JuliaArrays / JuliaArrays/StaticArrays.jl
Strange behaviour with `@inline`d functions and `StaticArrays`
Nobody has claimed this yet.
- Dominant language
- Julia
- Stars
- 844
- Forks
- 159
- Avg merge
- 3d 21h
- Merged PRs (30d)
- 3
Description
Consider the following code
using StaticArrays
@inline fun(A, x::SVector) = A * x
@inline fun(A, x::Vector) = fun(A, SVector{2}(x))
A = MMatrix{1, 2}(0.2582836768895444, -0.7450543662661093)
x = [0.9349412115157324, 0.01823374719995763]
fun(A, x) == fun(A, SVector{2}(x))
The last equality does not hold on my machine (Julia 1.10.0-beta3 macOS x86, StaticArrays v1.6.5).
If fun(A, x::SVector) = A * x is no longer inline then the equality holds.
It also works if A is a SMatrix.
Since this works on Julia 1.9 it may be an upstream bug, but I posted it here because I cannot reproduce it without using StaticArrays.
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by running the reproducer in the issue with Julia 1.10.0-beta3 and StaticArrays v1.6.5, then compare it with Julia 1.9. Check the behavior when the SVector method is not inlined and when A is an SMatrix. Done means identifying the source of the differing equality result and determining whether the fix belongs in StaticArrays.jl or upstream Julia.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- julia
- Domain
- performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100