Spark 2.0 has been released since last July but, despite the numerous improvements and new features, several annoyances still remain and can cause headaches, especially in the Spark machine learning APIs. Today we’ll have a look at some of them, inspired by a recent answer of mine in a Stack Overflow question (the question was about Spark 1.6 but, as …
Limitations of Spark MLlib linear algebra module
A couple of days ago I stumbled upon some unexpected behavior of Spark MLlib (v. 1.5.2), while trying some ultra-simple operations on vectors. Consider the following Pyspark snippet: Clearly, what happens is that the unary operator – (minus) for vectors fails, giving errors for expressions like -x and -y+x, although x-y behaves as expected. The result of the last operation, …
Development and deployment of Spark applications with Scala, Eclipse, and sbt – Part 2: A Recommender System
In our previous post, we demonstrated how to setup the necessary software components, so that we can develop and deploy Spark applications with Scala, Eclipse, and sbt. We also included the example of a simple application. In this post, we are taking this demonstration one step further. We discuss a more serious application of a recommender system and present the …