Module 1: Probabilistic Graphical Models: Representation, Inference, and Learning
Probabilistic graphical models play a central role in modern statistics, machine learning, and artificial intelligence. Within these contexts, researchers and practitioners alike are often interested in modeling the conditional independencies among variables within some complex system. Graphical models address this problem via a union of probability and combinatorics: Namely, a probabilistic graphical model associates jointly distributed random variables in the system with the nodes of a graph and then encodes conditional independence relations entailed by the joint distribution in the edge structure of the graph. Consequently, the combinatorial properties of the graph come to play a critical role in our understanding of the model.
By way of the combinatorial properties of the graph in our graphical model, we gain three main advantages: (1) transparent and tractable representations of our model, (2) effective approaches to exact inference, and (3) data-driven model learning techniques. In this module, we will discuss each of these three advantages as they exist for probabilistic graphical models associated to undirected and directed acyclic graphs. For each topic we will take a close look at the role played by the combinatorial properties of the graph in helping us address these fundamental problems.
Teachers
Svante Linusson (linusson@kth.se)
Liam Solus (solus@kth.se)
Course Literature
The following set of introductory notes and recommended textbooks can be used in conjunction with this course. In the schedule below, suggested reading associated to each lecture can be found. The main books for the course will be resources (2) and (4).
1. Introductory Notes, WASP Graphical Models Course, Module 1. Download Introductory Notes, WASP Graphical Models Course, Module 1.
2. Lauritzen, Steffen. Graphical models. Vol. 17. Clarendon Press, 1996.
3. Koller, Daphne, and Nir Friedman. Probabilistic graphical models: principles and techniques. MIT press, 2009.
4. Chickering, David Maxwell. "Optimal structure identification with greedy search." Journal of machine learning research 3.Nov (2002): 507-554.
Examination
Performance in the course will be assessed based on two things: (1) participants will need to earn at least 70% of the points possible over two homework assignments. The first homework assignment is due September 20 and the second homework assignment is due October 13. (2) Participation in the two day meeting on September 27-28 at KTH (or online depending on the pandemic), during which students must attend the lectures and participate in the problem sessions. Information on the two day meeting can be found in the schedule below.
Those participants that specialize in module 1 will also be required to earn at least 70% of the points possible on a third homework assignment that will be distributed to those participants toward the end of the course (date to be announced).
Homework Assignments
The following links will become active when the homework assignments are available:
Homework Assignment 1 Download Homework Assignment 1 (Due: 20 September 2021 at 23.59)
Homework Assignment 2 Download Homework Assignment 2 (Due: 24 October 2021 at 23.59)
Homework Assignment 3 Download Homework Assignment 3 (Due: 28 February 2022 at 23.59)
Your solutions set to homework 1 should be uploaded here.
Your solutions set to homework 2 should be uploaded here.
Your solutions set to homework 3 should be uploaded here.
Socializing Opportunity on 27 September at 20.00
In the schedule below, on the evening of 27 September is an event named "Socializing." Despite the pandemic and having to hold the course virtually, we know that it is important to have some time to socialize with other WASP students. So Danai Deligeorgaki and Albin Toft have created a wonder.me space where anyone who would like to catch up with friends are welcome. The link for the activity is in the schedule below. Either Danai or Albin will also be in the main zoom room for the course in case anyone is having trouble connecting to the wonder.me page. This event is just for the students, so no professors will be present.
Schedule
The following schedule specifies the dates and times of each activity associated with the course, their content, and the associated recommended reading for the lectures. The schedule also specifies important deadlines (e.g. due dates for assignments). The online lectures for the course will take place at the zoom link here:
ZOOM LINK: https://kth-se.zoom.us/j/67240814358 Links to an external site.
For the activities such as "lunch," "dinner," and "socializing," it is of course not required that participants attend. However, we will have zoom breakout rooms open at these times so that you can eat together and socialize with friends that you cannot meet with in person due to the pandemic.
In the Suggested Reading column, KF and L refer to references 3 and 2 above, respectively.
Date | Time | Teacher | Suggested Reading | Content | Notes | Deadlines |
Aug 30 |
13.00-15.00 | Svante | KF 2.2, Introductory notes |
Graph theory basics | Slides GraphTheory
Download Slides GraphTheory zoom chat Download zoom chat |
Homework Set 1 Download Homework Set 1 handed out |
Sept 6 | 15.00-17.00 | Liam | KF 1.1, 1.2, 2.1 | What are graphical models? Probability basics and first examples | notes and zoom chat Download notes and zoom chat | |
Sept 20 | Homework Set 1 due | |||||
Sept 27 | 13.00-14.00 | Liam | L 3.1, 3.2.1 | Representation: Undirected Graphical Models and the Hammersley-Clifford Theorem | notes Download notes | |
Sept 27 | 14.00-15.00 | Practice Session | ||||
Sept 27 | 15.00-16.00 | Svante | L 3.2.2 | Representation: DAG models, and the Directed Factorization Theorem | notes2 Download notes2 | |
Sept 27 | 16.00-17.00 | Practice Session | practice-2
Download practice-2 Solutions-2 Download Solutions-2 |
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Sept 27 | 17.00-18.00 | Svante | KF 3.3.4 | Learning: Markov equivalence | notes3 Download notes3 | |
Sept 27 | 18.00-19.00 | Practice Session | practice-3
Download practice-3 Solutions-3 Download Solutions-3 |
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Sept 27 | 19.00-20.00 | Dinner | ||||
Sept 27 | 20.00-23.59 | Socializing | wonder.me link Links to an external site. | |||
Sept 28 | 9.00-10.00 | Liam | KF 18.1, 18.2, 18.3, Chickering paper | Learning: Constraint-based and greedy approaches to learning DAG representations from data | notes Download notes | |
Sept 28 | 10.00-11.00 | Practice Session | ||||
Sept 28 | 11.00-12.00 | Liam | KF 9 | Exact Inference: Variable Elimination, Complexity and Tree-width | notes Download notes | |
Sept 28 | 12.00-13.00 | Lunch | ||||
Sept 28 | 13.00-14.00 | Practice Session | ||||
Sept 28 | 14.00-15.00 | Svante | KF 10 | Exact Inference: The Clique-tree Algorithm | notes Download notes | |
Sept 28 | 15.00-16.00 | Practice Session | ||||
Sept 28 | 16.00 | Farewell! | ||||
Sept 29 | Homework set 2 handed out | |||||
Oct 13 | Homework Set 2 due | |||||
Homework Set 3 handed out | ||||||
Homework Set 3 due |