Book Image

Julia High Performance

By : Avik Sengupta
Book Image

Julia High Performance

By: Avik Sengupta

Overview of this book

Julia is a high performance, high-level dynamic language designed to address the requirements of high-level numerical and scientific computing. Julia brings solutions to the complexities faced by developers while developing elegant and high performing code. Julia High Performance will take you on a journey to understand the performance characteristics of your Julia programs, and enables you to utilize the promise of near C levels of performance in Julia. You will learn to analyze and measure the performance of Julia code, understand how to avoid bottlenecks, and design your program for the highest possible performance. In this book, you will also see how Julia uses type information to achieve its performance goals, and how to use multuple dispatch to help the compiler to emit high performance machine code. Numbers and their arrays are obviously the key structures in scientific computing – you will see how Julia’s design makes them fast. The last chapter will give you a taste of Julia’s distributed computing capabilities.
Table of Contents (14 chapters)

Programming parallel tasks


The low-level facilities that we saw in the previous section are quite flexible and very powerful. However, they leave a lot to be desired in terms of ease of use. Julia, therefore, has built-in set of higher-level programming tools that make it much easier to write parallel code. We will discuss some of them in the next section.

@everywhere

The @everywhere macro is used to run the same code in all the processes in the cluster. This is useful to set up the environment to run the actual parallel computation later. The following code loads the Distributions package and calls the rand method on all the nodes simultaneously, as follows:

julia> @everywhere using Distributions

julia> @everywhere rand(Normal())

@spawn

The @spawn macro is a simpler way to run a function in a remote process without having to specify the remote node or having to work through ambiguous syntax. Take a look at the following code:

julia> a=@spawn randn(5,5)^2
RemoteRef{Channel{Any}}(2,1...