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 Random Search

Implementing Random Search in Optuna is very similar to implementing TPE in Optuna. We can just follow a similar procedure to the preceding section and change the sampler parameter in the optimize() method in step 2. The following code shows you how to do that:

study = optuna.create_study(direction='maximize', 
sampler=optuna.samplers.RandomSampler(seed=0))

Using the exact same data, preprocessing steps, hyperparameter space, and objective function, we get around 0.548 in the F1-score evaluated in the validation data. We also get a dictionary consisting of the best set of hyperparameters as follows:

{'num_layers': 0,'optimizer': 'Adam','adam_lr': 0.05075826567070766,'epoch': 50}

After the model is trained with full data using the best set of hyperparameters, we get around 0.596 in F1-score when we test the final neural network model trained on the test data. Notice that although we...