Book Image

Mastering Julia - Second Edition

By : Malcolm Sherrington
Book Image

Mastering Julia - Second Edition

By: Malcolm Sherrington

Overview of this book

Julia is a well-constructed programming language which was designed for fast execution speed by using just-in-time LLVM compilation techniques, thus eliminating the classic problem of performing analysis in one language and translating it for performance in a second. This book is a primer on Julia’s approach to a wide variety of topics such as scientific computing, statistics, machine learning, simulation, graphics, and distributed computing. Starting off with a refresher on installing and running Julia on different platforms, you’ll quickly get to grips with the core concepts and delve into a discussion on how to use Julia with various code editors and interactive development environments (IDEs). As you progress, you’ll see how data works through simple statistics and analytics and discover Julia's speed, its real strength, which makes it particularly useful in highly intensive computing tasks. You’ll also and observe how Julia can cooperate with external processes to enhance graphics and data visualization. Finally, you will explore metaprogramming and learn how it adds great power to the language and establish networking and distributed computing with Julia. By the end of this book, you’ll be confident in using Julia as part of your existing skill set.
Table of Contents (14 chapters)

C and Fortran

Julia has a single ccall() function that will run a routine compiled and bundled into a shared object library.

The call has the form

ccall((func,libr),ret_type,(arg1_type,arg2_type, …),arg1, arg2, …)

where the object code for the func function is present in the libr shared library and returns a value of ret_type, followed by an optional tuple of arguments and the actual argument values.

If the library name is omitted, then it defaults to the default Julia library, libjulia, and in this case, the first argument is now specified as a string rather than a tuple.

If necessary, Julia can “find” the library, which usually requires adding it to a library on the LD_LIBRARY_PATH load library path or modifying the latter to contain a new directory.

Note

As of version 1.0+, ccall() may have a function pointer as a first argument.

An alternate, more convenient form, is to use the @ccall macro:

@ccall lib.fun(arg1::arg1_type,arg2...