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

Tasks


Julia has a built-in system for running tasks, which are, in general, known as coroutines. With this, a computation that generates values into a Channel (with a put! function) can be suspended as a task, while a consumer task can pick up the values (with a take! function). This is similar to the yield keyword in Python.

As a concrete example, let's take a look at a fib_producer function that calculates the first 10 Fibonacci numbers (refer to the Recursive functions section in Chapter 3, Functions), but it doesn't return the numbers, it produces them:

# code in Chapter 4\tasks.jl  
 function fib_producer(c::Channel) 
        a, b = (0, 1) 
        for i = 1:10 
            put!(c, b) 
            a, b = (b, a + b) 
        end 
    end 

Construct a Channel by providing this function as an argument:

chnl = Channel(fib_producer)

The task's state is now runnable. To get the Fibonacci numbers, start consuming them with take! until Channel is closed, and the task is finished (state is :done...