Hands-On Machine Learning with Scikit-Learn, Keras, and Tensorflow: Concepts, Tools, and Techniques to Build Intelligent Systems

by Aurélien Géron

This is counterintuitive: how can two points be so far apart when they both lie within the same unit hypercube? Well, there’s just plenty of space in high dimensions. As a result, high-dimensional datasets are at risk of being very sparse: most training instances are likely to be far away from each other.