Book Image

Julia 1.0 Programming. - Second Edition

By : Ivo Balbaert
Book Image

Julia 1.0 Programming. - Second Edition

By: Ivo Balbaert

Overview of this book

The release of Julia 1.0 is now ready to change the technical world by combining the high productivity and ease of use of Python and R with the lightning-fast speed of C++. Julia 1.0 programming gives you a head start in tackling your numerical and data problems. You will begin by learning how to set up a running Julia platform, before exploring its various built-in types. With the help of practical examples, this book walks you through two important collection types: arrays and matrices. In addition to this, you will be taken through how type conversions and promotions work. In the course of the book, you will be introduced to the homo-iconicity and metaprogramming concepts in Julia. You will understand how Julia provides different ways to interact with an operating system, as well as other languages, and then you'll discover what macros are. Once you have grasped the basics, you’ll study what makes Julia suitable for numerical and scientific computing, and learn about the features provided by Julia. By the end of this book, you will also have learned how to run external programs. This book covers all you need to know about Julia in order to leverage its high speed and efficiency for your applications.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Integers


Julia offers support for integer numbers ranging from types Int8 to Int128, with 8 to 128 representing the number of bits used, and with unsigned variants with a U prefix, such as UInt8. The default type (which can also be used as Int) is Int32 or Int64, depending on the target machine architecture. The bit width is given by the Sys.WORD_SIZE variable. The number of bits used by the integer affects the maximum and minimum value this integer can have. The minimum and maximum values are given by the typemin() and typemax() functions, respectively; for example, typemax(Int16) returns 32767.

If you try to store a number larger than that allowed by typemax, overflow occurs. For example, note the following:

julia> typemax(Int)9223372036854775807 # might be different on 32 bit platformjulia> ans + 1-9223372036854775808

Overflow checking is not automatic, so an explicit check (for example, the result has the wrong sign) is needed when this can occur. Integers can also be written in binary...