共查询到20条相似文献,搜索用时 156 毫秒
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约束传播算法是求解约束满足问题的一种重要方法。调度问题是一种特殊的约束满足问题。本介绍了调度问题中的Edge-Finding和Energy-Reasoning两种分离约束传播算法,并对它们进行了比较,中最后给出了一种结合Energy-Reasoning的Edge-Finding改进算法。 相似文献
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赵天宇 《应用数学与计算数学学报》2002,16(1):29-34
本文给出了求解一类约束优化问题的一个Newton分裂算法,并证明了算法的局部平方收敛性,该算法与已有算法相比,具有计算量小的特点,因而特别适合于求解大规模问题,为进一步降低算法的计算复杂性,我们结合Broyden算法,给出了两类Broyden类分裂算法。 相似文献
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本文分别基于原始变分形式与对偶混合变分形式,对一类单边约束问题进行了数值求解,提出了求解离散对偶混合变分问题的Uzawa型算法,并用数值例子验证了算法的有效性. 相似文献
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概率约束问题的对偶切平面算法 总被引:1,自引:0,他引:1
概率约束问题的对偶切平面算法唐恒永(沈阳师范学院数学计算机系,沈阳110031)一、引言随机规划中的概率约束问题能应用于很多工程技术和经济问题。由于该问题具有难以处理的非线性的概率约束,所以求解起来比较困难。[1]给出了求解这类问题的一个综述,比较容... 相似文献
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求解约束极大极小问题的一种熵函数法 总被引:7,自引:0,他引:7
1引言熵函数法的原始思想源于Kreisselmeier和Steinhauser于1979年发表的文[1].由于使用该方法容易编制可以求解多类优化问题的通用软件,并在具有某种凸性的情况下都能求得满足工程精度要求的解,因而受到国内外工程技术人员的喜爱,进入八十年代以来,该方法被广泛地应用于结构优化和工程设计等领域[2-5].近年来,熵函数法在求解约束和无约束极大极小问题、线性规划以及半无限规划等问题的算法研究中,也取得了一些很好的成果[6-9]带有等式或不等式约束的极大极小问题是一类具有广泛代表性的… 相似文献
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郭飞 《应用数学与计算数学学报》1997,11(1):19-26
Wilson,Han和Powell提出的序列二次规划方法(简称SQP方法)是求解非线性规划问题的一个著名方法,这种方法每次迭代的搜索方向是通过求解一个二次规划子问题得到的,本文受[1]启发,得到二次规划子问题的一个近似解,进而给出了一类求解线性约束非线性规划问题的可行方向法,在约束集合满足正则性的条件下,证明了该算法对五种常用线性搜索方法具有全局收敛性。 相似文献
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针对均衡约束数学规划模型难以满足约束规范及难于求解的问题,基于Mond和Weir提出的标准非线性规划的对偶形式,利用其S稳定性,建立了均衡约束数学规划问题的一类广义Mond-Weir型对偶,从而为求解均衡约束优化问题提供了一种新的方法.在Hanson-Mond广义凸性条件下,利用次线性函数,分别提出了弱对偶性、强对偶性和严格逆对偶性定理,并给出了相应证明.该对偶化方法的推广为研究均衡约束数学规划问题的解提供了理论依据. 相似文献
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In this paper, we consider a kind of inverse model for the most uniform problem. This model has some practical background. It is shown that the model can be solved in polynomial time whenever an associated min-sum problem can be solved in polynomial time. 相似文献
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This paper studies the stability of the set containment problem. Given two non-empty sets in the Euclidean space which are
the solution sets of two systems of (possibly infinite) inequalities, the Farkas type results allow to decide whether one
of the two sets is contained or not in the other one (which constitutes the so-called containment problem). In those situations
where the data (i.e., the constraints) can be affected by some kind of perturbations, the problem consists of determining
whether the relative position of the two sets is preserved by sufficiently small perturbations or not. This paper deals with
this stability problem as a particular case of the maintaining of the relative position of the images of two set-valued mappings;
first for general set-valued mappings and second for solution sets mappings of convex and linear systems. Thus the results
in this paper could be useful in the postoptimal analysis of optimization problems with inclusion constraints.
相似文献
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The cycling operation is a special kind of conjugation that can be applied to elements in Artin’s braid groups, in order to reduce their length. It is a key ingredient of the usual solutions to the conjugacy problem in braid groups. In their seminal paper on braid-cryptography, Ko, Lee et al. proposed the cycling problem as a hard problem in braid groups that could be interesting for cryptography. In this paper we give a polynomial solution to that problem, mainly by showing that cycling is surjective, and using a result by Maffre which shows that pre-images under cycling can be computed fast. This result also holds in every Artin-Tits group of spherical type, endowed with the Artin Garside structure.On the other hand, the conjugacy search problem in braid groups is usually solved by computing some finite sets called (left) ultra summit sets (left-USSs), using left normal forms of braids. But one can equally use right normal forms and compute right-USSs. Hard instances of the conjugacy search problem correspond to elements having big (left and right) USSs. One may think that even if some element has a big left-USS, it could possibly have a small right-USS. We show that this is not the case in the important particular case of rigid braids. More precisely, we show that the left-USS and the right-USS of a given rigid braid determine isomorphic graphs, with the arrows reversed, the isomorphism being defined using iterated cycling. We conjecture that the same is true for every element, not necessarily rigid, in braid groups and Artin-Tits groups of spherical type. 相似文献
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We introduce the generalized elementary shortest path problem (GESPP) where in addition to the features of the shortest path problem, nodes belong to predefined non-disjoint clusters. Each cluster is associated to a profit to the cost function, obtained if at least one element in the cluster appears in the path. Several applications can be considered as school bus routing, pricing problems, or telecommunication network design. Thus, depending on the case, clusters could be interpreted as groups of nodes with linking features as, for example, being easily reachable from each other, or some kind of coverage guarantee. We compare the GESPP to similar problems in the literature and we propose a two-phase heuristic algorithm for graphs including negative cycles. Tests on random instances with up to 100 nodes show an average gap of 0.3% to the best known solutions computed in 2.8s in average. 相似文献
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设施选址问题是组合优化中重要问题之一。动态设施选址问题是传统设施选址问题的推广,其中度量空间中设施的开设费用和顾客的需求均随着时间的变化而变化。更多地,经典设施选址问题假设所有的顾客都需要被服务。在这个模型假设下,所有的顾客都需要服务。但事实上,有时为服务距离较远的顾客,需要单独开设设施,导致了资源的浪费。因此,在模型设置中,可以允许一些固定数目的顾客不被服务 (带异常点的设施选址问题),此外也可以通过支付一些顾客的惩罚费用以达到不服务的目的 (带惩罚的设施选址问题)。本文将综合以上两种鲁棒设置考虑同时带有异常点和惩罚的动态设施选址问题,通过原始-对偶框架得到近似比为3的近似算法。 相似文献
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研究含参数$l$非方矩阵对广义特征值极小扰动问题所导出的一类复乘积流形约束矩阵最小二乘问题.与已有工作不同,本文直接针对复问题模型,结合复乘积流形的几何性质和欧式空间上的改进Fletcher-Reeves共轭梯度法,设计一类适用于问题模型的黎曼非线性共轭梯度求解算法,并给出全局收敛性分析.数值实验和数值比较表明该算法比参数$l=1$的已有算法收敛速度更快,与参数$l=n$的已有算法能得到相同精度的解.与部分其它流形优化相比与已有的黎曼Dai非线性共轭梯度法具有相当的迭代效率,与黎曼二阶算法相比单步迭代成本较低、总体迭代时间较少,与部分非流形优化算法相比在迭代效率上有明显优势. 相似文献
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The matrix with centrosymmetric structure is an important kind of structured matrices with many applications in various physics and engineering problems.The eigenvalue problem for a centrosymmetric matrix can be reduced to the other eigenvalue problems of lower order.We introduce the centrosymmetric structure to the tensor field and focus on the spectral radius of this particular tensor.Then we show that properties of centrosymmetric matrices hold true for tensors situation. 相似文献
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航空器供油问题是一类非线性组合优化问题,其目标函数为分式形式,该问题目前不存在多项式时间算法,也未被证明是NP完全问题。一般可以用置换来刻画n架飞机的一个供油顺序。该问题中有一类实例被称为“完全逆序类”,“完全逆序类”用动态规划算法求解计算时间为O(n2n),具有指数时间复杂度。本文通过对该“完全逆序类”问题做进一步分析,发现在“完全逆序类”中也存在着多项式时间可解的情况。定理1研究一类一次可解的情况,若问题满足定理1的条件,则求解一次即可找到其最优解;定理2研究一类多项式时间可解的情况,当问题满足定理2的条件时,其最优解可在多项式时间内获得。 相似文献
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抽象经济均衡问题解的存在性及其算法 总被引:3,自引:0,他引:3
本文首先研究一类新的向量均衡问题,利用截口定理与KKM定理两种不同的工具证明此类均衡问题解的存在性,接着,把这类向量均衡问题推广到更为一般的情形,随后讨论了具有上下界的均衡问题,它是由Isac,Sehgal和Singh于1999年提出的一个公开问题,本文在一定条件下获得了一个新的解的存在性定理,并构造了一个迭代算法,讨论了算法的收敛性。 相似文献