Computational Geometry 202-2-5121
Fall 2018

Prerequisite: Algorithms


Announcements:


Instructor:

Matya Katz  ( matya@cs.bgu.ac.il ) 

Office hours: Sunday 12:00-14:00, Alon building (37), room 212, Tel: (08) 6461628

 

Teaching Assistant:

          Omrit Filtser

 

Class Time:

Wednesday 12-14 (building 90, room 139)

Thursday 10-12 (building 90, room 123)


Course Description:

This is an introductory course to computational geometry and its applications. We will present data structures, algorithms and general techniques for solving fundamental geometric problems, such as convex hull computation, line segment intersection, orthogonal range searching, construction of Voronoi diagram and Delaunay triangulation, polygon triangulation, and linear programming. We will also present several geometric (optimization) algorithms (both exact and approximate) for problems in robotics, computer graphics, GIS (geographic information systems), communication networks, facility location, and VLSI systems design.
 


Bibliography:

The main textbook of the course is

[dBCvKO] Computational Geometry: Algorithms and Applications (3rd edition),
M. de Berg, O. Cheong, M. van Kreveld and M. Overmars, Springer-Verlag, 2008.
 

Additional textbooks

[BY] Algorithmic Geometry, J-D Boissonnat and M. Yvinec, Cambridge University Press, 1998.

 

[DO] Discrete and Computational Geometry, S. Devadoss and J. O’Rourke, Princeton University Press, 2011.

[E] Algorithms in Combinatorial Geometry, H. Edelsbrunner, Springer-Verlag, 1987.

[M] Computational Geometry: An Introduction Through Randomized Algorithms, K. Mulmuley, Prentice Hall, 1994.

[O] Computational Geometry in C (2nd edition), J. O'Rourke, Cambridge University Press, 1998.

[PS] Computational Geometry: An Introduction (2nd edition), F. Preparata and M. Shamos, Springer-Verlag, 1988.


Assignments, Exam and Grades:

The final grade will be determined by 3-5 homework assignments (4% each) and a final exam.

 

Some of the exercises in the HW assignments are taken from [dBCvKO].

 

Assignment 1 (due Nov. 14, 2018)

Assignment 2 (due Dec. 6  9, 2018)

Assignment 3 (due Jan.  3  6, 2019)

Assignment 4 (due Jan. 10, 13, 2019)

 

 

Some old exams: exam 2005 A; exam 2005 B; exam 2007 A; exam 2007 B; exam 2009 A; exam 2009 B; exam 2016 A


Topics:

The following list of topics is tentative.

The convex hull of a set of points in the plane (applications: computing the diameter and width of a point set).

An output sensitive algorithm for computing the intersection points of a set of line segments; the plane sweep technique.

A representation for planar maps (based on doubly-connected edge lists).

Computing the overlay of two planar maps; Boolean operations on two polygons (union, intersection, and difference).

The art gallery theorem; introduction to polygon triangulation.

An O(n log n) polygon triangulation algorithm (partitioning a polygon into y-monotone pieces; triangulating a y-monotone polygon).

Orthogonal range searching.  

Computing the intersection of n half planes in O(n log n) time.

Linear programming - introduction; A randomized incremental algorithm for linear programming in the plane.

Planar point location, vertical decomposition / trapezoidal map, a randomized incremental algorithm.

Nearest site queries, nearest site Voronoi diagram.

Triangulation of a set of points in the plane; the Delaunay triangulation.

Arrangement of lines; duality; computing the discrepancy of a set of points in the unit square.

Segment trees; computing the area of a set of n axis-parallel rectangles in O(n log n) time.

Simplex range searching.

Hidden surface removal: problem definition, image space / object space, the z-buffer algorithm, depth order, the painter's algorithm. Output sensitive hidden surface removal algorithm for horizontal fat triangles.  

Introduction to geometric optimization through facility location optimization and wireless networks.

Measures of similarity between curves.

 


Course summary:

Below you will find, after each class, a brief summary of the topics covered in class.
This should not be taken as a complete description of the course's content.


17.10.18
Introduction

 

18.10.18

The convex hull of a set of points in the plane (gift wrapping, quickhullan O(n log n)-time incremental algorithm)

 

24.10.18

A divide and conquer algorithm for computing the CH in the plane. Remarks concerning the CH in higher dimensions. The diameter and width of a set of points in the plane; rotating calipers.

 

25.10.18

Sweeping; an output-sensitive algorithm for line segment intersection.

 

31.10.18

Sweeping with a ray; Implementing the decision problem “do two line segments intersect?” and a more general discussion on implementation issues and general position

 

1.11.18

The doubly-connected edge list representation (DCEL) for planar maps; Map overlay (problem definition and statement of result only); Boolean operations on polygons

 

7.11.18

The art gallery theorem, introduction to guarding

 

8.11.18

Partitioning a polygon into y-monotone pieces

 

14.11.18

Triangulating a y-monotone polygon

 

15.11.18

Orthogonal range searching – Inro, Kd-trees

 

21.11.18

Kd-tree continued, Orthogonal Range Trees

 

22.11.18

Segment trees

 

28.11.18

Computing the area of a set of n axis-parallel rectangles in O(n log n) time

 

29.11.18

Computing the intersection of n half planes in O(n log n) time. Inro to linear programming

 

5.12.18

Linear programming - A randomized incremental algorithm for linear programming in the plane

 

6.12.18

Planar point location, vertical decomposition / trapezoidal map, a randomized incremental algorithm

 

12.12.18

Point location - continued. Intro to Voronoi diagrams

 

13.12.18

Voronoi diagrams – definitions, properties, and extensions

 

19.12.18

Measures of similarity between curves, the Fréchet distance, etc. (Omrit Filtser)

 

20.12.18

Triangulation of a set of points in the plane; the Delaunay triangulation.

 

26.12.18

Arrangement of lines; duality; k-set/k-level.

 

27.12.18

Optimization: A 3/2-approximation algorithm for TSP in the plane.

 

2.1.19

Optimization: Intro to piercing and covering.

 

3.1.19

Optimization: Covering continued; radio networks and the power assignment problem.

 

9.1.19

Optimization: radio networks continued.

 

10.1.19

Summary

 

 

Last update: January 9, 2019