Replace NO_FIELDS by NoTangent()

Project.toml

@@ -1,6 +1,6 @@
 name = "ChainRules"
 uuid = "082447d4-558c-5d27-93f4-14fc19e9eca2"
-version = "0.7.70"
+version = "0.8.0"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
@@ -12,8 +12,8 @@ Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]
-ChainRulesCore = "0.9.44"
-ChainRulesTestUtils = "0.6.8"
+ChainRulesCore = "0.10"
+ChainRulesTestUtils = "0.7"
 Compat = "3.30"
 FiniteDifferences = "0.12.8"
 Reexport = "0.2, 1"

src/ChainRules.jl

@@ -2,7 +2,6 @@ module ChainRules
 
 using Reexport
 @reexport using ChainRulesCore
-export Zero, DoesNotExist, Composite, AbstractDifferential
 
 using Base.Broadcast: materialize, materialize!, broadcasted, Broadcasted, broadcastable
 using Compat

src/rulesets/Base/array.jl

@@ -5,7 +5,7 @@
 function rrule(::typeof(reshape), A::AbstractArray, dims::Tuple{Vararg{Int}})
     A_dims = size(A)
     function reshape_pullback(Ȳ)
-        return (NO_FIELDS, reshape(Ȳ, A_dims), NoTangent())
+        return (NoTangent(), reshape(Ȳ, A_dims), NoTangent())
     end
     return reshape(A, dims), reshape_pullback
 end
@@ -15,7 +15,7 @@ function rrule(::typeof(reshape), A::AbstractArray, dims::Int...)
     function reshape_pullback(Ȳ)
         ∂A = reshape(Ȳ, A_dims)
         ∂dims = broadcast(_ -> NoTangent(), dims)
-        return (NO_FIELDS, ∂A, ∂dims...)
+        return (NoTangent(), ∂A, ∂dims...)
     end
     return reshape(A, dims...), reshape_pullback
 end
@@ -28,7 +28,7 @@ function rrule(::typeof(hcat), A::AbstractArray, Bs::AbstractArray...)
     function hcat_pullback(Ȳ)
         Xs = (A, Bs...)
         ntuple(length(Bs) + 2) do full_i
-            full_i == 1 && return NO_FIELDS
+            full_i == 1 && return NoTangent()
 
             i = full_i - 1
             l = mapreduce(j->size(Xs[j], 2), Base.add_sum, 1:i-1; init=0)
@@ -50,7 +50,7 @@ function rrule(::typeof(reduce), ::typeof(hcat), As::AbstractVector{<:AbstractVe
             pre = post - diff + 1
             return ΔY[:, pre:post]
         end
-        return (NO_FIELDS, NoTangent(), ∂As)
+        return (NoTangent(), NoTangent(), ∂As)
     end
     return reduce(hcat, As), reduce_hcat_pullback
 end
@@ -68,7 +68,7 @@ function rrule(::typeof(vcat), A::AbstractArray, Bs::AbstractArray...)
             u = l + size(Bs[i], 1)
             copy(selectdim(Ȳ, 1, l+1:u))
         end
-        return (NO_FIELDS, ∂A, ∂Bs...)
+        return (NoTangent(), ∂A, ∂Bs...)
     end
     return vcat(A, Bs...), vcat_pullback
 end
@@ -81,7 +81,7 @@ function rrule(::typeof(reduce), ::typeof(vcat), As::AbstractVector{<:AbstractVe
             pre = post - diff + 1
             return ΔY[pre:post, :]
         end
-        return (NO_FIELDS, NoTangent(), ∂As)
+        return (NoTangent(), NoTangent(), ∂As)
     end
     return reduce(vcat, As), reduce_vcat_pullback
 end
@@ -92,14 +92,14 @@ end
 
 function rrule(::typeof(fill), value::Any, dims::Tuple{Vararg{Int}})
     function fill_pullback(Ȳ)
-        return (NO_FIELDS, sum(Ȳ), NoTangent())
+        return (NoTangent(), sum(Ȳ), NoTangent())
     end
     return fill(value, dims), fill_pullback
 end
 
 function rrule(::typeof(fill), value::Any, dims::Int...)
     function fill_pullback(Ȳ)
-        return (NO_FIELDS, sum(Ȳ), ntuple(_->NoTangent(), length(dims))...)
+        return (NoTangent(), sum(Ȳ), ntuple(_->NoTangent(), length(dims))...)
     end
     return fill(value, dims), fill_pullback
 end

src/rulesets/Base/arraymath.jl

@@ -10,7 +10,7 @@ end
 function rrule(::typeof(inv), x::AbstractArray)
     Ω = inv(x)
     function inv_pullback(ΔΩ)
-        return NO_FIELDS, -Ω' * ΔΩ * Ω'
+        return NoTangent(), -Ω' * ΔΩ * Ω'
     end
     return Ω, inv_pullback
 end
@@ -26,7 +26,7 @@ function rrule(
 )
     function times_pullback(Ȳ)
         return (
-            NO_FIELDS,
+            NoTangent(),
             InplaceableThunk(
                 @thunk(Ȳ * B'),
                 X̄ -> mul!(X̄, Ȳ, B', true, true)
@@ -48,7 +48,7 @@ function rrule(
     function times_pullback(Ȳ)
         @assert size(B, 1) === 1   # otherwise primal would have failed.
         return (
-            NO_FIELDS,
+            NoTangent(),
             InplaceableThunk(
                 @thunk(Ȳ * vec(B')),
                 X̄ -> mul!(X̄, Ȳ, vec(B'), true, true)
@@ -67,7 +67,7 @@ function rrule(
 )
     function times_pullback(Ȳ)
         return (
-            NO_FIELDS,
+            NoTangent(),
             @thunk(dot(Ȳ, B)'),
             InplaceableThunk(
                 @thunk(A' * Ȳ),
@@ -83,7 +83,7 @@ function rrule(
 )
     function times_pullback(Ȳ)
         return (
-            NO_FIELDS,
+            NoTangent(),
             InplaceableThunk(
                 @thunk(A' * Ȳ),
                 X̄ -> mul!(X̄, conj(A), Ȳ, true, true)
@@ -118,7 +118,7 @@ function rrule(
             )
         )
         addon = if z isa Bool
-            DoesNotExist()
+            NoTangent()
         elseif z isa Number
             @thunk(sum(Ȳ))
         else
@@ -127,7 +127,7 @@ function rrule(
                 dz -> sum!(dz, Ȳ; init=false)
             )
         end
-        (NO_FIELDS, matmul..., addon)
+        (NoTangent(), matmul..., addon)
     end
     return muladd(A, B, z), muladd_pullback_1
 end
@@ -148,7 +148,7 @@ function rrule(
             @thunk(ut' .* dy),
             dv -> dv .+= ut' .* dy
         )
-        (NO_FIELDS, ut_thunk, v_thunk, z isa Bool ? DoesNotExist() : dy)
+        (NoTangent(), ut_thunk, v_thunk, z isa Bool ? NoTangent() : dy)
     end
     return muladd(ut, v, z), muladd_pullback_2
 end
@@ -166,7 +166,7 @@ function rrule(
             @thunk(vec(sum(u .* conj.(Ȳ), dims=1))'),
         )
         addon = if z isa Bool
-            DoesNotExist()
+            NoTangent()
         elseif z isa Number
             @thunk(sum(Ȳ))
         else
@@ -175,7 +175,7 @@ function rrule(
                 dz -> sum!(dz, Ȳ; init=false)
             )
         end
-        (NO_FIELDS, proj..., addon)
+        (NoTangent(), proj..., addon)
     end
     return muladd(u, vt, z), muladd_pullback_3
 end
@@ -197,7 +197,7 @@ function rrule(::typeof(/), A::AbstractVecOrMat{<:Real}, B::AbstractVecOrMat{<:R
         ∂A = last(dA_pb(unthunk(dAᵀ)))
         ∂B = last(dA_pb(unthunk(dBᵀ)))
 
-        (NO_FIELDS, ∂A, ∂B)
+        (NoTangent(), ∂A, ∂B)
     end
     return C, slash_pullback
 end
@@ -217,7 +217,7 @@ function rrule(::typeof(\), A::AbstractVecOrMat{<:Real}, B::AbstractVecOrMat{<:R
             Ā
         end
         ∂B = @thunk A' \ Ȳ
-        return NO_FIELDS, ∂A, ∂B
+        return NoTangent(), ∂A, ∂B
     end
     return Y, backslash_pullback
 
@@ -230,15 +230,15 @@ end
 function rrule(::typeof(/), A::AbstractArray{<:Real}, b::Real)
     Y = A/b
     function slash_pullback(Ȳ)
-        return (NO_FIELDS, @thunk(Ȳ/b), @thunk(-dot(Ȳ, Y)/b))
+        return (NoTangent(), @thunk(Ȳ/b), @thunk(-dot(Ȳ, Y)/b))
     end
     return Y, slash_pullback
 end
 
 function rrule(::typeof(\), b::Real, A::AbstractArray{<:Real})
     Y = b\A
     function backslash_pullback(Ȳ)
-        return (NO_FIELDS, @thunk(-dot(Ȳ, Y)/b), @thunk(Ȳ/b))
+        return (NoTangent(), @thunk(-dot(Ȳ, Y)/b), @thunk(Ȳ/b))
     end
     return Y, backslash_pullback
 end
@@ -249,7 +249,7 @@ end
 
 function rrule(::typeof(-), x::AbstractArray)
     function negation_pullback(ȳ)
-        return NO_FIELDS, InplaceableThunk(@thunk(-ȳ), ā -> ā .-= ȳ)
+        return NoTangent(), InplaceableThunk(@thunk(-ȳ), ā -> ā .-= ȳ)
     end
     return -x, negation_pullback
 end

src/rulesets/Base/base.jl

@@ -10,7 +10,7 @@
 frule((_, Δz), ::typeof(adjoint), z::Number) = (z', Δz')
 
 function rrule(::typeof(adjoint), z::Number)
-    adjoint_pullback(ΔΩ) = (NO_FIELDS, ΔΩ')
+    adjoint_pullback(ΔΩ) = (NoTangent(), ΔΩ')
     return (z', adjoint_pullback)
 end
 
@@ -22,7 +22,7 @@ frule((_, Δz), ::typeof(real), z::Number) = (real(z), real(Δz))
 
 function rrule(::typeof(real), z::Number)
     # add zero(z) to embed the real number in the same number type as z
-    real_pullback(ΔΩ) = (NO_FIELDS, real(ΔΩ) + zero(z))
+    real_pullback(ΔΩ) = (NoTangent(), real(ΔΩ) + zero(z))
     return (real(z), real_pullback)
 end
 
@@ -33,7 +33,7 @@ end
 frule((_, Δz), ::typeof(imag), z::Complex) = (imag(z), imag(Δz))
 
 function rrule(::typeof(imag), z::Complex)
-    imag_pullback(ΔΩ) = (NO_FIELDS, real(ΔΩ) * im)
+    imag_pullback(ΔΩ) = (NoTangent(), real(ΔΩ) * im)
     return (imag(z), imag_pullback)
 end
 
@@ -45,15 +45,15 @@ function frule((_, Δx, Δy), ::Type{T}, x::Number, y::Number) where {T<:Complex
 end
 
 function rrule(::Type{T}, z::Complex) where {T<:Complex}
-    Complex_pullback(ΔΩ) = (NO_FIELDS, Complex(ΔΩ))
+    Complex_pullback(ΔΩ) = (NoTangent(), Complex(ΔΩ))
     return (T(z), Complex_pullback)
 end
 function rrule(::Type{T}, x::Real) where {T<:Complex}
-    Complex_pullback(ΔΩ) = (NO_FIELDS, real(ΔΩ))
+    Complex_pullback(ΔΩ) = (NoTangent(), real(ΔΩ))
     return (T(x), Complex_pullback)
 end
 function rrule(::Type{T}, x::Number, y::Number) where {T<:Complex}
-    Complex_pullback(ΔΩ) = (NO_FIELDS, real(ΔΩ), imag(ΔΩ))
+    Complex_pullback(ΔΩ) = (NoTangent(), real(ΔΩ), imag(ΔΩ))
     return (T(x, y), Complex_pullback)
 end
 
@@ -70,7 +70,7 @@ end
 function rrule(::typeof(hypot), z::Complex)
     Ω = hypot(z)
     function hypot_pullback(ΔΩ)
-        return (NO_FIELDS, (real(ΔΩ) / ifelse(iszero(Ω), one(Ω), Ω)) * z)
+        return (NoTangent(), (real(ΔΩ) / ifelse(iszero(Ω), one(Ω), Ω)) * z)
     end
     return (Ω, hypot_pullback)
 end
@@ -148,7 +148,7 @@ end
 
 function rrule(::typeof(identity), x)
     function identity_pullback(ȳ)
-        return (NO_FIELDS, ȳ)
+        return (NoTangent(), ȳ)
     end
     return (x, identity_pullback)
 end

src/rulesets/Base/evalpoly.jl

@@ -15,7 +15,7 @@ if VERSION ≥ v"1.4"
         y, ys = _evalpoly_intermediates(x, p)
         function evalpoly_pullback(Δy)
             ∂x, ∂p = _evalpoly_back(x, p, ys, Δy)
-            return NO_FIELDS, ∂x, ∂p
+            return NoTangent(), ∂x, ∂p
         end
         return y, evalpoly_pullback
     end