Book Image

Advanced Machine Learning with R

By : Cory Lesmeister, Dr. Sunil Kumar Chinnamgari
Book Image

Advanced Machine Learning with R

By: Cory Lesmeister, Dr. Sunil Kumar Chinnamgari

Overview of this book

R is one of the most popular languages when it comes to exploring the mathematical side of machine learning and easily performing computational statistics. This Learning Path shows you how to leverage the R ecosystem to build efficient machine learning applications that carry out intelligent tasks within your organization. You’ll work through realistic projects such as building powerful machine learning models with ensembles to predict employee attrition. Next, you’ll explore different clustering techniques to segment customers using wholesale data and even apply TensorFlow and Keras-R for performing advanced computations. Each chapter will help you implement advanced machine learning algorithms using real-world examples. You’ll also be introduced to reinforcement learning along with its use cases and models. Finally, this Learning Path will provide you with a glimpse into how some of these black box models can be diagnosed and understood. By the end of this Learning Path, you’ll be equipped with the skills you need to deploy machine learning techniques in your own projects.
Table of Contents (30 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

K-nearest neighbors


In our previous efforts, we built models that had coefficients or, to put it in another way, parameter estimates for each of our included features. With KNN, we have no parameters as the learning method is so-called instance-based learning. In short, labeled examples (inputs and corresponding output labels) are stored, and no action is taken until a new input pattern demands an output value (Battiti and Brunato, 2014, p. 11). This method is commonly called lazy learning, as no specific model parameters are produced. The train instances themselves represent the knowledge. For the prediction of any new instance (a new data point), the training data is searched for an instance that most resembles the new instance in question. KNN does this for a classification problem by looking at the closest points—the nearest neighbors—to determine the proper class. The k comes into play by deciding how many neighbors should be examined by the algorithm, so if k=5, it will consider the...