JuliaDiff / JuliaDiff/ReverseDiff.jl

setindex! on TrackedArrays

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Dominant language
Julia
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393
Forks
60
Avg merge
18h 24m
Merged PRs (30d)
8

Description

Currently, TrackedArrays only support being overwritten in a few "blessed" situations (e.g. as inputs to specially-cased functions like A_mul_B!). I believe it may be possible to define record/propagation rules for setindex! on TrackedArray that will allow destructive indexing by preserving the pre-overwrite state in the tape.

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the issue's description of setindex! on TrackedArray and the existing destructive-update cases such as A_mul_B!. Investigate how pre-overwrite state is preserved in the tape and whether record/propagation rules can support indexing; done means destructive indexing works while maintaining correct tape propagation.

Written by the indexing model from the issue text.

Assessment

Tech stack
julia
Domain
backend
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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