Class meeting for 10-405 LDA

This is one of the class meetings on the schedule for the course Machine Learning with Large Datasets 10-405 in Spring 2018.

Slides

• Lecture 1: Powerpoint, PDF.
• Lecture 2: Powerpoint, PDF.

Quiz

• No quiz for lecture 1
• Quiz for lecture 2

Readings

Basic LDA:

• Blei, David M., Andrew Y. Ng, and Michael I. Jordan. "Latent Dirichlet allocation." Journal of machine Learning research 3.Jan (2003): 993-1022.

Speedups for LDA:

• Distributed Algorithms for Topic Models, Newman et al, JMLR 2009.
• Efficient Methods for Topic Model Inference on Streaming Document Collections, Yao, Mimno, McCallum KDD 2009.
• Reducing the sampling complexity of topic models, Li, Ahmed, Ravi, & Smola, KDD 2014
• A Scalable Asynchronous Distributed Algorithm for Topic Modeling, Yu, Hsieh, Yun, Vishwanathan, Dillon, WWW 2015

Things to remember

• How Gibbs sampling is used to sample from a model.
• The "generative story" associated with key models like LDA, naive Bayes, and stochastic block models.
• What a "mixed membership" generative model is.
• The time complexity and storage requirements of Gibbs sampling for LDAs.
• How LDA learning can be sped up using IPM approaches.

• Why efficient sampling is important for LDAs
• How sampling can be sped up for many topics by preprocessing the parameters of the distribution
• How the storage used for LDA can be reduced by exploiting the fact that many words are rare.