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

Chapter 3. Fast SVM Implementations

Having experimented with online-style learning in the previous chapter, you may have been surprised by its simplicity yet effectiveness and scalability in comparison to batch learning. In spite of learning just one example at a time, SGD can approximate the results well as if all the data resides in the core memory and you were using a batch algorithm. All you need is that your stream be indeed stochastic (there are no trends in data) and that the learner is tuned well to the problem (the learning rate is often the key parameter to be fixed).

Anyway, examining such achievements closely, the results are still just comparable to batch linear models but not to learners that are more sophisticated and characterized by higher variance than bias, such as SVMs, neural networks, or bagging and boosting ensembles of decision trees.

For certain problems, such as tall and wide but sparse data, just linear combinations may be enough according to the observation that...