Add dot overloads for Zero and One (#201)

* Add LinearAlgebra as dependancy

* Add overrides for dot

* Test dot rules

* Increment version number

* Increment version number

* Add dot overloads for DoesNotExist

* Add missing overload

* Add comment

Co-authored-by: Lyndon White <oxinabox@ucc.asn.au>

* Don't use 1

Co-authored-by: Lyndon White <oxinabox@ucc.asn.au>

Co-authored-by: Lyndon White <oxinabox@ucc.asn.au>

Author: sethaxen

Project.toml

@@ -1,8 +1,9 @@
 name = "ChainRulesCore"
 uuid = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
-version = "0.9.9"
+version = "0.9.10"
 
 [deps]
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MuladdMacro = "46d2c3a1-f734-5fdb-9937-b9b9aeba4221"
 
 [compat]
@@ -15,9 +16,8 @@ julia = "^1.0"
 [extras]
 BenchmarkTools = "6e4b80f9-dd63-53aa-95a3-0cdb28fa8baf"
 FiniteDifferences = "26cc04aa-876d-5657-8c51-4c34ba976000"
-LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test", "BenchmarkTools", "FiniteDifferences", "LinearAlgebra", "StaticArrays"]
+test = ["Test", "BenchmarkTools", "FiniteDifferences", "StaticArrays"]

src/ChainRulesCore.jl

@@ -1,5 +1,6 @@
 module ChainRulesCore
 using Base.Broadcast: broadcasted, Broadcasted, broadcastable, materialize, materialize!
+using LinearAlgebra: LinearAlgebra
 using MuladdMacro: @muladd
 
 export on_new_rule, refresh_rules  # generation tools

src/differential_arithmetic.jl

@@ -18,6 +18,7 @@ Base.:+(::DoesNotExist, ::DoesNotExist) = DoesNotExist()
 Base.:-(::DoesNotExist, ::DoesNotExist) = DoesNotExist()
 Base.:-(::DoesNotExist) = DoesNotExist()
 Base.:*(::DoesNotExist, ::DoesNotExist) = DoesNotExist()
+LinearAlgebra.dot(::DoesNotExist, ::DoesNotExist) = DoesNotExist()
 for T in (:One, :AbstractThunk, :Composite, :Any)
     @eval Base.:+(::DoesNotExist, b::$T) = b
     @eval Base.:+(a::$T, ::DoesNotExist) = a
@@ -26,6 +27,9 @@ for T in (:One, :AbstractThunk, :Composite, :Any)
 
     @eval Base.:*(::DoesNotExist, ::$T) = DoesNotExist()
     @eval Base.:*(::$T, ::DoesNotExist) = DoesNotExist()
+
+    @eval LinearAlgebra.dot(::DoesNotExist, ::$T) = DoesNotExist()
+    @eval LinearAlgebra.dot(::$T, ::DoesNotExist) = DoesNotExist()
 end
 # `DoesNotExist` and `Zero` have special relationship,
 # DoesNotExist wins add, Zero wins *. This is (in theory) to allow `*` to be used for
@@ -37,6 +41,9 @@ Base.:-(::Zero, ::DoesNotExist) = DoesNotExist()
 Base.:*(::DoesNotExist, ::Zero) = Zero()
 Base.:*(::Zero, ::DoesNotExist) = Zero()
 
+LinearAlgebra.dot(::DoesNotExist, ::Zero) = Zero()
+LinearAlgebra.dot(::Zero, ::DoesNotExist) = Zero()
+
 Base.muladd(::Zero, x, y) = y
 Base.muladd(x, ::Zero, y) = y
 Base.muladd(x, y, ::Zero) = x*y
@@ -51,6 +58,7 @@ Base.:+(::Zero, ::Zero) = Zero()
 Base.:-(::Zero, ::Zero) = Zero()
 Base.:-(::Zero) = Zero()
 Base.:*(::Zero, ::Zero) = Zero()
+LinearAlgebra.dot(::Zero, ::Zero) = Zero()
 for T in (:One, :AbstractThunk, :Composite, :Any)
     @eval Base.:+(::Zero, b::$T) = b
     @eval Base.:+(a::$T, ::Zero) = a
@@ -59,6 +67,9 @@ for T in (:One, :AbstractThunk, :Composite, :Any)
 
     @eval Base.:*(::Zero, ::$T) = Zero()
     @eval Base.:*(::$T, ::Zero) = Zero()
+
+    @eval LinearAlgebra.dot(::Zero, ::$T) = Zero()
+    @eval LinearAlgebra.dot(::$T, ::Zero) = Zero()
 end
 
 Base.real(::Zero) = Zero()
@@ -88,6 +99,8 @@ for T in (:AbstractThunk, :Composite, :Any)
     @eval Base.:*(a::$T, ::One) = a
 end
 
+LinearAlgebra.dot(::One, x::Number) = x
+LinearAlgebra.dot(x::Number, ::One) = conj(x)  # see definition of Frobenius inner product
 
 Base.:+(a::AbstractThunk, b::AbstractThunk) = unthunk(a) + unthunk(b)
 Base.:*(a::AbstractThunk, b::AbstractThunk) = unthunk(a) * unthunk(b)

test/differentials/abstract_zero.jl

@@ -15,8 +15,13 @@
         @test 1 - z === 1
         @test -z === z
         @test z * z === z
-        @test z * 1 === Zero()
-        @test 1 * z === Zero()
+        @test z * 11.1 === Zero()
+        @test 12.3 * z === Zero()
+        @test dot(z, z) === z
+        @test dot(z, 1.8) === z
+        @test dot(2.1, z) === z
+        @test dot([1, 2], z) === z
+        @test dot(z, [1, 2]) === z
         for x in z
             @test x === z
         end
@@ -67,8 +72,11 @@
         @test 1 - dne == 1
         @test -dne == dne
         @test dne * dne == dne
-        @test dne * 1 == dne
-        @test 1 * dne == dne
+        @test dne * 11.1 == dne
+        @test 12.1 * dne == dne
+        @test dot(dne, dne) == dne
+        @test dot(dne, 17.2) == dne
+        @test dot(11.9, dne) == dne
 
         @test Zero() + dne == dne
         @test dne + Zero() == dne
@@ -77,6 +85,8 @@
 
         @test Zero() * dne == Zero()
         @test dne * Zero() == Zero()
+        @test dot(Zero(), dne) == Zero()
+        @test dot(dne, Zero()) == Zero()
 
         for x in dne
             @test x === dne

test/differentials/composite.jl

@@ -185,9 +185,13 @@ end
 
         @test DoesNotExist() * c == DoesNotExist()
         @test c * DoesNotExist() == DoesNotExist()
+        @test dot(DoesNotExist(), c) == DoesNotExist()
+        @test dot(c, DoesNotExist()) == DoesNotExist()
 
         @test Zero() * c == Zero()
         @test c * Zero() == Zero()
+        @test dot(Zero(), c) == Zero()
+        @test dot(c, Zero()) == Zero()
 
         @test One() * c === c
         @test c * One() === c

test/differentials/one.jl

@@ -5,8 +5,10 @@
     @test o + 1 == 2
     @test 1 + o == 2
     @test o * o == o
-    @test o * 1 == 1
-    @test 1 * o == 1
+    @test o * 17 == 17
+    @test 6 * o == 6
+    @test dot(2 + im, o) == 2 - im
+    @test dot(o, 2 + im) == 2 + im
     for x in o
         @test x === o
     end

test/runtests.jl

@@ -1,7 +1,7 @@
 using Base.Broadcast: broadcastable
 using BenchmarkTools
 using ChainRulesCore
-using LinearAlgebra: Diagonal
+using LinearAlgebra: Diagonal, dot
 using FiniteDifferences
 using Test