#### Overview of this book

Machine Learning for Finance explores new advances in machine learning and shows how they can be applied across the financial sector, including insurance, transactions, and lending. This book explains the concepts and algorithms behind the main machine learning techniques and provides example Python code for implementing the models yourself. The book is based on Jannes Klaas’ experience of running machine learning training courses for financial professionals. Rather than providing ready-made financial algorithms, the book focuses on advanced machine learning concepts and ideas that can be applied in a wide variety of ways. The book systematically explains how machine learning works on structured data, text, images, and time series. You'll cover generative adversarial learning, reinforcement learning, debugging, and launching machine learning products. Later chapters will discuss how to fight bias in machine learning. The book ends with an exploration of Bayesian inference and probabilistic programming.
Machine Learning for Finance
Contributors
Preface
Other Books You May Enjoy
Free Chapter
Applying Machine Learning to Structured Data
Utilizing Computer Vision
Understanding Time Series
Parsing Textual Data with Natural Language Processing
Using Generative Models
Reinforcement Learning for Financial Markets
Privacy, Debugging, and Launching Your Products
Fighting Bias
Bayesian Inference and Probabilistic Programming
Index

## Evolutionary strategies and genetic algorithms

Recently, a decades-old optimization algorithm for reinforcement learning algorithms has come back into fashion. Evolutionary strategies (ES) are much simpler than Q-learning or A2C.

Instead of training one model through backpropagation, in ES we create a population of models by adding random noise to the weights of the original model. We then let each model run in the environment and evaluate its performance. The new model is the performance-weighted average of all the models.

In the following diagram, you can see a visualization of how evolution strategies work:

Evolutionary strategy

To get a better grip on how this works, consider the following example. We want to find a vector that minimizes the mean squared error to a solution vector. The learner is not given the solution, but only the total error as a reward signal:

```solution = np.array([0.5, 0.1, -0.3])
def f(w):
reward = -np.sum(np.square(solution - w))
return reward```