Book Image

Simulation for Data Science with R

By : Matthias Templ
Book Image

Simulation for Data Science with R

By: Matthias Templ

Overview of this book

Data Science with R aims to teach you how to begin performing data science tasks by taking advantage of Rs powerful ecosystem of packages. R being the most widely used programming language when used with data science can be a powerful combination to solve complexities involved with varied data sets in the real world. The book will provide a computational and methodological framework for statistical simulation to the users. Through this book, you will get in grips with the software environment R. After getting to know the background of popular methods in the area of computational statistics, you will see some applications in R to better understand the methods as well as gaining experience of working with real-world data and real-world problems. This book helps uncover the large-scale patterns in complex systems where interdependencies and variation are critical. An effective simulation is driven by data generating processes that accurately reflect real physical populations. You will learn how to plan and structure a simulation project to aid in the decision-making process as well as the presentation of results. By the end of this book, you reader will get in touch with the software environment R. After getting background on popular methods in the area, you will see applications in R to better understand the methods as well as to gain experience when working on real-world data and real-world problems.
Table of Contents (18 chapters)
Simulation for Data Science with R
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Machine numbers and rounding problems


A computer cannot store any value of a continuous distribution exactly, and continuous values get discretized (rounded) on a fine scale. The rounding of values and storage of values as machine numbers should always be kept in mind; for most applications, this doesn't lead to any problems.

"Most" means "not always". Some examples are shown in the following topics that will leave most users without background knowledge in machine numbers perplexed and irritated.

As a motivating example, the following "bug'' report (software R) serves as an example:

From: [email protected]

To: [email protected]

Subject: error in function trunc

Date: Fri, Jul 2007 15:03:58 +0200 6 (CEST)

The following command will get a wrong result:

trunc (2.3 * 100)
## [1] 229

Answer Duncan Murdoch: That is the correct answer. 2.3 is not representable Exactly; The actual value used is slightly less.

Remark: trunc() is the largest integer in cutting a value off after the decimal...