提出了一个新的BFGS信赖域算法.利用BFGS方法和信赖域方法,提出了改进的BFGS信赖域方法.推广了文献[3,5]中的两种算法,得到一个新的BFGS信赖域算法,在适当条件下证明了算法的全局收敛性.     

An improved trust region algorithm for nonlinear equations

In this paper, we present a new trust region algorithm for the system of singular nonlinear equations with the regularized trust region subproblem. The new algorithm preserves the global convergence of the traditional trust region algorithm, and has the quadratic convergence under some suitable conditions. Finally, some numerical results are given.     

On memory gradient method with trust region for unconstrained optimization

In this paper we present a new memory gradient method with trust region for unconstrained optimization problems. The method combines line search method and trust region method to generate new iterative points at each iteration and therefore has both advantages of line search method and trust region method. It sufficiently uses the previous multi-step iterative information at each iteration and avoids the storage and computation of matrices associated with the Hessian of objective functions, so that it is suitable to solve large scale optimization problems. We also design an implementable version of this method and analyze its global convergence under weak conditions. This idea enables us to design some quick convergent, effective, and robust algorithms since it uses more information from previous iterative steps. Numerical experiments show that the new method is effective, stable and robust in practical computation, compared with other similar methods.     

A new nonmonotone adaptive trust region method based on simple quadratic models

Based on simple quadratic models of the trust region subproblem, we combine the trust region method with the nonmonotone and adaptive techniques to propose a new nonmonotone adaptive trust region algorithm for unconstrained optimization. Unlike traditional trust region method, our trust region subproblem is very simple by using a new scale approximation of the minimizing function??s Hessian. The new method needs less memory capacitance and computational complexity. The convergence results of the method are proved under certain conditions. Numerical results show that the new method is effective and attractive for large scale unconstrained problems.