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There are 7 modules in this course
Probabilistic graphical models (PGMs) are a rich framework for encoding probability distributions over complex domains: joint (multivariate) distributions over large numbers of random variables that interact with each other. These representations sit at the intersection of statistics and computer science, relying on concepts from probability theory, graph algorithms, machine learning, and more. They are the basis for the state-of-the-art methods in a wide variety of applications, such as medical diagnosis, image understanding, speech recognition, natural language processing, and many, many more. They are also a foundational tool in formulating many machine learning problems.
This course is the second in a sequence of three. Following the first course, which focused on representation, this course addresses the question of probabilistic inference: how a PGM can be used to answer questions. Even though a PGM generally describes a very high dimensional distribution, its structure is designed so as to allow questions to be answered efficiently. The course presents both exact and approximate algorithms for different types of inference tasks, and discusses where each could best be applied. The (highly recommended) honors track contains two hands-on programming assignments, in which key routines of the most commonly used exact and approximate algorithms are implemented and applied to a real-world problem.
This module provides a high-level overview of the main types of inference tasks typically encountered in graphical models: conditional probability queries, and finding the most likely assignment (MAP inference).
What's included
2 videos
Show info about module content
2 videos•Total 25 minutes
Overview: Conditional Probability Queries•15 minutes
Overview: MAP Inference•10 minutes
Variable Elimination
Module 2•1 hour to complete
Module details
This module presents the simplest algorithm for exact inference in graphical models: variable elimination. We describe the algorithm, and analyze its complexity in terms of properties of the graph structure.
What's included
4 videos1 assignment
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4 videos•Total 56 minutes
Variable Elimination Algorithm•16 minutes
Complexity of Variable Elimination•13 minutes
Graph-Based Perspective on Variable Elimination•15 minutes
Finding Elimination Orderings•12 minutes
1 assignment•Total 30 minutes
Variable Elimination•30 minutes
Belief Propagation Algorithms
Module 3•18 hours to complete
Module details
This module describes an alternative view of exact inference in graphical models: that of message passing between clusters each of which encodes a factor over a subset of variables. This framework provides a basis for a variety of exact and approximate inference algorithms. We focus here on the basic framework and on its instantiation in the exact case of clique tree propagation. An optional lesson describes the loopy belief propagation (LBP) algorithm and its properties.
What's included
9 videos2 assignments1 programming assignment
Show info about module content
9 videos•Total 150 minutes
Belief Propagation Algorithm•21 minutes
Properties of Cluster Graphs•15 minutes
Properties of Belief Propagation•10 minutes
Clique Tree Algorithm - Correctness•18 minutes
Clique Tree Algorithm - Computation•16 minutes
Clique Trees and Independence•15 minutes
Clique Trees and VE•16 minutes
BP In Practice•16 minutes
Loopy BP and Message Decoding•22 minutes
2 assignments•Total 60 minutes
Message Passing in Cluster Graphs•30 minutes
Clique Tree Algorithm•30 minutes
1 programming assignment•Total 900 minutes
Exact Inference•900 minutes
MAP Algorithms
Module 4•2 hours to complete
Module details
This module describes algorithms for finding the most likely assignment for a distribution encoded as a PGM (a task known as MAP inference). We describe message passing algorithms, which are very similar to the algorithms for computing conditional probabilities, except that we need to also consider how to decode the results to construct a single assignment. In an optional module, we describe a few other algorithms that are able to use very different techniques by exploiting the combinatorial optimization nature of the MAP task.
What's included
5 videos1 assignment
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5 videos•Total 74 minutes
Max Sum Message Passing•20 minutes
Finding a MAP Assignment•4 minutes
Tractable MAP Problems•15 minutes
Dual Decomposition - Intuition•18 minutes
Dual Decomposition - Algorithm•16 minutes
1 assignment•Total 30 minutes
MAP Message Passing•30 minutes
Sampling Methods
Module 5•14 hours to complete
Module details
In this module, we discuss a class of algorithms that uses random sampling to provide approximate answers to conditional probability queries. Most commonly used among these is the class of Markov Chain Monte Carlo (MCMC) algorithms, which includes the simple Gibbs sampling algorithm, as well as a family of methods known as Metropolis-Hastings.
What's included
5 videos2 assignments1 programming assignment
Show info about module content
5 videos•Total 100 minutes
Simple Sampling•24 minutes
Markov Chain Monte Carlo•14 minutes
Using a Markov Chain•15 minutes
Gibbs Sampling•19 minutes
Metropolis Hastings Algorithm•27 minutes
2 assignments•Total 44 minutes
Sampling Methods•14 minutes
Sampling Methods PA Quiz•30 minutes
1 programming assignment•Total 720 minutes
Sampling Methods•720 minutes
Inference in Temporal Models
Module 6•1 hour to complete
Module details
In this brief lesson, we discuss some of the complexities of applying some of the exact or approximate inference algorithms that we learned earlier in this course to dynamic Bayesian networks.
What's included
1 video1 assignment
Show info about module content
1 video•Total 20 minutes
Inference in Temporal Models•20 minutes
1 assignment•Total 30 minutes
Inference in Temporal Models•30 minutes
Inference Summary
Module 7•1 hour to complete
Module details
This module summarizes some of the topics that we covered in this course and discusses tradeoffs between different algorithms. It also includes the course final exam.
What's included
1 video1 assignment
Show info about module content
1 video•Total 13 minutes
Inference: Summary•13 minutes
1 assignment•Total 30 minutes
Inference Final Exam•30 minutes
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The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto, California, United States.
Learning Outcomes: By the end of this course, you will be able to take a given PGM and
Execute the basic steps of a variable elimination or message passing algorithm
Understand how properties of the graph structure influence the complexity of exact inference, and thereby estimate whether exact inference is likely to be feasible
Go through the basic steps of an MCMC algorithm, both Gibbs sampling and Metropolis Hastings
Understand how properties of the PGM influence the efficacy of sampling methods, and thereby estimate whether MCMC algorithms are likely to be effective
Design Metropolis Hastings proposal distributions that are more likely to give good results
Compute a MAP assignment by exact inference
Honors track learners will be able to implement message passing algorithms and MCMC algorithms, and apply them to a real world problem
When will I have access to the lectures and assignments?
To access the course materials, assignments and to earn a Certificate, you will need to purchase the Certificate experience when you enroll in a course. You can try a Free Trial instead, or apply for Financial Aid. The course may offer 'Full Course, No Certificate' instead. This option lets you see all course materials, submit required assessments, and get a final grade. This also means that you will not be able to purchase a Certificate experience.
What will I get if I subscribe to this Specialization?
When you enroll in the course, you get access to all of the courses in the Specialization, and you earn a certificate when you complete the work. Your electronic Certificate will be added to your Accomplishments page - from there, you can print your Certificate or add it to your LinkedIn profile.
Is financial aid available?
Yes. In select learning programs, you can apply for financial aid or a scholarship if you can’t afford the enrollment fee. If fin aid or scholarship is available for your learning program selection, you’ll find a link to apply on the description page.