Book Image

Mastering Machine Learning Algorithms

Book Image

Mastering Machine Learning Algorithms

Overview of this book

Machine learning is a subset of AI that aims to make modern-day computer systems smarter and more intelligent. The real power of machine learning resides in its algorithms, which make even the most difficult things capable of being handled by machines. However, with the advancement in the technology and requirements of data, machines will have to be smarter than they are today to meet the overwhelming data needs; mastering these algorithms and using them optimally is the need of the hour. Mastering Machine Learning Algorithms is your complete guide to quickly getting to grips with popular machine learning algorithms. You will be introduced to the most widely used algorithms in supervised, unsupervised, and semi-supervised machine learning, and will learn how to use them in the best possible manner. Ranging from Bayesian models to the MCMC algorithm to Hidden Markov models, this book will teach you how to extract features from your dataset and perform dimensionality reduction by making use of Python-based libraries such as scikit-learn v0.19.1. You will also learn how to use Keras and TensorFlow 1.x to train effective neural networks. If you are looking for a single resource to study, implement, and solve end-to-end machine learning problems and use-cases, this is the book you need.
Table of Contents (22 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
13
Deep Belief Networks
Index

Factor analysis


Let's suppose we have a Gaussian data generating process, pdata N(0Σ), and M n-dimensional zero-centered samples drawn from it:

If pdata has a mean μ ≠ 0, it's also possible to use this model, but it's necessary to account for this non-null value with slight changes in some formulas. As the zero-centering normally has no drawbacks, it's easier to remove the mean to simplify the model.

One of the most common problems in unsupervised learning is finding a lower dimensional distribution plower such that the Kullback-Leibler divergence with pdata is minimized. When performing a factor analysis (FA), following the original proposal published in EM algorithms for ML factor analysis, Rubin D., Thayer D., Psychometrika, 47/1982, Issue 1, and The EM algorithm for Mixtures of Factor Analyzers, Ghahramani Z., Hinton G. E., CRC-TG-96-1, 05/1996, we start from the assumption to model the generic sample x as a linear combination of Gaussian latent variables, z, (whose dimension p is...