Book Image

Hyperparameter Tuning with Python

By : Louis Owen
Book Image

Hyperparameter Tuning with Python

By: Louis Owen

Overview of this book

Hyperparameters are an important element in building useful machine learning models. This book curates numerous hyperparameter tuning methods for Python, one of the most popular coding languages for machine learning. Alongside in-depth explanations of how each method works, you will use a decision map that can help you identify the best tuning method for your requirements. You’ll start with an introduction to hyperparameter tuning and understand why it's important. Next, you'll learn the best methods for hyperparameter tuning for a variety of use cases and specific algorithm types. This book will not only cover the usual grid or random search but also other powerful underdog methods. Individual chapters are also dedicated to the three main groups of hyperparameter tuning methods: exhaustive search, heuristic search, Bayesian optimization, and multi-fidelity optimization. Later, you will learn about top frameworks like Scikit, Hyperopt, Optuna, NNI, and DEAP to implement hyperparameter tuning. Finally, you will cover hyperparameters of popular algorithms and best practices that will help you efficiently tune your hyperparameter. By the end of this book, you will have the skills you need to take full control over your machine learning models and get the best models for the best results.
Table of Contents (19 chapters)
1
Section 1:The Methods
8
Section 2:The Implementation
13
Section 3:Putting Things into Practice

Understanding BOHB

Bayesian Optimization and Hyper Band (BOHB) is an extension of HB that is superior to CFS, SH, and HB, in terms of understanding the relationship between the hyperparameter candidates and the objective function. If CFS, SH, and HB are all part of the informed search group based on random search, BOHB is an informed search group that is based on the BO method. This means BOHB is able to decide which subspace needs to be searched based on previous experiences rather than luck.

As its name implies, BOHB is the combination of the BO and HB methods. While SH and HB can also be utilized with other black-box methods (see the Understanding SH and Understanding HB sections), BOHB is specifically designed to utilize a BO method in a way that can support HB. Furthermore, the BO method in BOHB also tracks all the previous evaluations on all budgets, so that it can serve as the base for future evaluations. Note that the BO method used in BOHB is the multivariate TPE, which...