Book Image

Large Scale Machine Learning with Python

By : Bastiaan Sjardin, Alberto Boschetti
Book Image

Large Scale Machine Learning with Python

By: Bastiaan Sjardin, Alberto Boschetti

Overview of this book

Large Python machine learning projects involve new problems associated with specialized machine learning architectures and designs that many data scientists have yet to tackle. But finding algorithms and designing and building platforms that deal with large sets of data is a growing need. Data scientists have to manage and maintain increasingly complex data projects, and with the rise of big data comes an increasing demand for computational and algorithmic efficiency. Large Scale Machine Learning with Python uncovers a new wave of machine learning algorithms that meet scalability demands together with a high predictive accuracy. Dive into scalable machine learning and the three forms of scalability. Speed up algorithms that can be used on a desktop computer with tips on parallelization and memory allocation. Get to grips with new algorithms that are specifically designed for large projects and can handle bigger files, and learn about machine learning in big data environments. We will also cover the most effective machine learning techniques on a map reduce framework in Hadoop and Spark in Python.
Table of Contents (17 chapters)
Large Scale Machine Learning with Python
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Feature selection by regularization


In a batch context, it is common to operate feature selection by the following:

  • A preliminary filtering based on completeness (incidence of missing values), variance, and high multicollinearity between variables in order to have a cleaner dataset of relevant and operable features.

  • Another initial filtering based on the univariate association (chi-squared test, F-value, and simple linear regression) between the features and response variable in order to immediately remove the features that are of no use for the predictive task because they are little or not related to the response.

  • During modeling, a recursive approach inserting and/or excluding features on the basis of their capability to improve the predictive power of the algorithm, as tested on a holdout sample. Using a smaller subset of just relevant features allows the machine learning algorithm to be less affected by overfitting because of noisy variables and the parameters in excess due to the high...