Book Image

Machine Learning Solutions

Book Image

Machine Learning Solutions

Overview of this book

Machine learning (ML) helps you find hidden insights from your data without the need for explicit programming. This book is your key to solving any kind of ML problem you might come across in your job. You’ll encounter a set of simple to complex problems while building ML models, and you'll not only resolve these problems, but you’ll also learn how to build projects based on each problem, with a practical approach and easy-to-follow examples. The book includes a wide range of applications: from analytics and NLP, to computer vision domains. Some of the applications you will be working on include stock price prediction, a recommendation engine, building a chat-bot, a facial expression recognition system, and many more. The problem examples we cover include identifying the right algorithm for your dataset and use cases, creating and labeling datasets, getting enough clean data to carry out processing, identifying outliers, overftting datasets, hyperparameter tuning, and more. Here, you'll also learn to make more timely and accurate predictions. In addition, you'll deal with more advanced use cases, such as building a gaming bot, building an extractive summarization tool for medical documents, and you'll also tackle the problems faced while building an ML model. By the end of this book, you'll be able to fine-tune your models as per your needs to deliver maximum productivity.
Table of Contents (19 chapters)
Machine Learning Solutions
Foreword
Contributors
Preface
Index

Understanding the testing matrix


In this section, we will understand the testing matrix and visualization approaches to evaluate the performance of the trained ML model. So let's understand both approaches, which are as follows:

  • The default testing matrix

  • The visualization approach

The default testing matrix

We are using the default score API of scikit-learn to check how well the ML is performing. In this application, the score function is the coefficient of the sum of the squared error. It is also called the coefficient of R2, which is defined by the following equation:

Here, u indicates the residual sum of squares. The equation for u is as follows:

The variable v indicates the total sum of squares. The equation for v is as follows:

The best possible score is 1.0, and it can be a negative score as well. A negative score indicates that the trained model can be arbitrarily worse. A constant model that always predicts the expected value for label y, disregarding the input features, will produce an...