Past Meetup

Unsupervised Learning and Multinomial Logistic Regression with Apache Spark

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This is the second event in this series talking about Machine Learning with Spark!

It's our pleasure to have two speakers in this event. Sandy Ryza from Cloudera will give a talk about unsupervised learning with Spark. DB Tsai from Alpine Data Labs will talk about multinomial logistic regression with L-BFGS optimizer with Spark.

Part1 - Sandy Ryza:

Unsupervised learning refers to a branch of algorithms that try to find structure in unlabeled data. Clustering algorithms, for example, try to partition elements of a dataset into related groups. Dimensionality reduction algorithms search for a simpler representation of a dataset. Spark's MLLib module contains implementations of several unsupervised learning algorithms that scale to huge datasets. In this talk, we'll dive into uses and implementations of Spark's K-means clustering and Singular Value Decomposition (SVD).

Part2 - DB Tsai:

Logistic Regression can not only be used for modeling binary outcomes but also multinomial outcome with some extension. In this talk, DB will talk about basic idea of binary logistic regression step by step, and then extend to multinomial one. He will show how easy it's with Spark to parallelize this iterative algorithm by utilizing the in-memory RDD cache to scale horizontally (the numbers of training data.) However, there is mathematical limitation on scaling vertically (the numbers of training features) while many recent applications from document classification and computational linguistics are of this type. He will talk about how to address this problem by L-BFGS optimizer instead of Newton optimizer.


Sandy Ryza is an engineer on the data science team at Cloudera. He is a committer on Apache Hadoop and recently led Cloudera's Apache Spark development.

DB Tsai is a machine learning engineer working at Alpine Data Labs. He is recently working with Spark MLlib team to add support of L-BFGS optimizer and multinomial logistic regression in the upstream. He also led the Apache Spark development at Alpine Data Labs. Before joining Alpine Data labs, he was working on large-scale optimization of optical quantum circuits at Stanford as a PhD student.