mcabbott / mcabbott/TensorCast.jl
Slicing an array produces `Vector{<:SubArray}`, hence allocates
Open
Nobody has claimed this yet.
- Dominant language
- Julia
- Stars
- 142
- Forks
- 12
- PR merge metrics
- No merged PRs in 30d
Description
using TensorCast, ArraysOfArrays
A = rand(3,3,10000)
@btime out = nestedview($A, 2)
1.587 ns (0 allocations: 0 bytes)
@btime @cast b[i][j,k] := $A[i,j,k]
99.926 ns (6 allocations: 304 bytes)
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the reported @btime comparisons for nestedview($A, 2) and @cast b[i][j,k] := $A[i,j,k] using the shown TensorCast and ArraysOfArrays setup. Investigate why the @cast form produces Vector{<:SubArray} and allocations; done means the reported slicing operation no longer incurs those allocations while preserving its result.
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
- 38/100