JuliaDiff / JuliaDiff/ChainRulesCore.jl
`tangent * tangent` and `dot(tangent, tangent)` can return tangents.
Nobody has claimed this yet.
- Dominant language
- Julia
- Stars
- 267
- Forks
- 66
- PR merge metrics
- No merged PRs in 30d
Description
I noticed that there are methods of * and dot for the AbstractZero types that work like
Base.:*(::NoTangent, ::NoTangent) = NoTangent()
LinearAlgebra.dot(::NoTangent, ::ZeroTangent) = ZeroTangent()
However, if both arguments are tangents,
*should not be defined.dotshould return a real number, not another tangent.
In my understanding, code that relies on such nonlinear tangent to tangent operations cannot be correct, so it may be worthwhile to remove such methods.
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 locating the AbstractZero definitions for * and dot, including the NoTangent and ZeroTangent cases shown in the issue. Compare the behavior when both arguments are tangents and check the surrounding tests. Done means tangent-to-tangent * is no longer defined and tangent-to-tangent dot returns a real number.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- julia
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100