Book Image

Hands-On Unsupervised Learning with Python

By : Giuseppe Bonaccorso
Book Image

Hands-On Unsupervised Learning with Python

By: Giuseppe Bonaccorso

Overview of this book

Unsupervised learning is about making use of raw, untagged data and applying learning algorithms to it to help a machine predict its outcome. With this book, you will explore the concept of unsupervised learning to cluster large sets of data and analyze them repeatedly until the desired outcome is found using Python. This book starts with the key differences between supervised, unsupervised, and semi-supervised learning. You will be introduced to the best-used libraries and frameworks from the Python ecosystem and address unsupervised learning in both the machine learning and deep learning domains. You will explore various algorithms, techniques that are used to implement unsupervised learning in real-world use cases. You will learn a variety of unsupervised learning approaches, including randomized optimization, clustering, feature selection and transformation, and information theory. You will get hands-on experience with how neural networks can be employed in unsupervised scenarios. You will also explore the steps involved in building and training a GAN in order to process images. By the end of this book, you will have learned the art of unsupervised learning for different real-world challenges.
Table of Contents (12 chapters)

Soft clustering

All of the algorithms that were analyzed in Chapter 4, Hierarchical Clustering in Action, belong to the family of hard clustering methods. This means that a given sample is always assigned to a single cluster. On the other hand, soft clustering is aimed at associating each sample, xi with a vector, generally representing the probability that xi belongs to every cluster:

Alternatively, the output can be interpreted as a membership vector:

Formally, there are no differences between the two versions, but normally, the latter is employed when the algorithm is not explicitly based on a probability distribution. However, for our purposes, we always associate c(xi) with a probability. In this way, the reader is incentivized to think about the data-generating process that has been used to obtain the dataset. A clear example is the interpretation of such vectors as the...