Book Image

Machine Learning with Swift

By : Jojo Moolayil, Alexander Sosnovshchenko, Oleksandr Baiev
Book Image

Machine Learning with Swift

By: Jojo Moolayil, Alexander Sosnovshchenko, Oleksandr Baiev

Overview of this book

Machine learning as a field promises to bring increased intelligence to the software by helping us learn and analyse information efficiently and discover certain patterns that humans cannot. This book will be your guide as you embark on an exciting journey in machine learning using the popular Swift language. We’ll start with machine learning basics in the first part of the book to develop a lasting intuition about fundamental machine learning concepts. We explore various supervised and unsupervised statistical learning techniques and how to implement them in Swift, while the third section walks you through deep learning techniques with the help of typical real-world cases. In the last section, we will dive into some hard core topics such as model compression, GPU acceleration and provide some recommendations to avoid common mistakes during machine learning application development. By the end of the book, you'll be able to develop intelligent applications written in Swift that can learn for themselves.
Table of Contents (18 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Understanding the KNN algorithm


To recognize different types of motion activities, we will train the KNN classifier. The idea of the method is to find k training samples closest to the sample with an unknown label, and predict the label as a most frequent class among those k. That's it:

Figure 3.5: KNN classification algorithm. The new data point marked with ? gets classified based on the classes of its neighbors.

Note

Note how the choice of neighbor number affects the result of classification.

In fact, the algorithm is so simple, that it's tempting to formulate it in more complicated terms. Let's do it. The secret sauce of a KNN is a distance metric: function, which defines how close to each other two samples are. We have discussed several of them already: Euclidean, Manhattan, Minkowski, edit distance, and DTW. Following the terminology, samples are points in some n-dimensional space, where n equals to the number of features in each sample. This space is called feature space, and samples are...