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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Index

Multilayer Perceptrons (MLPs)

The main limitation of a perceptron is its linearity. How is it possible to exploit this kind of architecture by removing such a constraint? The solution is easier than you might speculate. Adding at least one non-linear layer between the input and output leads to a highly non-linear combination, parametrized with a larger number of variables. The resulting architecture, called a Multilayer Perceptron (MLP) and containing a single (just for simplicity) hidden layer, is shown in the following diagram:

Structure of a generic Multilayer Perceptron with a single hidden layer

This is a so-called feed-forward network, meaning that the flow of information begins in the first layer, always proceeds in the same direction, and ends at the output layer. Architectures that allow partial feedback (for example, in order to implement local memory) are called recurrent networks and will be analyzed in the next chapter.

In this case, there...