Book Image

Modern Time Series Forecasting with Python

By : Manu Joseph
5 (1)
Book Image

Modern Time Series Forecasting with Python

5 (1)
By: Manu Joseph

Overview of this book

We live in a serendipitous era where the explosion in the quantum of data collected and a renewed interest in data-driven techniques such as machine learning (ML), has changed the landscape of analytics, and with it, time series forecasting. This book, filled with industry-tested tips and tricks, takes you beyond commonly used classical statistical methods such as ARIMA and introduces to you the latest techniques from the world of ML. This is a comprehensive guide to analyzing, visualizing, and creating state-of-the-art forecasting systems, complete with common topics such as ML and deep learning (DL) as well as rarely touched-upon topics such as global forecasting models, cross-validation strategies, and forecast metrics. You’ll begin by exploring the basics of data handling, data visualization, and classical statistical methods before moving on to ML and DL models for time series forecasting. This book takes you on a hands-on journey in which you’ll develop state-of-the-art ML (linear regression to gradient-boosted trees) and DL (feed-forward neural networks, LSTMs, and transformers) models on a real-world dataset along with exploring practical topics such as interpretability. By the end of this book, you’ll be able to build world-class time series forecasting systems and tackle problems in the real world.
Table of Contents (26 chapters)
1
Part 1 – Getting Familiar with Time Series
6
Part 2 – Machine Learning for Time Series
13
Part 3 – Deep Learning for Time Series
20
Part 4 – Mechanics of Forecasting

Gated recurrent unit (GRU)

In 2014, Cho et al. proposed another variant of the RNN that has a much simpler structure than an LSTM, called a gated recurrent unit (GRU). The intuition behind this is similar to when we use a bunch of gates to regulate the information that flows through the cell, but a GRU eliminates the long-term memory component and uses just the hidden state to propagate information. So, instead of the memory cell becoming the gradient highway, the hidden state itself becomes the “gradient highway.” In keeping with the same notation convention we used in the previous section, let’s look at the updated equations for a GRU.

While we had three gates in an LSTM, we only have two in a GRU:

  • Reset gate: This gate decides how much of the previous hidden state will be considered as the candidate's hidden state of the current timestep. The equation for this is:
  • Update gate: The update gate decides how much of the previous hidden...