Book Image

Scala for Machine Learning

By : Patrick R. Nicolas
Book Image

Scala for Machine Learning

By: Patrick R. Nicolas

Overview of this book

Table of Contents (20 chapters)
Scala for Machine Learning
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Numerical optimization


This section briefly introduces the different optimization algorithms that can be applied to minimize the loss function, with or without a penalty term. These algorithms are described in more detail in the Summary of optimization techniques section in the Appendix A, Basic Concepts.

First, let's define the least squares problem. The minimization of the loss function consists of nullifying the first order derivatives, which in turn generates a system of D equations (also known as the gradient equations), D being the number of regression weights (parameters). The weights are iteratively computed by solving the system of equations using a numerical optimization algorithm.

Note

M10: The definition of the least squares-based loss function for residual ri, weights w, a model f, input data xi, and expected values yi is as follows:

M10: The generation of gradient equations with a Jacobian J matrix (refer to the Mathematics section in the Appendix A, Basic Concepts) after minimization...