JuliaArrays / JuliaArrays/BlockArrays.jl
`Diagonal(BlockVector)[Block(i, i)]` is not `Diagonal`
Open
Nobody has claimed this yet.
- Dominant language
- Julia
- Stars
- 254
- Forks
- 39
- PR merge metrics
- No merged PRs in 30d
Description
For example:
julia> using BlockArrays
julia> d = Diagonal(BlockedVector([1, 2, 3, 4], [2, 2]))
4×4 Diagonal{Int64, BlockedVector{Int64, Vector{Int64}, Tuple{BlockedOneTo{Int64, Vector{Int64}}}}} with indices BlockedOneTo([2, 4])×BlockedOneTo([2, 4]):
1 ⋅ │ ⋅ ⋅
⋅ 2 │ ⋅ ⋅
──────┼──────
⋅ ⋅ │ 3 ⋅
⋅ ⋅ │ ⋅ 4
julia> d[Block(1, 1)]
2×2 Matrix{Int64}:
1 0
0 2
Shows up in #426.
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 reproducing the Diagonal(BlockedVector(...)) example from the issue and inspect the block-indexing path for d[Block(1, 1)]. Trace why that access returns a matrix instead of a Diagonal, then add or update a regression test showing the expected diagonal result.
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
- 35/100