Video Lectures

Lecture 35: Finding Clusters in Graphs

Description

The topic of this lecture is clustering for graphs, meaning finding sets of “related” vertices in graphs. The challenge is finding good algorithms to optimize cluster quality. Professor Strang reviews some possibilities.

Summary

Two ways to separate graph nodes into clusters

  • k-means: Choose clusters, choose centroids, choose clusters, …
  • Fiedler vector: Eigenvector of graph Laplacian: \(+-\) signs give 2 clusters

Related sections in textbook: IV.6–IV.7

Instructor: Prof. Gilbert Strang

Problem for Lecture 35
From textbook Sections IV.6-IV.7

1. What are the Laplacian matrices for a triangle graph and a square graph?

Course Info

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As Taught In
Spring 2018
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