JuliaDiff/ChainRulesCore.jl

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AD-backend agnostic system defining custom forward and reverse mode rules. This is the light weight core to allow you to define rules for your functions in your packages, without depending on any particular AD system.

Stars: 267
Forks: 66
Open beginner issues: 0
Indexed issues: 112

Dominant language: Julia
License: No license data
Last GitHub push: Jun 22, 2026
Latest indexed: Sep 18, 2026
Contributing guide: No contributing guide
Code of conduct: No code of conduct
Beginner labels: good first issue help wanted
PR merge metrics: No merged PRs in 30d

Beginner friendly Everything

Open All

112 issues indexed so far

variable scope of `@thunk` Open

Difficulty 4/5 3-5 days Newbie friendliness 32/100

JuliaDiff/ChainRulesCore.jl#684 · Opened Feb 8, 2025
Implement negation on StructuralTangents Open

good first issue Structural Tangent

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

JuliaDiff/ChainRulesCore.jl#669 · Opened Mar 15, 2024
Factor out backing and construct into a separate lightweight package? Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

JuliaDiff/ChainRulesCore.jl#668 · 6 comments · Opened Feb 28, 2024
Removing / with tangent denominator Open

breaking

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#665 · Opened Feb 20, 2024
Errror in accumulate when I have one argument as a tuple Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#664 · 2 comments · Opened Feb 14, 2024
using ChainRulesCore changes type promotion logic Open

upsteam

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#649 · 1 comment · Opened Jan 3, 2024
ChainRulesCore.ProjectTo creates sparse matrices of the wrong element type (drops Duals) Open

bug help wanted

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#648 · 3 comments · Opened Dec 30, 2023
`tangent * tangent` and `dot(tangent, tangent)` can return tangents. Open

breaking

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#643 · 1 reaction · Opened Dec 15, 2023
typos in geometric descriptions in the docs Open

Difficulty 2/5 1-3 hours Newbie friendliness 38/100

JuliaDiff/ChainRulesCore.jl#635 · 3 comments · Opened Oct 5, 2023
tangent_type(primal_type) Open

breaking speculative Structural Tangent

Difficulty 5/5 Over a week Newbie friendliness 20/100

JuliaDiff/ChainRulesCore.jl#634 · Opened Oct 4, 2023
Get rid of `MethodError: no method matching iterate(::Nothing)` Open

breaking

Difficulty 4/5 3-5 days Newbie friendliness 30/100

JuliaDiff/ChainRulesCore.jl#632 · 1 comment · Opened Sep 29, 2023
FAQ Broken Links Open

good first issue

Difficulty 2/5 1-3 hours Newbie friendliness 48/100

JuliaDiff/ChainRulesCore.jl#625 · 3 comments · Opened Jul 27, 2023
ProjectTo causes scalar indexing when taking adjoints of complex CuArray Open

bug ProjectTo

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#624 · 1 comment · Opened Jul 21, 2023
No method matching `(::ChainRulesCore.ProjectTo)(::Tuple{Float64})` Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

JuliaDiff/ChainRulesCore.jl#623 · 9 comments · Opened Jun 16, 2023
`ProjectTo(::AbstractSparseMatrix{Bool})` should be trivial Open

bug help wanted ProjectTo

Difficulty 3/5 1-2 days Newbie friendliness 45/100

JuliaDiff/ChainRulesCore.jl#622 · 1 reaction · Opened May 29, 2023
Cannot generate `frule` seed via `one(x)` Open

design enhancement

Difficulty 5/5 Over a week Newbie friendliness 30/100

JuliaDiff/ChainRulesCore.jl#618 · 1 comment · Opened Apr 10, 2023
Make ZeroTangent() == 0 Open

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#607 · 3 comments · Opened Mar 13, 2023
Making `getproperty`, `getindex` and `iterate` more type stable for `Tangent`s Open

Structural Tangent

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#606 · 1 comment · 2 reactions · Opened Mar 1, 2023
Document how to construct Wirtinger derivative Open

Complex Differentiation documentation good first issue

Difficulty 2/5 1-3 hours Newbie friendliness 50/100

JuliaDiff/ChainRulesCore.jl#604 · 1 reaction · Opened Feb 27, 2023
Document how to define own ProjectTo's Open

documentation help wanted ProjectTo

Difficulty 2/5 1-3 hours Newbie friendliness 42/100

JuliaDiff/ChainRulesCore.jl#599 · Opened Dec 8, 2022
`Reusable` and `NonReusable` reverse mode capability Open

pending-clear-need

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#591 · 1 reaction · Opened Oct 21, 2022
ProjectTo(::Vector{Vector{Float64}}) type unstable Open

ProjectTo

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#590 · 2 comments · Opened Sep 25, 2022
writing rules for <:AbstractArray Open

documentation ProjectTo Structural Tangent

Difficulty 5/5 Over a week Newbie friendliness 18/100

JuliaDiff/ChainRulesCore.jl#582 · 1 comment · Opened Sep 2, 2022
ProjectTo access to undefined reference Open

ProjectTo

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#579 · 5 comments · Opened Aug 31, 2022
Invalidations from ChainRulesCore Tangent overload on Tail Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#576 · 14 comments · Opened Aug 21, 2022
`ProjectTo{SparseMatrixCSC}` can incorrectly assume `eltype` of projected value Open

ProjectTo

Difficulty 4/5 3-5 days Newbie friendliness 38/100

JuliaDiff/ChainRulesCore.jl#571 · 2 comments · Opened Aug 4, 2022
`rrules` do not support chunked mode Open

design documentation help wanted

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#566 · 2 comments · Opened Jul 18, 2022
Immutable setindex on Tangent Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#563 · 1 comment · Opened Jul 10, 2022
RFC: Example Rule "Gallery" to showcase CRC best practices? Open

documentation

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#549 · 4 comments · 4 reactions · Opened Mar 4, 2022
document ReverseDiff.jl integration's need to opt-in Open

documentation

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

JuliaDiff/ChainRulesCore.jl#548 · 5 comments · Opened Feb 28, 2022
Function to tell if you are being differentiated Open

enhancement

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#547 · 6 comments · Opened Feb 24, 2022
Keeping vs Disabling AutoFormatter? Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

JuliaDiff/ChainRulesCore.jl#532 · Opened Jan 12, 2022
Introduce tangent and cotangents terminology Open

documentation

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#512 · 2 comments · Opened Nov 10, 2021
How to @opt_out of rules for methods in packages that don't use CRC Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#505 · 5 comments · Opened Oct 28, 2021
Comparison tests ZeroTangent with 0-like numbers should be true Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#504 · 7 comments · Opened Oct 28, 2021
`@opt_out` scope problem Open

bug rule definition helper

Difficulty 3/5 1-2 days Newbie friendliness 48/100

JuliaDiff/ChainRulesCore.jl#499 · 1 comment · Opened Oct 23, 2021
Don't allow Tangent{T} where T is an Array or a primative type? Open

Structural Tangent

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#496 · 8 comments · Opened Oct 19, 2021
Formatter Action doesn't post comments when made from a fork Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#489 · 3 comments · Opened Oct 11, 2021
Teach Tangent{T} about NoTangent vs ZeroTangent? Open

Structural Tangent

Difficulty 4/5 3-5 days Newbie friendliness 30/100

JuliaDiff/ChainRulesCore.jl#481 · Opened Oct 6, 2021
happens-to-be-zero zero for tangent space of primal Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#476 · 7 comments · Opened Oct 2, 2021
Possible to write rules for methods not collections of methods? Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#471 · 10 comments · Opened Sep 24, 2021
Ability to specify different rules based on what combinations of inputs are actually being used Open

design

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#452 · 1 comment · 1 reaction · Opened Sep 1, 2021
Ambiguities with Base Open

good first issue

Difficulty 4/5 3-5 days Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#448 · 6 comments · Opened Aug 26, 2021
ProjectTo(Adjoint{<:SparseMatrixCSC})(::Matrix) does not preserve sparsity Open

bug ProjectTo

Difficulty 3/5 1-2 days Newbie friendliness 48/100

JuliaDiff/ChainRulesCore.jl#447 · 2 comments · 1 reaction · Opened Aug 23, 2021
Structural tangents are cool too, and SArrays can probably be primitives Open

Structural Tangent

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#441 · 30 comments · 1 reaction · Opened Aug 17, 2021
Support Functors.jl? Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#439 · 7 comments · Opened Aug 16, 2021
Projection for `x:: AbstractRange` Open

ProjectTo

Difficulty 5/5 Over a week Newbie friendliness 25/100

JuliaDiff/ChainRulesCore.jl#437 · 1 comment · 1 reaction · Opened Aug 16, 2021
Projections do not play well with GPUCompiler Open

ProjectTo

Difficulty 4/5 3-5 days Newbie friendliness 30/100

JuliaDiff/ChainRulesCore.jl#429 · 2 comments · 1 reaction · Opened Aug 9, 2021
add Zygote to Integration tests Open

infrastructure

Difficulty 2/5 1-3 hours Newbie friendliness 35/100

JuliaDiff/ChainRulesCore.jl#415 · 1 comment · Opened Jul 27, 2021
InplacableThunk and subspace types Open

inplace accumulation

Difficulty 5/5 Over a week Newbie friendliness 20/100

JuliaDiff/ChainRulesCore.jl#411 · Opened Jul 26, 2021

JuliaDiff/ChainRulesCore.jl

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