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https://github.com/terasakisatoshi/libcalcpi_juliac
`juliac` in action
https://github.com/terasakisatoshi/libcalcpi_juliac
julia julialang juliiac
Last synced: about 1 month ago
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`juliac` in action
- Host: GitHub
- URL: https://github.com/terasakisatoshi/libcalcpi_juliac
- Owner: terasakisatoshi
- License: mit
- Created: 2024-10-05T02:29:10.000Z (3 months ago)
- Default Branch: main
- Last Pushed: 2024-11-18T22:49:07.000Z (about 1 month ago)
- Last Synced: 2024-11-18T23:44:05.449Z (about 1 month ago)
- Topics: julia, julialang, juliiac
- Language: Makefile
- Homepage:
- Size: 9.77 KB
- Stars: 7
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# [libcalcpi_juliac](https://github.com/terasakisatoshi/libcalcpi_juliac)
## Description
[This repository libcalcpi_juliac](https://github.com/terasakisatoshi/libcalcpi_juliac) provides an example of how to use `juliac` that offers a more traditional, gcc-like command-line interface for compiling Julia programs. See JuliaHub's blog post [New Ways to Compile Julia
](https://info.juliahub.com/blog/new-ways-to-compile-julia-blog) for more information about `juliac`.
This repository tries to compile the following Julia function named `jlcalcpi` which returns the approximate number of `π = 3.1415926535897...`.
```julia
function jlcalcpi(N)
cnt = 0
for a = 1:N, b = 1:N
cnt += ifelse(gcd(a, b) == 1, 1, 0)
end
prob = cnt / N / N
return √(6 / prob)
end
Base.@ccallable function calcpi(N::Cint)::Cdouble
jlcalcpi(N)
end
```
## TL;DR
```sh
make && ./a.out
```
## Usage
### Install Julia
Install Julia using [juliaup](https://github.com/JuliaLang/juliaup)
```sh
$ curl -fsSL https://install.julialang.org | sh -- --yes
```
### Download `juliac`
Run `make setup` to add nightly channel, download `juliac.jl` and `juliac-buildscript.jl`
```sh
$ ls
Makefile README.md libcalcpi.jl main.c
$ make setup
```
Then we have:
```sh
$ ls
Makefile juliac-buildscript.jl libcalcpi.jl
README.md juliac.jl main.c
```
### Build shared library and executable
```sh
$ make
Building... shared library
julia +nightly juliac.jl --output-lib libcalcpi.dylib --compile-ccallable --trim libcalcpi.jl
ld: warning: ignoring duplicate libraries: '-ljulia'
ld: warning: reexported library with install name '@rpath/libunwind.1.dylib' found at '/Users/terasakisatoshi/.julia/juliaup/julia-nightly/lib/julia/libunwind.1.0.dylib' couldn't be matched with any parent library and will be linked directly
Done
Building entrypoint
gcc -L./ -lcalcpi main.c -o a.out
```
We can use the `calcpi` function from C. This function corresponds to the following implementation in `libcalcpi.jl`:
```julia
Base.@ccallable function calcpi(N::Cint)::Cdouble
jlcalcpi(N)
end
```
### Run `./a.out`
```sh
$ ./a.out 10
3.0860669992418384
$ ./a.out 100
3.1395974980055170
$ ./a.out 1000
3.1404153403809061
$ ./a.out 10000 # default value
3.1415342390166292
$ ./a.out
3.1415342390166292
```
## Acknowledgment
[This comment by @jbytecode in the Julia Discourse thread 'Where is Juliac developed?'](https://discourse.julialang.org/t/where-is-juliac-developed/113004/32) was very helpful.