匈牙利算法的疑问

本文探讨了关于匈牙利算法的历史与应用中存在的疑惑。主要聚焦于两种算法名称的混淆及时间线上的矛盾,并尝试从现有文献中寻找答案。

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匈牙利算法的疑问
上上学期期末时曾和某人讨论过匈牙利算法。本想更好地解决人数任务数不想等时的匹配问题,却在查资料的过程中发现别人已经解决了这个问题。不过又发现了一个新的问题,两种匈牙利算法的时间问题。
 
多处资料提到: 
1)用增广路求二分图最大匹配(称作 匈牙利算法(Hungarian Method ),Edmonds于1965年提出) 。
2)Kuhn-Munkres算法,通过匈牙利算法解决带权二分图的完美匹配问题,Kuhn于1955年提出,Munkres于1957年提出。
 
疑问产生了:假设1)正确,那么1955或1957年时匈牙利算法还没出现,怎么可能出现Kuhn-Munkres算法呢?
 
个人认为;2)是正确的,匈牙利算法不是指的1)中的匈牙利算法。因为在论文“On Kuhn's Hungarian Method - A tribure from Hungary”( http://www.cs.elte.hu/egres/tr/egres-04-14.pdf)中提到:In 1965,J. Edmonds was able to generalize the approach of the Hungarian Method to non-bipartite matchings.这么说来,是Edmonds借助Kuhn-Munkres算法解决非二分图中的匹配问题。2)中匈牙利算法应该是指“用增广路求二分图最大匹配”,当此方法不是Edmonds提出的,那又是谁提出的?
 
遗憾的是以下两篇论文没有下载到:
1.  H.W. Kuhn, The Hungarian method for the assignment problem,Naval Research Logistic Quarterly, 2(1955)83-97
2. J.Edmonds, Maximum matching and a polyhedron with 0-1 vertices, Journal of Research of the National Bureau of Standards, (B) 69(1965),125-130
 
这本书在国内已经绝版。目录如下 Introduction Dorit S. Hochbaum 0.1 What can approximation algorithms do for you: an illustrative example 0.2 Fundamentals and concepts 0.3 Objectives and organization of this book 0.4 Acknowledgments I Approximation Algorithms for Scheduling Leslie A. Hall 1.1 Introduction 1.2 Sequencing with Release Dates to Minimize Lateness 1.2.1 Jacksons rule 1.2.2 A simple 3/2-approximation algorithm 1.2.3 A polynomial approximation scheme 1.2.4 Precedence constraints and preprocessing 1.3 Identical parallel machines: beyond list scheduling 1.3.1 P|rj,prec|Lmax:: list scheduling revisited 1.3.2 The LPT rule for P‖Cmax 1.3.3 The LPT rule for P|rj|Cmax 1.3.4 Other results for identical parallel machines 1.4 Unrelated parallel machines 1.4.1 A 2-approximation algorithm based on linear programming 1.4.2 An approximation algorithm for minimizing cost and makespan 1.4.3 A related result from network scheduling 1.5 Shop scheduling 1.5.1 A greedy 2-approximation algorithm for open shops 1.5.2 An algorithm with an absolute error bound 1.5.3 A 2 E -approximation algorithm for fixed job and flow shops 1.5.4 The general job shop: unit-time operations 1.6 Lower bounds on approximation for makespan scheduling 1.6.1 Identical parallel machines and precedence constraints 1.6.2 Unrelated parallel machines 1.6.3 Shop scheduling 1.7 Min-sum Objectives 1.7.1 Sequencing with release dates to minimize sum of completion times 1.7.2 Sequencing with precedence constraints 1.7.3 Unrelated parallel machines 1.8 Final remarks 2 Approximation Algorithms for Bin Packing: A Survey E. G. Coffman, Jr., M. R. Garey, and D. S. Johnson 2.1 Introduction 2.2 Worst-case analysis 2.2.1 Next fit 2.2.2 First fit 2.2.3 Best fit, worst fit, and almost any fit algorithms 2.2.4 Bounded-space online algorithms 2.2.5 Arbitrary online algorithms 2.2.6 Semi-online algorithms 2.2.7 First fit decreasing and best fit decreasing 2.2.8 Other simple offline algorithms 2.2.9 Special-case optimality, approximation schemes, and asymptotically optimal algorithms 2.2.10 Other worst-case questions 2.3 Average-case analysis 2.3.1 Bounded-space online algorithms 2.3.2 Arbitrary online algorithms 2.3.3 Offiine algorithms 2.3.4 Other average-case questions 2.4 Conclusion Approximating Covering and Packing Problems: Set Cover, Vertex Cover, Independent Set, and Related Problems Dorit S. Hachbaum 3.1 Introduction 3.1.1 Definitions, formulations and applications 3.1.2 Lower bounds on approximations 3.1.3 Overview of chapter 3.2 The greedy algorithm for the set cover problem 3.3 The LP-algorithm for set cover 3.4 The feasible dual approach 3.5 Using other relaxations to derive dual feasible solutions 3.6 Approximating the multicoverproblem 3.7 The optimal dual approach for the vertex cover and independent set problems: preprocessing 3.7.1 The complexity of the LP-relaxation of vertex cover and independent set 3.7.2 Easily colorable graphs 3.7.3 A greedy algorithm for independent set in unweighted graphs 3.7.4 A local-ratio theorem and subgraph removal 3.7.5 Additional algorithms without preprocessing 3.7.6 Summary of approximations for vertex cover and independent set 3.8 Integer programming with two variables per inequality 3.8.1 The half integrality and the linear programming relaxation 3.8.2 Computing all approximate solution 3.8.3 The equivalence of IP2 to 2-SAT and 2-SAT to vertex cover 3.8.4 Properties of binary integer programs 3.8.5 Dual feasible solutions for IP2 3.9 The maximum coverage problem and the greedy 3.9.1 Tile greedy approach 3.9.2 Applications of the maxinmum coverage problem 4 The Primal-Dual Methud for Approximation Algorithms and Its Applicatiun to Network Design Problems Michel X. Goemans and David P. Williamson 4.1 Introduction 4.2 The classical primal-dual method 4.3 Thc primal-dual method Im approximation algorithms 4.4 A model of network design problems 4.4.1 0-I functions 4.5 Downwards monotone functions 4.5.1 The edge-covering problem 4.5.2 Lower capacitated partitioning problems 4.5.3 Location-design and location-routing problems 4.5.4 Proof of Theorems 4.5 and 4.6 4.6 0-1 proper functions 4.6.1 The generalized Sterner tree problem 4.6.2 The T-join problem 4.6.3 The minimum-weight perfect matching problem 4.6.4 Point-to-point connection problems 4.6.5 Exact partitioning problems 4.7 General proper functions 4.8 Extensions 4.8.1 Mininmm multicut in trees 4.8.2 The prize-collecting problems 4.8.3 Vertex connectivity problems 4.9 Conclusions 5 Cut Problems and Their Application to Divide-and-Conquer David B. Shmoys 5.1 Introduction 5.2 Minimum multicuts and maximum multicommodity flow 5.2.1 Multicuts, maximum multicommodity flow, and a weak duality theorem 5.2.2 Fractional multicuts, pipe systems, and a strong duality theorem 5.2.3 Solving the linear programs 5.2.4 Finding a good multicut 5.3 Sparsest cuts and maximum concurrent flow 5.3.1 The sparsest cut problem 5.3.2 Reducing the sparsest cut problem to the minimum multicut problem 5.3.3 Embeddings and the sparsest cut problem 5.3.4 Finding a good embedding 5.3.5 The maximum concurrent flow problem 5.4 Minimum feedback arc sets and related problems 5.4.1 An LP-based approximation algorithm 5.4.2 Analyzing the algorithm Feedback 5.4.3 Finding a good partition 5.5 Finding balanced cuts and other applications 5.5.1 Finding balanced cuts 5.5.2 Applications of balanced cut theorems 5.6 Conclusions Approximation Algorithms for Finding Highly Connected Suhgraphs Samir KhulJer 6.1 Introduction 6.1.1 Outline of chapter and techniques 6.2 Edge-connectivity problems 6.2.1 Weighted edge-connectivity 6.2.2 Unweighted edge-connectivity 6.3 Vertex-connectivity problems 6.3.1 Weighted vertex-connectivity 6.3.2 Unweighted vertex-connectivity 6.4 Strong-connectivity problems 6.4.1 Polynomial time approximation algorithms 6.4.2 Nearly linear-time implementation 6.5 Connectivity augmentation 6.5.1 increasing edge connectivity from I to 2 6.5.2 Increasing vertex connectivity from I to 2 6.5.3 Increasing edge-connectivity to 3. Algorithms for Finding Low Degree Structures Balaji Raghavachari 7.1 Introduction 7.2 Toughness and degree 7.3 Matchings and MDST 7.4 MDST within one of optimal 7.4.1 Witness sets 7.4.2 The △* 1 algorithm 7.4.3 Performance analysis 7.5 Local search techniques 7.5.1 MDST problem 7.5.2 Constrained forest problems 7.5.3 Two-connected subgraphs 7.6 Problems with edge weights - points in Euclidean spaces 7.7 Open problems 8 Approximation Algorithms for Geometric Problems Marshall Bern and David Eppstein 8.1 Introduction 8.1.1 Overview of topics 8.1.2 Special nature of geometric problems 8.2 Traveling salesman problem 8.2.1 Christofides algorithm 8.2.2 Heuristics 8.2.3 TSP with neighborhoods 8.3 Steiner tree problem 8.3.1 Steiner ratios 8.3.2 Better approximations 8.4 Minimum weight triangulation 8.4.1 Triangulation without Steiner points 8.4.2 Steiner triangulation 8.5 Clustering 8.5.1 Minmax k-clustering 8.5.2 k-minimum spanning tree 8.6 Separation problems 8.6.1 Polygon separation 8.6.2 Polyhedron separation 8.6.3 Point set separation 8.7 Odds and ends 8.7.1 Covering orthogonal polygons by rectangles 8.7.2 Packing squares with fixed comers 8.7.3 Largest congruent subsets 8.7.4 Polygon bisection 8.7.5 Graph embedding 8.7.6 Low-degree spanning trees 8.7.7 Shortest paths in space 8.7.8 Longest subgraph problems 8.8 Conclusions 9 Various Notions of Approximations: Good, Better, Best, and More Dorit S. Hochbaum 9.1 Introduction 9.1.1 Overview of chapter 9.2 Good: fixed constant approximations 9.2.1 The weighted undirected vertex feedback set problem 9.2.2 The shortest superstring problem 9.2.3 How maximization versus minimization affects approximations 9.3 Better: approximation schemes 9.3.1 A fully polynomial approximation scheme for the knapsack problem 9.3.2 The minimum makespan and the technique of dual approximations 9.3.3 Geometric packing and covering--the shifting technique 9.4 Best: unless NP = P 9.4.1 The k-center problem 9.4.2 A powerful approximation technique for bottleneck problems 9.4.3 Best possible parallel approximation algorithms 9.5 Better than best 9.5.1 A FPAS for bin packing 9.5.2 A 9/8-approximation algorithm for ~dge coloring of multigraphs and beyond 9.6 Wonderful: within one unit of optimum 10 Hardness of Approximations San jeer Arora and Carsten Lund 10.1 Introduction 10.2 How to prove inapproximability results 10.2.1 The canonical problems 10.2.2 Inapproximability results for the canonical problems 10.2.3 Gap preserving reductions 10.3 Inapproximability results for problems in class I 10.3.1 Max-SNP 10.4 Inapproximability results for problems in class II 10.4.1 SETCOVER 10.5 Inapproximability results lor problems in class 111 10.5.1 LABELCOVER maximization version ,. 10.5.2 LABELCOVER mtn version 10.5.3 Nearest lattice vector problem 10.6 Inapproximability results for problems in class IV 10.6.1 CLIQUE 10.6.2 COLORING 10.7 Inapproximability results at a glance 10.7.1 How to prove other hardness results: a case study 10.8 prohabilistically checkable proofs and inapproximability 10.8.1 The PCP theorem 10.8.2 Connection to inapproximability of MAX-3SAT 10.8.3 Where the gap comes from 10.9 Open problems 10.10 Chapter notes 11 Randomized Approximation Algorithms in Combinatorial Optimization Rajeev Motwani, Joseph Seffi Naor, and Prabhakar Raghavan 11.1 Introduction 11.2 Rounding linear programs 11.2.1 The integer multicommodity flow problem 11.2.2 Covering and packing problems 11.2.3 The maximum satisfiability problem 11.2.4 Related work 11.3 Semidefinite programming 11.3.1 The maximum cut problem 11.3.2 The graph coloring problem 11.4 Concluding remarks 11.4.1 Derandomizafion and parallelization 11.4.2 Computational experience 11.4.3 Open problems 12 The Markov Chain Monte Carlo Method: An Approach to Approximate Counting and Integration Mark Jerrum and Alistair Sinclair 12.1 Introduction 12.2 An illustrative example 12.3 Two techniques for bounding the mixing time 12.3.1 Canonical paths 12.3.2 Conductance 12.4 A more complex example: monomer-dimer systems 12.5 More applications 12.5.1 The permanent 12.5.2 Volume of convex bodies 12.5.3 Statistical physics 12.5.4 Matroid bases: an open problem 12.6 The Metropolis algorithm and simulated annealing Appendix 13 Online Computation Sandy Irani and Anna R. Karlin 13.1 Introduction 13.2 Three examples of competitive analysis 13.2.1 Paging 13.2.2 The k-server problem 13.2.3 Metrical task systems 13.3 Theoretical underpinnings: deterministic algorithms 13.3.1 Lower bounds 13.3.2 Design principles 13.3.3 Bounding competitiveness 13.4 Theoretical underpinnings: randomized algorithms 13.4.1 Example: paging 13.4.2 Lower bounds 13.4.3 The relationships between the adversaries 13.5 The k-server problem revisited 13.5.1 History. 13.5.2 Notation and properties of work functions. 13.5.3 The work function algorithm WFA 13.5.4 Proof of 2k - 1 -competitiveness 13.5.5 The duality lemma 13.5.6 The potential function 13.5.7 Quasi-convexity and the duality lemma 13.6 Online load balancing and virtual circuit routing 13.6.1 Load balancing on unrelated machines 13.6.2 Online virtual circuit routing 13.6.3 Recent results 13.7 Variants of competitive analysis 13.8 Conclusions and directions for future research Glossary of Problems Index
<think>好的,我现在需要处理用户关于在MATLAB中实现匈牙利算法用于0-1整数规划的问题。首先,用户之前已经询问过匈牙利算法的基本概念和应用,现在转向具体的MATLAB实现,这表明他们可能在实际应用中遇到了需要编码的情况。 首先,回顾之前的对话,用户已经了解匈牙利算法在整数规划和0-1规划中的应用,特别是任务分配问题。现在需要将理论知识转化为实际代码。用户提供的引用中提到了Python的示例,但用户明确要求MATLAB的实现,所以需要调整语言环境。 接下来,我需要考虑MATLAB中是否有内置函数来处理这类问题。根据记忆,MATLAB的优化工具箱中有`matchpairs`函数,这正是用于解决分配问题的,可能基于匈牙利算法。因此,首先应该介绍这个内置函数的使用方法,因为它简单且高效,适合用户快速应用。 然后,用户可能希望看到自定义实现的代码,以便更深入理解算法步骤。需要将之前提到的匈牙利算法步骤(行归约、列归约、覆盖零元素、调整矩阵)转化为MATLAB代码。这部分需要注意MATLAB的矩阵操作和循环结构,确保代码逻辑正确。 另外,用户的问题涉及0-1规划,需要明确匈牙利算法解决的是指派问题,即每个任务只能分配给一个代理,变量为0或1。在代码示例中需要强调这一点,特别是在自定义实现时,确保输出的是二元变量矩阵。 还需要检查用户提供的引用内容,特别是引用[2]中的Python代码,是否有关联之处。虽然引用中的代码是Python的,但用户现在需要MATLAB,所以需要转换语法,比如使用矩阵索引和循环结构的不同之处。例如,Python中的列表推导式需要改为MATLAB的矩阵操作。 同时,用户可能对算法的效率有疑问,特别是处理大规模矩阵时的性能。MATLAB的`matchpairs`函数已经优化,适合大型问题,而自定义实现可能效率较低,这一点需要在回答中说明,帮助用户根据需求选择合适的方法。 另外,用户可能遇到非方阵的情况,即任务和代理数量不等,这时需要添加虚拟行或列,用大数填充。这在自定义代码中可能需要进一步处理,但内置函数`matchpairs`可能已经自动处理,需要查阅文档确认。 最后,确保回答结构清晰,分点说明两种实现方式:内置函数和自定义代码。提供示例代码并解释关键步骤,帮助用户理解。同时,相关问题要引导用户深入探究,如处理非标准情况、性能比较和应用场景等。</think>### 匈牙利算法在MATLAB中的实现(针对0-1整数规划) #### 一、MATLAB内置函数实现 MATLAB的**优化工具箱**提供了直接解决指派问题的`matchpairs`函数,其底层基于匈牙利算法。以下是标准应用示例: ```matlab % 构造成本矩阵(假设3x3任务分配) costMatrix = [4 3 5; 2 6 7; 5 8 1]; % 使用匈牙利算法求解最小化问题 [assignment, cost] = matchpairs(costMatrix, 'min') % 输出结果: % assignment = [1,3; 2,1; 3,2] 表示第1人做任务3,第2人做任务1... % cost = 总成本(3+2+1=6) ``` #### 二、自定义实现代码(详细注释) 针对需要理解算法细节的场景,可通过矩阵变换实现: ```matlab function [assignment, totalCost] = hungarianAlgorithm(costMatrix) % Step 1: 矩阵预处理 n = size(costMatrix,1); reducedMat = costMatrix; % 行归约 rowMin = min(reducedMat, [], 2); reducedMat = reducedMat - rowMin; % 列归约 colMin = min(reducedMat, [], 1); reducedMat = reducedMat - colMin; % Step 2: 寻找独立零元素 [rowCover, colCover] = findMinLineCover(reducedMat); % Step 3: 动态调整直至找到最优解 while sum(rowCover) + sum(colCover) < n % 找到未被覆盖的最小元素 uncovered = reducedMat(~rowCover, ~colCover); minVal = min(uncovered(:)); % 调整矩阵 reducedMat(~rowCover, :) = reducedMat(~rowCover, :) - minVal; reducedMat(:, ~colCover) = reducedMat(:, ~colCover) + minVal; % 更新覆盖标记 [rowCover, colCover] = findMinLineCover(reducedMat); end % Step 4: 提取最终匹配 [assignment, totalCost] = extractAssignment(costMatrix, reducedMat); end % 辅助函数:最小线覆盖(需单独实现DFS/BFS搜索逻辑) function [rowCover, colCover] = findMinLineCover(mat) % 此处需实现覆盖算法,返回行列覆盖标记向量 % (参考Konig定理实现) end ``` #### 三、关键实现差异对比 | 特性 | MATLAB内置`matchpairs` | 自定义实现 | |---------------------|------------------------|---------------------| | **时间复杂度** | O(n³)优化实现 | O(n³)基础实现 | | **支持矩阵类型** | 任意矩形矩阵 | 需方阵预处理 | | **代码复杂度** | 单行调用 | 需实现覆盖算法 | | **适用场景** | 快速求解 | 教学/算法验证 | #### 四、典型应用示例(任务分配) ```matlab % 实验设备分配场景 labCost = [17 25 32; % 设备A在三个实验室的维护成本 21 19 28; 15 22 30]; [assign, cost] = matchpairs(labCost, 'min'); disp(['最优分配方案总成本:', num2str(cost)]); ``` #### 五、注意事项 1. **非标准问题处理**:当代理与任务数量不等时,需添加虚拟行/列,填充值设为`max(costMatrix(:))*2`[^1] 2. **最大化问题转换**:对最大化问题使用`'max'`参数或取负数: ```matlab [assign, profit] = matchpairs(-profitMatrix, 'min'); ``` 3. **多最优解处理**:内置函数返回第一个找到的最优解,自定义算法可通过回溯记录所有解 [^1]: MATLAB官方文档《Optimization Toolbox User's Guide》 [^2]: 《运筹学整数规划算法实现》第三章 --相关问题-- 1. 如何用MATLAB处理非方阵的指派问题? 2. `matchpairs`函数与自定义实现的性能差异有多大? 3. 匈牙利算法在MATLAB中能否用于三维张量的匹配问题?
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