Spring 2018 - COMPSCI 630 - Randomized Algorithms

Randomization is a key technique in many settings, and is becoming more important in both theory and practice. It does not only lead to algorithms with better performance/fast running time, in some settings it also makes impossible things feasible. In this course we will see examples of the power of randomness. This will include basic techniques like linearity of expectation, union bounds and concentration of measure. We will also focus on the applications related to dimension reduction (in different settings) and Markov Chains.

Announcements

Homework 1 posted, due 2/28/2018.
Homework 2 posted, due 3/30/2018.
Homework 3 posted, due 4/18/2018.

Make up class for the snow day (1/17) is scheduled on Saturday April 14th (1:25 - 2:40 pm, D106). We will talk about stochastic optimization in that lecture.
Wednesday 1/17/2018: Classes are cancelled due to snow!

Course Information

Instructor
Rong Ge
D226 LSRC
Email: rongge@cs.duke.edu

Lectures: Monday Wednesday 1:25 - 2:40 pm in LSRC D106

Office Hour: Wednesdays 3:00 - 5:00 pm in LSRC D226. Use Piazza for discussions/clarifications.

References:
Most materials in the course can be found in one of the following books.
Randomized Algorithms, Rajeev Motwani and Prabhakar Raghavan.
Concentration of measure for the analysis of randomized algorithms by D. Dubhashi and A. Panconesi.
Probability and Computing by Michael Mitzenmacher and Eli Upfal.

Topics on matrix algorithms can be found in
Foundations of Data Science
by
Avrim Blum, John Hopcroft and Ravi Kannan.

Prerequisites: Familiarity with algorithms, probability and linear algebra.

Homework: 

Homework 0, due Friday 1/17 at 11:59 pm.

Evaluation:
The course grades will be determined based on:

Tentative Schedule
(Chapter numbers refer to Motwani and Raghavan book)

Classes were cancelled due to snow on 1/17/2018. All the lectures will be shifted by one. The make-up lecture will be on Saturday April 14.
Date Contents ScribeReferences Future Reading
Basic Properties of Random Variables
1/10 Karger's randomized algorithm for MIN CUT scribeChapter 1.1 Wiki for the Karger-Stein Algorithm
1/15Martin Luther King, Jr. Day. No class
1/17 Linearity of Expectation, MAX 3-SAT, simple recursions scribeChapter 1.4 Slides by K. Wayne
1/22 Balls and bins scribeChapter 3.1, 3.6
1/24 Hashing scribeChapter 3.4, 8.4 Chapter 8.5
1/29 Biased Coin, distance of distributions scribeChapter 3.2
Notes by Y. Mansour
Pollard's Book Chapter
Concentration Inequalities
1/31 Chernoff bounds, Bernstein Inequalities scribeChapter 4.1
2/5 Oblivious Routing scribeChapter 4.2 Lecture note by Sheideler
2/7 Power of two choices scribeNotes (A. Gupta)
Presentation(B. Vocking)
2/12 Martingales, Azuma's Inequality, Bounded Difference scribeChapter 4.4
Dimension Reductions
2/14 Dimension Reduction, Johnson-Lindenstrauss scribeChapter 2.7 in BHK
2/19 Applications of Dimension Reduction: Streaming and Communication models scribeChapter 6.2.4 in BHK
Chapter 6.1, 6.2 in BHK
2/21Locally sensitive hashingscribeNotes (A. Andoni and I. Razenshteyn)Notes on a later lecture (A. Andoni and I. Razenshteyn)
2/26 Graph Sparsification I: Spectrum of graph, effective resistance scribeChapter 6.4 Lectures (especially lecture 1) by  Nikhil Srivastava
2/28 Graph Sparsification II: matrix concentrations scribe
3/5 Randomized Algorithms for matrices, SVD and CUR decomposition scribeChapter 6.3 in BHK
3/7Sparse subspace embeddingsscribeChapter 2.1 of  David Woodruff's Survey
3/12,3/14Spring recess, no class
Markov Chains
3/19 Random walk on graph, stationary distributions scribeChapter 6.2 Chapter 6.1
Chapter 4.1 in BHK
3/21 Resistor network revisited.
scribeChapter 6.3 - 6.4
Chapter 4.5 in BHK
3/26 Expanders, fast mixing  scribeChapter 6.7 Luca Trevisan's note
3/28Hard side of Cheeger's inequalityscribeChapter 6.7Shayan Oveis Gharan's note
4/2 Approximate Counting I: DNF counting scribeChapter 11.1-11.2
4/4 Approximate Counting II: Matchings, MCMC scribeChapter 11.3 Chapter 11.4
Special Topics
4/9Stochastic Optimization
4/11 Near linear time Laplacian solvers Slide by Lorenzo Orecchia Paper
4/16 Randomized complexity classes, derandomization Chapter 7.2 (for PIT) Luca Trevisan's slides
4/18 Constructive Lovasz Local Lemma
scribeChapter 5.5 Lance Fortnow's Blog Post
Ronitt Rubinfeld's Lecture Note
(with longer but more general proof)
Time TBDTake Home Final