# \[Pre-ANN\] ARS.jl
**URL:** https://discourse.julialang.org/t/pre-ann-ars-jl/131766
**Category:** Package Announcements
**Tags:** package, announcement, distributions, sampling
**Created:** [August 21, 2025, 8:01pm UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766 "2025-08-21T20:01:03Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Eliassj](https://discourse.julialang.org/u/Eliassj)
#### Post date: [August 21, 2025, 8:01pm UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766/1 "2025-08-21T20:01:03Z")
Repo: [GitHub - Eliassj/ARS.jl](https://github.com/Eliassj/ARS.jl/)
Docs: [eliassj.github.io/ARS.jl/dev/](https://eliassj.github.io/ARS.jl/dev/)
While working on another project I found that AdaptiveRejectionSampling.jl, while very good in other ways, did not allow for other numeric types than `Float64` (I needed to use `BigFloat`). For this reason (and fun) I implemented another version without restriction on element types, configurable differentiation backend (through DifferentiationInterface.jl) and (seemingly) faster sampling with fewer allocations. However, ARS.jl currently requires the user to specify initial points and for the function to sample from to already be in its log-form in favor of simplicity and speed. Meanwhile, AdaptiveRejectionSampling.jl will try to find initial points and log-transform the function to be sampled from if not told otherwise.
## Benchmark against AdaptiveRejectionSampling.jl
```julia-auto
using ARS, AdaptiveRejectionSampling
using DifferentiationInterface, Distributions
using ForwardDiff
# Define function to sample from
f(x) = logpdf(Laplace(0., 0.5), x) + logpdf(Normal(0.0, 2.0), x)
#= ARS.jl =#
sam_ARS = ARS.ARSampler(ARS.Objective(f, AutoForwardDiff()), [-0.5, 0.5], (-Inf, Inf))
@be deepcopy(sam_ARS) ARS.sample!(_, 100000, true, 25) samples=100 evals=1
# Benchmark: 100 samples with 1 evaluation
# min 6.739 ms (17 allocs: 784.492 KiB)
# median 7.089 ms (20 allocs: 784.586 KiB)
# mean 7.367 ms (21.26 allocs: 785.465 KiB, 1.42% gc time)
# max 18.497 ms (29 allocs: 789.367 KiB, 59.08% gc time)
#= AdaptiveRejectionSampling.jl =#
sam_other = RejectionSampler(f, (-Inf, Inf), (-0.5, 0.5); logdensity=true, max_segments=25)
@be deepcopy(sam_other) run_sampler!(_, 100000) samples=100 evals=1 seconds=1000
# Benchmark: 100 samples with 1 evaluation
# min 32.249 ms (2201420 allocs: 37.416 MiB, 6.99% gc time)
# median 32.912 ms (2201734 allocs: 37.421 MiB, 9.80% gc time)
# mean 34.020 ms (2201755.93 allocs: 37.421 MiB, 10.80% gc time)
# max 50.222 ms (2202237 allocs: 37.429 MiB, 22.42% gc time)
```
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### Author:  [@rveltz](https://discourse.julialang.org/u/rveltz)
#### Post date: [August 22, 2025, 5:42am UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766/2 "2025-08-22T05:42:08Z")
great! The speed-up is massive.
Why did you create a new package and not PR `AdaptiveRejectionSampling.jl`?
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### Author:  [@adienes](https://discourse.julialang.org/u/adienes)
#### Post date: [August 22, 2025, 8:03am UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766/3 "2025-08-22T08:03:19Z")
interesting, thanks for sharing!
just to caution you in advance, it is likely that you will be asked to change the name rather than register it as `ARS.jl` (assuming you want to submit it to the General registry) just before you get too attached to that name ๐
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### Author:  [@nsajko](https://discourse.julialang.org/u/nsajko)
#### Post date: [August 22, 2025, 9:53am UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766/4 "2025-08-22T09:53:05Z")
> [@adienes](#):
>
> it is likely that you will be asked to change the name rather than register it as `ARS.jl` (assuming you want to submit it to the General registry)
Doc link: [Package naming rules](https://pkgdocs.julialang.org/v1/creating-packages/#Package-naming-rules)
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### Author:  [@Eliassj](https://discourse.julialang.org/u/Eliassj)
#### Post date: [August 22, 2025, 10:31am UTC](https://discourse.julialang.org/t/pre-ann-ars-jl/131766/5 "2025-08-22T10:31:08Z")
Certainly! The reason I havenโt registered it is mostly due to the name ๐ . I will look into a pull request to AdaptiveRejectionSampling.jl as it seems like the most logical option.