Book Image

Machine Learning Algorithms - Second Edition

Book Image

Machine Learning Algorithms - Second Edition

Overview of this book

Machine learning has gained tremendous popularity for its powerful and fast predictions with large datasets. However, the true forces behind its powerful output are the complex algorithms involving substantial statistical analysis that churn large datasets and generate substantial insight. This second edition of Machine Learning Algorithms walks you through prominent development outcomes that have taken place relating to machine learning algorithms, which constitute major contributions to the machine learning process and help you to strengthen and master statistical interpretation across the areas of supervised, semi-supervised, and reinforcement learning. Once the core concepts of an algorithm have been covered, you’ll explore real-world examples based on the most diffused libraries, such as scikit-learn, NLTK, TensorFlow, and Keras. You will discover new topics such as principal component analysis (PCA), independent component analysis (ICA), Bayesian regression, discriminant analysis, advanced clustering, and gaussian mixture. By the end of this book, you will have studied machine learning algorithms and be able to put them into production to make your machine learning applications more innovative.
Table of Contents (19 chapters)

SVMs with scikit-learn

To allow the model to have a more flexible separating hyperplane, all scikit-learn implementations are based on a simple variant that includes so-called slack variables ζi in the function to minimize (sometimes called C-Support Vector Machines):

In this case, the constraints become the following:

The introduction of slack variables allows us to create a flexible margin so that some vectors belonging to a class can also be found in the opposite part of the hyperspace and can be included in the model training. The strength of this flexibility can be set using the C parameter. Small values (close to zero) bring about very hard margins, while values greater than or equal to 1 allow more and more flexibility (while also increasing the misclassification rate). Equivalently, when C → 0, the number of support vectors is minimized, while larger C values...