Book Image

Mastering Machine Learning Algorithms. - Second Edition

By : Giuseppe Bonaccorso
Book Image

Mastering Machine Learning Algorithms. - Second Edition

By: Giuseppe Bonaccorso

Overview of this book

Mastering Machine Learning Algorithms, Second Edition helps you harness the real power of machine learning algorithms in order to implement smarter ways of meeting today's overwhelming data needs. This newly updated and revised guide will help you master algorithms used widely in semi-supervised learning, reinforcement learning, supervised learning, and unsupervised learning domains. You will use all the modern libraries from the Python ecosystem – including NumPy and Keras – to extract features from varied complexities of data. Ranging from Bayesian models to the Markov chain Monte Carlo algorithm to Hidden Markov models, this machine learning book teaches you how to extract features from your dataset, perform complex dimensionality reduction, and train supervised and semi-supervised models by making use of Python-based libraries such as scikit-learn. You will also discover practical applications for complex techniques such as maximum likelihood estimation, Hebbian learning, and ensemble learning, and how to use TensorFlow 2.x to train effective deep neural networks. By the end of this book, you will be ready to implement and solve end-to-end machine learning problems and use case scenarios.
Table of Contents (28 chapters)
26
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27
Index

Summary

In this chapter, we introduced Bayesian networks, describing their structure and relations. We have seen how it's possible to build a network to model a probabilistic scenario where some elements can influence the probability of others. We have also described how to obtain the full joint probability using the most common sampling methods, which allow reducing the computational complexity through an approximation.

The most common sampling methods belong to the family of MCMC algorithms, which model the transition probability from a sample to another one as a first-order Markov chain. In particular, the Gibbs sampler is based on the assumption that it's easier to sample from a conditional distribution than work directly with the full joint probability. The method is very easy to implement, but it has some performance drawbacks that can be avoided by adopting more complex strategies.

The Metropolis-Hastings sampler, instead, works with a candidate-generating...