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

Implementing Successive Halving

Successive Halving (SH) is implemented as a pruner in Optuna, meaning that it is responsible for stopping hyperparameter tuning iterations whenever it seems that there’s no additional benefit to continuing the process. Since it is implemented as a pruner, the resource definition of SH (see Chapter 6) in Optuna refers to the number of training steps or epochs of the model, instead of the number of samples, as it does in scikit-learn’s implementation.

We can utilize SH as a pruner along with any sampler that we use. This example shows you how to perform hyperparameter tuning with the Random Search algorithm as the sampler and SH as the pruner. The overall procedure is similar to the procedure stated in the Implementing TPE section. Since we are utilizing SH as a pruner, we have to edit our objective function so that it will utilize the pruner during the optimization process. In this example, we can use the callback integration with TFKeras...