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)

Hierarchical Clustering in Action

In this chapter, we are going to discuss the concept of hierarchical clustering, which is a powerful and widespread technique for generating a complete hierarchy of clustering configurations, starting with either a single cluster equivalent to the dataset (the divisive approach) or a number of clusters equal to the number of samples (the agglomerative approach). This method is particularly helpful when it's necessary to analyze the whole grouping process at once in order to understand, for example, how smaller clusters are merged into larger ones.

In particular, we will discuss the following topics:

  • Hierarchical clustering strategies (divisive and agglomerative)
  • Distance metrics and linkage methods
  • Dendrograms and their interpretation
  • Agglomerative clustering
  • Cophenetic correlation as a performance measure
  • Connectivity constraints

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