Setup Julia

Julia is a high-level, high-performance, dynamic programming language. From the designing stage, Julia is intended to address the needs of high-performance numerical analysis and computational science, without the typical need of separate compilation to be fast, while also being effective for general-purpose programming, web use or as a specification language. Julia is also a free and open-source language, with a large community and a rich ecosystem.

We will devlve deeper into Julia later in the chapter. For now, we will just install Julia and setup the environment.

Step 1: Installing Julia

For Linux/Mac users, please open a terminal and type the following command to install Julia with juliaup. Juliaup is a tool to manage Julia versions and installations. It allows you to install multiple versions of Julia and switch between them easily.

curl -fsSL https://install.julialang.org | sh # Linux and macOS

For Windows users, please open execute the following command in a cmd,

winget install julia -s msstore # Windows

You can also install Juliaup directly from Windows Store.

For users suffering from the slow download speed

Network connectivity can be an issue for some users, especially for those who are in China. You may need to specify another server for installing Juliaup and Julia packages. To do so, execute the following command in your terminal before running the script above.

Linux and macOS

export JULIAUP_SERVER=https://mirror.nju.edu.cn/julia-releases/ # Linux & macOS
export JULIA_PKG_SERVER=https://mirrors.nju.edu.cn/julia

Windows

$env:JULIAUP_SERVER="https://mirror.nju.edu.cn/julia-releases/" # Windows
$env:JULIA_PKG_SERVER="https://mirrors.nju.edu.cn/julia"

An alternative approach is downloading the corresponding Julia binary from the Nanjing university mirror website. After installing the binary, please set the Julia binary path properly if you want to start a Julia REPL from a terminal, check this manual page to learn more.

Installing Julia

To verify that Julia is installed, please open a new terminal and run the following command in your terminal.

julia

It should start a Julia REPL(Read-Eval-Print-Loop) session.
If you wish to install a specific version of Julia, please refer to the documentation.

Step 2: Package Management

Julia has a mature eco-system for scientific computing.
Pkg is the built-in package manager for Julia.
To enter the package manager, press ] in the REPL.

PackageMangement

The environment is indicated by the (@v1.9).
To add a package, type add <package name>.
To exit the package manager press backspace key
Read More

Step 3. Configure the startup file

First create a new file ~/.julia/config/startup.jl by executing the following commands

mkdir -p ~/.julia/config
echo 'try
    using Revise
catch e
    @warn "fail to load Revise."
end' > ~/.julia/config/startup.jl

The contents in the startup file is executed immediately after you open a new Julia session.

Then you need to install Revise, which is an Julia package that can greatly improve the using experience of Julia. To install Revise, open Julia REPL and type

julia> using Pkg; Pkg.add("Revise")

If you don't know about startup.jl and where to find it, here is a good place for further information.

More Packages

You may find more Julia packages here.

As a final step, please verify your Julia configuration by openning a Julia REPL and type

julia> versioninfo()
Julia Version 1.9.2
Commit e4ee485e909 (2023-07-05 09:39 UTC)
Platform Info:
  OS: macOS (arm64-apple-darwin22.4.0)
  CPU: 10 × Apple M2 Pro
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-14.0.6 (ORCJIT, apple-m1)
  Threads: 1 on 6 virtual cores
Environment:
  JULIA_NUM_THREADS = 1
  JULIA_PROJECT = @.
  JULIA_PKG_SERVER = http://cn-southeast.pkg.juliacn.com/

Step 4. Download an editor: VSCode

Install VSCode by downloading the correct binary for your platform from here. Open VSCode and open the Extensions tab on the left side-bar of the window, search Julia and install the most popular extension: julia-vscode

The four modes of Julia REPL

A Julia REPL has four modes,

Julian mode is the default mode that can interpret your Julia code.
Shell mode is the mode that you can run shell commands. Press ; in the Julian mode and type

shell> date
Sun Nov  6 10:50:21 PM CST 2022

To return to the Julian mode, type the Backspace key.

Package mode is the mode that you can manage packages. Press ] in the Julian mode and type

(@v1.8) pkg> st
Status `~/.julia/environments/v1.8/Project.toml`
  [295af30f] Revise v3.4.0

To return to the Julian mode, type the Backspace key.

Help mode is the mode that you can access the docstrings of functions. Press ? in the Julian mode and type

help> sum
... docstring for sum ...

To return to the Julian mode, type the Backspace key.