Julia-related procedures

In this section, we will show you a few things related specifically to running code reproducibly with Julia. For more general debugging tips for Julia and other computer languages, see our wiki.

The following instructions are primarily for Linux.

You may need to use Conda on our Windows systems.

Managing multiple Julia versions

Julia has a native version manager. Follow instructions at JuliaLang/juliaup to install it - it will be installed in your personal directory (so is not shared). Then, to add a particular Julia version,

juliaup add 1.9.2
juliaup default 1.9.2

and your next call to Julia will launch 1.9.2.

Julia is picky about how environments are passed to workers

julia --project=julia16 -p 4

should start with the project installed in folder julia16 and 4 worker processes. In fact, the worker processes ignore the project packages, and the whole thing fails (see this link).

Workaround:

export JULIA_PROJECT=julia16
julia -p 4

seems to work.

Importing someone else’s Julia environment

An author using Julia may have included Project.toml and/or Manifest.toml, which specify Julia version and dependencies. To activate this environment (one time action):

julia --project=project/path -e 'using Pkg; Pkg.instantiate()'

where project/path contains Project.toml and Manifest.toml (typically, the code directory). (more information here).

Alternatively, you can add

using Pkg
Pkg.instantiate()

at the top of the main file (if there is one), and invoke this

export JULIA_PROJECT=project/path
julia -p 4 main.jl

In many cases, project/path will be ., i.e., main.jl and the TOML files are in the same directory.