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Princeton University
Computer Science Department

Computer Science 521
Advanced Algorithm Design
  

Sanjeev Arora


  Fall 2013

Course Summary

(Important: In light of the new grad course requirements, this course is changing as of Fall 2013 to make it more accessible to CS grads who are not specializing in theoretical CS. )
 
Design and analysis of algorithms is an important part of computer science today. This course gives a broad yet deep exposure to algorithmic advances of the past few decades, and brings students up to a level where they can read and understand research papers in algorithms. The course is suitable for advanced undergrads and non-CS grads as well, and they will be graded on a different curve.  Grads who intend to specialize in theoretical CS are invited to attend extra discussions (at Small World coffee on Friday afternoon) that explore some topics in greater depth.

Thematically, the biggest difference from undergrad algorithms (such as COS 423) is extensive use of ideas such as randomness, approximation, high dimensional geometry,  which are increasingly important in most applications. We will encounter notions such as algorithm design in face of uncertainty, approaches to handle big data, handling intractability, heuristic approaches, etc. We will develop all necessary mathematical tools.

Prerequisites:  One undergraduate course in algorithms (eg COS 423), or equivalent mathematical maturity. Listeners and auditors are welcome with prior permission.

Coursework: Two lectures/week.  For motivated students, a 1-hour discussion of advanced ideas each week at Small World Coffee on Friday afternoon. There will be 4 homeworks over the semester, which may include some simple programming-based exploration of the lecture ideas using Matlab or other packages. (Collaboration OK on homeworks.) There will be a take-home final in January. Grads not specializing in theoretical CS will be allowed to substitute a course project (done in groups of 2) + one extra homework for the final.  There is no official text. Instead, we will use assorted online resources. Students will be expected to scribe lecture notes once or twice during the term.


Administrative Information

Lectures: Tues-Thurs 13:30-15:00   Room 402 . First meeting: Sept 12.

Instructor: Sanjeev Arora- 307 CS Building - 609-258-3869 arora AT the domain name cs.princeton.edu

Teaching assistant: Aman Dhesi adhesi  AT the domain name cs.princeton.edu      

ENROLLED STUDENTS SHOULD ADD THEMSELVES TO THE DISCUSSION LIST AT PIAZZA.COM

Office hrs: Sanjeev Monday 3:30-5pm in Room 307 and by appointment.
                   Aman Wed 12-1:30pm             



Tentative course outline



1.     Hash for breakfast, lunch and dinner.  (2 lectures)

2.     Power of randomized choices.  (2 lectures)

3.     Linear programs to find solutions to life's constraints. (1 lecture)

4.     Approximation as a workaround for intractability: Part 1. (1 lecture)

5.     Play a game, manage your riches ---no regret! (2 lectures)

6.     Looking at a problem in more than one way: duality. (2 lectures)

7.     Expand your mind: taking things to a higher dimension. (1 lecture)
  "The key to growth is introduction of higher dimensions of consciousness.." [LaoTzu]

8.     How to swim against the stream: sketches of big data. (1 lecture)

9.     The power of the spectrum: random walks, clustering, graph decomposition. (2 lectures)

10. Solving a linear program including LPs too big to write down. (sketch). (1 lecture).

11. Feasible approaches to nonlinear problems:  Semidefinite programs. (1 lecture)

12. Metric spaces and how to think about them.  (2 lectures)

13. Algorithms that don't always work: Heuristics. (2 lectures)

 MCMC. Local search/gradient descent.  SAT Solvers.

14. How to do many things at once: multiprocessing (1 lecture)

15. Algorithmic view of modeling (1 lecture)

16. Algorithms in machine learning.



Lecture notes + readings


Lecture number + Title
Required reading
Further reading + links
1) (Sept 12) How is this course different from undergrad algorithms?
   Hashing Part 1.
Lecture 1 notes.

2) Karger's min cut algorithm (and its extensions).A simple and gorgeous intro to randomized algorithms.
Lecture 2 notes
(includes extracts from lecture notes of S. Dasgupta and E. Vigoda)

3) Deviation bounds and their applications.
Bounds by Markov, Chebyshev and Chernoff on how much and how often a random variable deviates from its expectation. Applications to Load Balancing and sampling.
Lecture 3 notes.

Survey of concentration inequalities by Chung and Lu
4) Hashing to real numbers and its big-data applications. Estimating the size of a set that's too large to write down. Estimating the similarity of two documents using their hashes.
Lecture 4 notes.

5) Sept 24: Linear thinking. (Linear modeling, linear equations and inequalities, linear programming. )
Lecture 5 notes .
Also see section 7.1 of relevant chapter from Dasgupta, Papadimitriou, Vazirani (ugrad text).

Analysis of Gaussian elimination (notes by Peter Gacs)
6) Provable Approximation via Linear Programming.
(Min vertex cover, MAX-2SAT, Virtual Circuit routing)
Lecture 6 notes.




Homeworks

  1. Homework 1. Due Thurs Oct 3 in class.



Resources and Readings


Further reading (books)

This course presents "greatest hits" of algorithms research and/or "must-know foundational ideas."  Usually the topics are covered in greater detail in specific textbooks.  Here are some great resources for additional reading:
  1. Randomized Algorithms by Motwani and Raghavan.
  2. Online computation and online analysis by Borodin and El-Yaniv.
  3. Probabilistic Method by Alon and Spencer.
  4. Approximation algorithms by Vijay Vazirani.
  5. Design of approximation algorithms (legal download) by Williamson and Shmoys
  6. Spectral graph theory by Fan Chung.
  7. Mining of massive datasets by Rajaraman, Leskovec, Ullmann.
  8. Algorithmic Game Theory (nonprintable legal version) by Nisan, Roughgarden, Tardos, Vazirani.


Readings for Friday Section

(for students who come to the Friday meetings)


Date and topic
Reading
Additional reading/links
1) Random graph theory, indep. set in random graphs, random 3SAT.