JuliaArrays / JuliaArrays/StaticArrays.jl
`kron(::SMatrix, ::SDiagonal)` doesn't produce an `SMatrix`
Open
Nobody has claimed this yet.
- Dominant language
- Julia
- Stars
- 844
- Forks
- 159
- Avg merge
- 3d 21h
- Merged PRs (30d)
- 3
Description
I noticed the following (c.f. #257)
julia> using StaticArrays
julia> A = @SMatrix rand(3, 3)
3×3 SMatrix{3, 3, Float64, 9} with indices SOneTo(3)×SOneTo(3):
0.096179 0.904208 0.721372
0.329266 0.80936 0.112793
0.607664 0.412918 0.816508
julia> B = @SMatrix rand(3, 3)
3×3 SMatrix{3, 3, Float64, 9} with indices SOneTo(3)×SOneTo(3):
0.545279 0.442201 0.237385
0.26991 0.755759 0.917111
0.618612 0.246417 0.305401
julia> D = SDiagonal(1,1,1)
3×3 LinearAlgebra.Diagonal{Int64, SVector{3, Int64}} with indices SOneTo(3)×SOneTo(3):
1 ⋅ ⋅
⋅ 1 ⋅
⋅ ⋅ 1
julia> kron(A, B) |> typeof
SMatrix{9, 9, Float64, 81} (alias for SArray{Tuple{9, 9}, Float64, 2, 81})
julia> kron(A, D) |> typeof
Matrix{Float64} (alias for Array{Float64, 2})
I would expect that the return type is a SMatrix, like above.
Here is what I'm running
julia> versioninfo()
Julia Version 1.9.0
Commit 8e630552924 (2023-05-07 11:25 UTC)
Platform Info:
OS: macOS (arm64-apple-darwin22.4.0)
CPU: 10 × Apple M1 Pro
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-14.0.6 (ORCJIT, apple-m1)
Threads: 8 on 8 virtual cores
Environment:
JULIA_NUM_THREADS = auto
JULIA_IMAGE_THREADS = 1
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
Reproduce the reported kron(A, D) case with an SMatrix and SDiagonal, then trace the kron dispatch and related StaticArrays methods. Compare its result with kron(A, B); done means the diagonal case returns an SMatrix and a regression test covers the reported behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- julia
- Domain
- data
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100