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)

Kernel methods


Type inference in Julia primarily works by inspecting the types of function parameters and identifying the type of the return value. This suggests that some type instability issues may be mitigated by breaking up a function into smaller functions. This can provide additional hints to the compiler, making more accurate type inferencing possible.

For an example of this, consider a contrived function that takes as input the "Int64" or "Float64" string and returns an array of 10 elements, the types of which correspond to the type name passed as the input argument. Functions such as this may arise when creating arrays based on user input or by reading a file in which the type of the output is determined at runtime. Take a look at the following:

     function string_zeros(s::AbstractString)
         x = Array(s=="Int64"?Int64:Float64, 1_000_000)
         for i in 1:length(x)
             x[i] = 0
         end
         return x
     end

We will benchmark this code to find an average...