JuliaCall: Seamless Integration Between R and Julia.

JuliaCall provides you with functions to call Julia functions and to use Julia packages as easy as possible.

Examples

 ## The examples are quite time consuming

  ## Do initiation for JuliaCall

  julia <- julia_setup()
#> Julia version 1.0.3 at location /Applications/Julia-1.0.app/Contents/Resources/julia/bin will be used.
#> Loading setup script for JuliaCall...
#> Finish loading setup script for JuliaCall.

  ## Different ways for calculating `sqrt(2)`

  # julia$command("a = sqrt(2)"); julia$eval("a")
  julia_command("a = sqrt(2)"); julia_eval("a")
#> 1.4142135623730951
#>   
#> [1] 1.414214

  # julia$eval("sqrt(2)")
  julia_eval("sqrt(2)")
#> [1] 1.414214

  # julia$call("sqrt", 2)
  julia_call("sqrt", 2)
#> [1] 1.414214

  # julia$eval("sqrt")(2)
  julia_eval("sqrt")(2)
#> [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")
  julia_exists("sqrt")
#> [1] TRUE

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

  # julia$help("sqrt")
  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`.
#> 
#> # Examples
#> 
#> ```jldoctest; filter = r"Stacktrace:(\n \[[0-9]+\].*)*"
#> julia> sqrt(big(81))
#> 9.0
#> 
#> julia> sqrt(big(-81))
#> ERROR: DomainError with -8.1e+01:
#> NaN result for non-NaN input.
#> Stacktrace:
#>  [1] sqrt(::BigFloat) at ./mpfr.jl:501
#> [...]
#> 
#> julia> sqrt(big(complex(-81)))
#> 0.0 + 9.0im
#> ```
#> 
#> ```
#> sqrt(A::AbstractMatrix)
#> ```
#> 
#> If `A` has no negative real eigenvalues, compute the principal matrix square root of `A`, that is the unique matrix $X$ with eigenvalues having positive real part such that $X^2 = A$. Otherwise, a nonprincipal square root is returned.
#> 
#> If `A` is symmetric or Hermitian, its eigendecomposition ([`eigen`](@ref)) is used to compute the square root. Otherwise, the square root is determined by means of the Björck-Hammarling method [^BH83], which computes the complex Schur form ([`schur`](@ref)) and then the complex square root of the triangular factor.
#> 
#> [^BH83]: Åke Björck and Sven Hammarling, "A Schur method for the square root of a matrix", Linear Algebra and its Applications, 52-53, 1983, 127-140. [doi:10.1016/0024-3795(83)80010-X](https://doi.org/10.1016/0024-3795(83)80010-X)
#> 
#> # Examples
#> 
#> ```jldoctest
#> julia> A = [4 0; 0 4]
#> 2×2 Array{Int64,2}:
#>  4  0
#>  0  4
#> 
#> julia> sqrt(A)
#> 2×2 Array{Float64,2}:
#>  2.0  0.0
#>  0.0  2.0
#> ```

  ## You can install and use Julia packages through JuliaCall

  # julia$install_package("Optim")
  julia_install_package("Optim")

  # julia$install_package_if_needed("Optim")
  julia_install_package_if_needed("Optim")

  # julia$installed_package("Optim")
  julia_installed_package("Optim")
#> [1] "0.18.1"

  # julia$library("Optim")
  julia_library("Optim")