Removes rules depending on casted (#120)

* Remove used of Casted

* bump version

* Update Project.toml

Project.toml

@@ -1,6 +1,6 @@
 name = "ChainRules"
 uuid = "082447d4-558c-5d27-93f4-14fc19e9eca2"
-version = "0.2.1"
+version = "0.2.2-DEV"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
@@ -10,7 +10,7 @@ Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 
 [compat]
-ChainRulesCore = "^0.3"
+ChainRulesCore = "0.3, 0.4"
 FiniteDifferences = "^0.7"
 julia = "^1.0"
 

src/rulesets/Base/broadcast.jl

@@ -16,15 +16,15 @@ end
 function frule(::typeof(broadcast), f, x)
     Ω, ∂x = _cast_diff(f, x)
     function broadcast_pushforward(_, Δf, Δx)
-        return Δx * cast(∂x)
+        return Δx .* ∂x
     end
     return Ω, broadcast_pushforward
 end
 
 function rrule(::typeof(broadcast), f, x)
     values, derivs = _cast_diff(f, x)
     function broadcast_pullback(ΔΩ)
-        return (NO_FIELDS, DNE(), @thunk(ΔΩ * cast(derivs)))
+        return (NO_FIELDS, DNE(), @thunk(ΔΩ .* derivs))
     end
     return values, broadcast_pullback
 end

src/rulesets/Base/mapreduce.jl

@@ -59,7 +59,7 @@ end
 
 function rrule(::typeof(sum), x)
     function sum_pullback(ȳ)
-        return (NO_FIELDS, cast(ȳ))
+        return (NO_FIELDS, @thunk(fill(ȳ, size(x))))
     end
     return sum(x), sum_pullback
 end

src/rulesets/LinearAlgebra/dense.jl

@@ -10,14 +10,14 @@ const SquareMatrix{T} = Union{Diagonal{T},AbstractTriangular{T}}
 
 function frule(::typeof(dot), x, y)
     function dot_pushforward(Δself, Δx, Δy)
-        return sum(Δx * cast(y)) + sum(cast(x) * Δy)
+        return sum(Δx .* y) + sum(x .* Δy)
     end
     return dot(x, y), dot_pushforward
 end
 
 function rrule(::typeof(dot), x, y)
     function dot_pullback(ΔΩ)
-        return (NO_FIELDS, ΔΩ * cast(y), cast(x) * ΔΩ,)
+        return (NO_FIELDS, @thunk(ΔΩ .* y), @thunk(x .* ΔΩ))
     end
     return dot(x, y), dot_pullback
 end

test/rulesets/Base/base.jl

@@ -136,7 +136,7 @@
 
         z̄ = rand(3, 5)
         (ds, dx, dy) = pullback(z̄)
-        
+
         @test ds === NO_FIELDS
 
         @test extern(dx) == extern(accumulate(zeros(3, 2), dx))
@@ -147,22 +147,13 @@
     end
 
     @testset "hypot(x, y)" begin
-        x, y = rand(2)
-        h, pushforward = frule(hypot, x, y)
-        dxy(x, y) = pushforward(NamedTuple(), x, y)
-
-        @test extern(dxy(One(), Zero())) === x / h
-        @test extern(dxy(Zero(), One())) === y / h
-
-        cx, cy = cast((One(), Zero())), cast((Zero(), One()))
-        dx, dy = extern(dxy(cx, cy))
-        @test dx === x / h
-        @test dy === y / h
-
-        cx, cy = cast((rand(), Zero())), cast((Zero(), rand()))
-        dx, dy = extern(dxy(cx, cy))
-        @test dx === x / h * cx.value[1]
-        @test dy === y / h * cy.value[2]
+        rng = MersenneTwister(123456)
+        x, Δx, x̄ = randn(rng, 3)
+        y, Δy, ȳ = randn(rng, 3)
+        Δz = randn(rng)
+
+        frule_test(hypot, (x, Δx), (y, Δy))
+        rrule_test(hypot, Δz, (x, x̄), (y, ȳ))
     end
 
     @testset "identity" begin

test/runtests.jl

@@ -10,9 +10,9 @@ using Statistics
 using Test
 
 # For testing purposes we use a lot of
-using ChainRulesCore: cast, extern, accumulate, accumulate!, store!, @scalar_rule,
+using ChainRulesCore: extern, accumulate, accumulate!, store!, @scalar_rule,
     Wirtinger, wirtinger_primal, wirtinger_conjugate,
-    Zero, One, Casted, DNE, Thunk, AbstractDifferential
+    Zero, One, DNE, Thunk, AbstractDifferential
 
 include("test_util.jl")
 

test/test_util.jl

@@ -193,12 +193,11 @@ end
 function Base.isapprox(ad::Wirtinger, fd; kwargs...)
     error("Finite differencing with Wirtinger rules not implemented")
 end
-function Base.isapprox(d_ad::Casted, d_fd; kwargs...)
-    return all(isapprox.(extern(d_ad), d_fd; kwargs...))
-end
+
 function Base.isapprox(d_ad::DNE, d_fd; kwargs...)
     error("Tried to differentiate w.r.t. a DNE")
 end
+
 function Base.isapprox(d_ad::AbstractDifferential, d_fd; kwargs...)
     return isapprox(extern(d_ad), d_fd; kwargs...)
 end