当前课程知识点:计算几何 > 05. Delaunay Triangulation > B. Delaunay Triangulation > 05-B-02. Triangulation
那么这个dual graph
跟我们的主题三角剖分
有什么联系呢
联系就在于
由此得到的dual graph
一般而言
本身就是一个triangulation
为什么这么讲呢
回忆一下
在Voronoi图的那一章我们介绍过
Voronoi图有这么样一个性质
如果所有的顶点都是在一般的位置
准确地讲就是没有四点共圆的
那种特殊情况出现的话
那么每一个vertex的度数
都恰好是3
也就是说每一个vertex
都是恰好和三条边相关联
反过来呢
我们也可以认为
与同一个vertex
相关联的那三条边
比如说它 它和它
就会围成一个三角形
这个三角形对应于
原来的一个vertex
这里的每一个vertex
都对应于一个三角形
反之亦然
这就说明在这个dual graph中的
每一个face
都是由三条边围成的三角形
所以整体的是三角剖分
是名副其实的
当然刚才我们说了是
所有的点都是在一般性的位置
没有刚才说的那种奇异的情况
实际上在有奇异的情况下
我们同样可以略做修补
使它依然是一个三角剖分
那么这部分话题
我们限制时间的关系就不再介绍
大家可以去看相应的参考书
比如说在CGAA那本教材中
对这个花了相当多的篇幅进行讨论
-Before we start
--html
-Evaluation
--html
-Online Judge
--html
-Lecture notes
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-Discussion
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-A. History of This Course
--00-A. History of This Course
-B. What's Computational Geometry
--00-B. What's Computational Geometry
-B. What's Computational Geometry--作业
-C. How to Learn CG Better
--00-C. How to Learn CG Better
-C. How to Learn CG Better--作业
-D. Why English
-A. Convexity
-A. Convexity--作业
-B. Extreme Points
-B. Extreme Points--作业
-C. Extreme Edges
-C. Extreme Edges--作业
-D. Incremental Construction
--01-D-01. Decrease and Conquer
--01-D-02. In-Convex-Polygon Test
--01-D-03. Why Not Binary Search
-D. Incremental Construction--作业
-E. Jarvis March
--01-E-06. Lowest-Then-Leftmost
-E. Jarvis March--作业
-F. Lower Bound
--01-F-02. CAO Chong's Methodology
-F. Lower Bound--作业
-G. Graham Scan: Algorithm
-G. Graham Scan: Algorithm--作业
-H. Graham Scan: Example
-H. Graham Scan: Example--作业
-I. Graham Scan: Correctness
-I. Graham Scan: Correctness--作业
-J. Graham Scan: Analysis
-J. Graham Scan: Analysis--作业
-K. Divide-And-Conquer (1)
-K. Divide-And-Conquer (1)--作业
-L. Divide-And-Conquer (2)
--01-L-03. Topmost + Bottommost ?
--01-L-07. More Considerations
-L. Divide-And-Conquer (2)--作业
-M. Wrap-Up
-0. Introduction
-0. Introduction--作业
-A. Preliminary
-A. Preliminary--作业
-B. Interval Intersection Detection
-B. Interval Intersection Detection--作业
-C. Segment Intersection Reporting
-C. Segment Intersection Reporting--作业
-D. BO Algorithm: Strategy
--02-D-01. Proximity & Separability
--02-D-02. Comparability & Ordering
-D. BO Algorithm: Strategy--作业
-E. BO Algorithm: Implementation
--02-E-03. Events & Operations
-E. BO Algorithm: Implementation--作业
-F. BO Algorithm: Analysis
--02-F-04. Complexity of Event Queue
--02-F-05. Complexity of Status Structure
-F. BO Algorithm: Analysis--作业
-G. Convex Polygon Intersection Detection
--02-G-01. Problem Specification
--02-G-02. Monotone Partitioning
--02-G-04. Decrease-And-Conquer
-G. Convex Polygon Intersection Detection--作业
-H. Edge Chasing
--02-H-01. Eliminating Sickles
-H. Edge Chasing--作业
-I. Plane Sweeping
-I. Plane Sweeping--作业
-J. Halfplane Intersection Construction
-J. Halfplane Intersection Construction--作业
-0. Methodology
-0. Methodology--作业
-A. Art Gallery Problem
--03-A-02. Lower & Upper Bounds
--03-A-04. Approximation & Classification
-A. Art Gallery Problem--作业
-B. Art Gallery Theorem
--03-B-01. Necessity of floor(n/3)
--03-B-02. Sufficiency by Fan Decomposition
-B. Art Gallery Theorem--作业
-C. Fisk's Proof
--03-C-04. Pigeon-Hole Principle
-C. Fisk's Proof--作业
-D. Orthogonal Polygons
--03-D-01. Necessity of floor(n/4)
--03-D-02. Sufficiency by Convex Quadrilateralization
-D. Orthogonal Polygons--作业
-E. Triangulation
-E. Triangulation--作业
-F. Triangulating Monotone Polygons
--03-F-02. Monotonicity Testing
--03-F-04. Stack-Chain Consistency
-F. Triangulating Monotone Polygons--作业
-G. Monotone Decomposition
-G. Monotone Decomposition--作业
-I. Tetrahedralization
--03-I-01. Polyhedron Decomposition
--03-I-02. Schonhardt's Polyhedron
-I. Tetrahedralization--作业
-A. Introduction
--04-A-02. Dining Halls on Campus
--04-A-03. More Analogies & Applications
-A. Introduction--作业
-B. Terminologies
--04-B-02. Intersecting Halfspaces
--04-B-04. Planar Voronoi Diagram
-B. Terminologies--作业
-C. Properties
--04-C-03. Nearest = Concyclic
--04-C-04. Number of Nearest Sites = Degree
-C. Properties--作业
-D. Complexity
-D. Complexity--作业
-E. Representation
-E. Representation--作业
-F. DCEL
-F. DCEL--作业
-G. Hardness
--04-G-03. Voronoi Diagram In General Position
-G. Hardness--作业
-H. Sorted Sets
--04-H-01. Convex Hull Made Easier
--04-H-02. Convex Hull As A Combinatorial Structure
--04-H-03. Voronoi Diagram As A Geometric Structure
-H. Sorted Sets--作业
-I. VD_sorted
--04-I-06. Sorting Not Made Easier
-I. VD_sorted--作业
-J. Naive Construction
-J. Naive Construction--作业
-K. Incremental Construction
-K. Incremental Construction--作业
-L. Divide-And-Conquer
--04-L-09. Intersecting with Cells
-L. Divide-And-Conquer--作业
-M. Plane-Sweep
--04-M-09. Circle Event: What, When & Where
-M. Plane-Sweep--作业
-A. Point Set Triangulation
-A. Point Set Triangulation--作业
-B. Delaunay Triangulation
-B. Delaunay Triangulation--作业
-C. Properties
-C. Properties--作业
-D. Proximity Graph
--05-D-02. Relative Neighborhood Graph
-D. Proximity Graph--作业
-E. Euclidean Minimum Spanning Tree
-E. Euclidean Minimum Spanning Tree--作业
-F. Euclidean Traveling Salesman Problem
-G. Minimum Weighted Triangulation
-G. Minimum Weighted Triangulation--作业
-H. Construction
--05-H-03. Maximizing The Minimum Angle
--05-H-04. Evolution By Edge Flipping
-H. Construction--作业
-I. RIC With Example
-I. RIC With Example--作业
-J. Randomized Incremental Construction
--05-J-01. Recursive Implementation
--05-J-02. Iterative Implementation
-J. Randomized Incremental Construction--作业
-K. RIC Analysis
--05-K-04. Types Of Edge Change
--05-K-05. Number Of Edge Changes
--05-K-07. Number Of Rebucketings
--05-K-08. Probability For Rebucketing
--05-K-10. Further Consideration
-0. Online/Offline Algorithms
--06-0. Online/Offline Algorithms
-0. Online/Offline Algorithms--作业
-A. Introduction
--06-A-03. Assumptions For Clarity
--06-A-05. Performance Measurements
-A. Introduction--作业
-B. Slab Method
--06-B-02. Ordering Trapezoids
-B. Slab Method--作业
-C. Persistence
--06-C-01. Ephemeral Structure
--06-C-02. Persistent Structure
-C. Persistence--作业
-D. Path Copying
--06-D-03. Storage Optimization
-D. Path Copying--作业
-E. Node Copying
-E. Node Copying--作业
-F. Limited Node Copying
-G. Kirkpatrick Structure
--06-G-01. Optimal And Simpler
--06-G-06. The More The Better
--06-G-07. The Fewer The Better
--06-G-09. Existence Of Independent Subset
--06-G-10. Construction Of Independent Subset
-G. Kirkpatrick Structure--作业
-H. Trapezoidal Map
--06-H-03. Properties & Complexity
--06-H-04. Search Structure: Example
--06-H-05. Search Structure: Nodes
--06-H-06. Search Structure: Performance
-H. Trapezoidal Map--作业
-I. Constructing Trapezoidal Map
--06-I-04. Case 1: Two Endpoints
--06-I-05. Case 2: One Endpoint
--06-I-06. Case 3: No Endpoints
-J. Performance Of Trapezoidal Map
--06-J-03. Number Of Ray Trimmed
--06-J-04. Number Of Trapezoidals Created (1)
--06-J-05. Number Of Trapezoidals Created (2)
--06-J-06. Time For Point Location
--06-J-07. Size Of Search Structure
--06-J-08. Fixed Query Point + Randomly Created Maps
--06-J-10. Probability Of Enclosing Trapezoid Changed
-A. Range Query
--07-A-01. 1-Dimensional Range Query
-A. Range Query--作业
-B. BBST
--07-B-02. Lowest Common Ancestor
-B. BBST--作业
-C. kd-Tree: Structure
-C. kd-Tree: Structure--作业
-D. kd-Tree: Algorithm
-D. kd-Tree: Algorithm--作业
-E. kd-Tree: Performance
--07-E-01. Preprocessing Time + Storage
-E. kd-Tree: Performance--作业
-F. Range Tree: Structure
--07-F-03. x-Query * y-Queries
-F. Range Tree: Structure--作业
-G. Range Tree: Query
-G. Range Tree: Query--作业
-H. Range Tree: Performance
-H. Range Tree: Performance--作业
-I. Range Tree: Optimization
--07-I-04. Fractional Cascading
-A. Orthogonal Windowing Query
-A. Orthogonal Windowing Query--作业
-B. Stabbing Query
-C. Interval Tree: Construction
-C. Interval Tree: Construction--作业
-D. Interval Tree: Query
-D. Interval Tree: Query--作业
-E. Stabbing With A Segment
--08-E-03. Query Algorithm (1)
--08-E-04. Query Algorithm (2)
-F. Grounded Range Query
--08-F-03. 1D-GRQ Using Range Tree
--08-F-04. 1D-GRQ By Linear Scan
-G. 1D-GRQ Using Heap
-G. 1D-GRQ Using Heap--作业
-H. Priority Search Tree
--08-H-03. Sibling Partitioning
-H. Priority Search Tree--作业
-I. 2D-GRQ Using PST
-I. 2D-GRQ Using PST--作业
-J. Segment Tree
--08-J-01. General Windowing Query
--08-J-02. Elementary Interval
--08-J-06. Solving Stabbing Query
--08-J-11. Constructing A Segment Tree
--08-J-12. Inserting A Segment (1)
--08-J-13. Inserting A Segment (2)
--08-J-14. Inserting A Segment (3)
-K. Vertical Segment Stabbing Query