Book Image

Time Series Indexing

By : Mihalis Tsoukalos
Book Image

Time Series Indexing

By: Mihalis Tsoukalos

Overview of this book

Time series are everywhere, ranging from financial data and system metrics to weather stations and medical records. Being able to access, search, and compare time series data quickly is essential, and this comprehensive guide enables you to do just that by helping you explore SAX representation and the most effective time series index, iSAX. The book begins by teaching you about the implementation of SAX representation in Python as well as the iSAX index, along with the required theory sourced from academic research papers. The chapters are filled with figures and plots to help you follow the presented topics and understand key concepts easily. But what makes this book really great is that it contains the right amount of knowledge about time series indexing using the right amount of theory and practice so that you can work with time series and develop time series indexes successfully. Additionally, the presented code can be easily ported to any other modern programming language, such as Swift, Java, C, C++, Ruby, Kotlin, Go, Rust, and JavaScript. By the end of this book, you'll have learned how to harness the power of iSAX and SAX representation to efficiently index and analyze time series data and will be equipped to develop your own time series indexes and effectively work with time series data.
Table of Contents (11 chapters)

Updating the counting.py utility

Remember the counting.py utility from Chapter 2? In this section, we are going to update it and use it for some important tasks. We are not going to completely change the existing functionality or throw away all the existing code. We are going to build on the existing code of the counting.py utility, which is a great and productive way to develop new software.

The updated version of the utility can be used for the following tasks:

  • Seeing whether a time series can fit into an iSAX index. This computation is based on the existing functionality of counting.py combined with a test of whether the values of all dictionary entries are smaller than the threshold value.
  • Seeing whether a time series can fit into an iSAX index using more segments or by increasing the threshold. Again, this computation is based on the existing functionality of counting.py, which is enhanced with some extra computations and testing.
  • Seeing whether an iSAX index...