JuliaCall for Seamless Integration of R and Julia

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Package JuliaCall is an R interface to Julia, which is a high-level, high-performance dynamic programming language for numerical computing, see https://julialang.org/ for more information. Below is an image for Mandelbrot set. JuliaCall brings more than 100 times speedup of the calculation! See https://github.com/Non-Contradiction/JuliaCall/tree/master/example/mandelbrot for more information.

Installation

JuliaCall is on CRAN now! To use package JuliaCall, you first have to install Julia on your computer, you can download a generic binary from https://julialang.org/downloads/ and add it to your path, and then you can install JuliaCall just like any other R packages by

install.packages("JuliaCall")

You can get the development version of JuliaCall by

devtools::install_github("Non-Contradiction/JuliaCall")

Basic Usage

library(JuliaCall)

## Do initial setup

julia <- julia_setup()
#> Julia version 0.6.2 at location /Applications/Julia-0.6.app/Contents/Resources/julia/bin will be used.
#> Julia initiation...
#> Finish Julia initiation.
#> Loading setup script for JuliaCall...
#> Finish loading setup script for JuliaCall.

## If you want to use a julia at a specific location, you could do the following:
## julia_setup(JULIA_HOME = "the folder that contains julia binary"), 
## or you can set JULIA_HOME in command line environment or use `options(...)`

## Different ways for using Julia to calculate sqrt(2)

# julia$command("a = sqrt(2);"); julia$eval("a")
julia_command("a = sqrt(2);"); julia_eval("a")
#> [1] 1.414214
julia_eval("sqrt(2)")
#> [1] 1.414214
julia_call("sqrt", 2)
#> [1] 1.414214
julia_eval("sqrt")(2)
#> [1] 1.414214
julia_assign("x", sqrt(2)); julia_eval("x")
#> [1] 1.414214
julia_assign("rsqrt", sqrt); julia_call("rsqrt", 2)
#> [1] 1.414214
2 %>J% sqrt
#> [1] 1.414214

## You can use `julia$exists` as `exists` in R to test
## whether a function or name exists in Julia or not

julia_exists("sqrt")
#> [1] TRUE
julia_exists("c")
#> [1] FALSE

## You can use `julia$help` to get help for Julia functions

julia_help("sqrt")
#> ```
#> sqrt(x)
#> ```
#> 
#> Return $\sqrt{x}$. Throws [`DomainError`](@ref) for negative [`Real`](@ref) arguments. Use complex negative arguments instead. The prefix operator `√` is equivalent to `sqrt`.

## Functions related to installing and using Julia packages

julia_install_package("Optim")
julia_install_package_if_needed("Optim")
julia_installed_package("Optim")
#> [1] "0.14.1"
julia_library("Optim")

Trouble Shooting and Way to Get Help

Julia is not found

Make sure the Julia installation is correct. JuliaCall is able to find Julia on PATH, and there are three ways for JuliaCall to find Julia not on PATH.

How to Get Help

julia_help("sqrt")
#> ```
#> sqrt(x)
#> ```
#> 
#> Return $\sqrt{x}$. Throws [`DomainError`](@ref) for negative [`Real`](@ref) arguments. Use complex negative arguments instead. The prefix operator `√` is equivalent to `sqrt`.

JuliaCall for R Package Developers

If you are interested in developing an R package which is an interface for a Julia package, JuliaCall is an ideal choice for that!

Basically you only need to find the Julia function or Julia module you want to have in R and then just using the module and call the function. Several examples are:

If you have any issues in developing an R package using JuliaCall, you may report it using the link: https://github.com/Non-Contradiction/JuliaCall/issues/new. Or email me at lch34677@gmail.com or cxl508@psu.edu.

Suggestion and Issue Reporting

JuliaCall is under active development now. Any suggestion or issue reporting is welcome! You may report it using the link: https://github.com/Non-Contradiction/JuliaCall/issues/new. Or email me at lch34677@gmail.com or cxl508@psu.edu.

And if you encounter some issues which crash R or RStudio, then you may have met segfault errors. I am very sorry. And I am trying my best to remove errors like that. It will be much appreciated if you can

Interfaces between R and Julia