JuliaArrays / JuliaArrays/StaticArrays.jl
Performance bug in compiling functions
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compile-time-performance
- Dominant language
- Julia
- Stars
- 844
- Forks
- 159
- Avg merge
- 3d 21h
- Merged PRs (30d)
- 3
Description
With Julia 1.7 and the StaticArrays v0.12.5:
julia> N = 14; m = SMatrix{N,N}(rand(N,N));
julia> x->x*m # works fine
#1 (generic function with 1 method)
julia> @time [x->x*g for g∈[m]]
3.018892 seconds (57.49 k allocations: 3.383 MiB, 100.06% compilation time)
1-element Vector{var"#20#22"{SMatrix{14, 14, Float64, 196}}}:
#20 (generic function with 1 method)
Why does it take 3 seconds? It seems to scale horribly, too: for N=10, I get 0.449260 seconds; for N=15, 5.230108 seconds; for N=16, 9.209356 seconds.
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First steps
- Read the whole issue, then the project's contributing guide.
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Research direction
Reproduce the example on Julia 1.7 with StaticArrays v0.12.5, starting with the @time [x->x*g for g∈[m]] case. Compare compilation time and allocations as N increases from 10 to 16, and trace the relevant StaticArrays compilation path. Done means identifying why this expression scales poorly and documenting or resolving the performance regression.
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
- Mostly clear
- Newbie friendliness
- 45/100