From f3f43b46d1c1d184dce65905d48b9a11f2dd1fb7 Mon Sep 17 00:00:00 2001
From: Michael Abbott <me@escbook>
Date: Sat, 26 Dec 2020 16:29:25 +0100
Subject: [PATCH 1/5] tweaks to sum rules

---
 src/rulesets/Base/mapreduce.jl | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/src/rulesets/Base/mapreduce.jl b/src/rulesets/Base/mapreduce.jl
index 33eae96d1..0885a4fa5 100644
--- a/src/rulesets/Base/mapreduce.jl
+++ b/src/rulesets/Base/mapreduce.jl
@@ -10,9 +10,10 @@ function rrule(::typeof(sum), x::AbstractArray{T}; dims=:) where {T<:Number}
     y = sum(x; dims=dims)
     function sum_pullback(ȳ)
         # broadcasting the two works out the size no-matter `dims`
-        x̄ = broadcast(x, ȳ) do xi, ȳi
-            ȳi
-        end
+        x̄ = InplaceableThunk(
+            @thunk(broadcast((_,y1)->y1, x, ȳ)), # last∘tuple
+            x -> x .+= x̄
+        )
         return (NO_FIELDS, x̄)
     end
     return y, sum_pullback
@@ -29,7 +30,9 @@ function frule(
     ∂y = if dims isa Colon
         2 * real(dot(x, ẋ))
     elseif VERSION ≥ v"1.2" # multi-iterator mapreduce introduced in v1.2
-        2 * mapreduce(_realconjtimes, +, x, ẋ; dims=dims)
+        mapreduce(+, x, ẋ; dims=dims) do xi, dxi
+            2 * _realconjtimes(xi, dxi)
+        end
     else
         2 * sum(_realconjtimes.(x, ẋ); dims=dims)
     end
@@ -44,7 +47,11 @@ function rrule(
 ) where {T<:Union{Real,Complex}}
     y = sum(abs2, x; dims=dims)
     function sum_abs2_pullback(ȳ)
-        return (NO_FIELDS, DoesNotExist(), 2 .* real.(ȳ) .* x)
+        x_thunk = InplaceableThunk(
+            @thunk(2 .* real.(ȳ) .* x),
+            dx -> dx .+= 2 .* real.(ȳ) .* x
+        )
+        return (NO_FIELDS, DoesNotExist(), x_thunk)
     end
     return y, sum_abs2_pullback
 end

From 7d2050c84fe34d958ef3347f280c171e890c1f31 Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Thu, 6 May 2021 19:11:54 -0400
Subject: [PATCH 2/5] Apply suggestions from code review

Co-authored-by: Lyndon White <oxinabox@ucc.asn.au>
---
 src/rulesets/Base/mapreduce.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/rulesets/Base/mapreduce.jl b/src/rulesets/Base/mapreduce.jl
index 0885a4fa5..bf8b57d35 100644
--- a/src/rulesets/Base/mapreduce.jl
+++ b/src/rulesets/Base/mapreduce.jl
@@ -11,8 +11,8 @@ function rrule(::typeof(sum), x::AbstractArray{T}; dims=:) where {T<:Number}
     function sum_pullback(ȳ)
         # broadcasting the two works out the size no-matter `dims`
         x̄ = InplaceableThunk(
-            @thunk(broadcast((_,y1)->y1, x, ȳ)), # last∘tuple
-            x -> x .+= x̄
+            @thunk(broadcast(last∘tuple, x, ȳ))
+            x -> x .+= ȳ
         )
         return (NO_FIELDS, x̄)
     end

From 8b9584887ad10779cac2d8923898d4775d79b0a5 Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Thu, 6 May 2021 19:30:29 -0400
Subject: [PATCH 3/5] comma

---
 src/rulesets/Base/mapreduce.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/rulesets/Base/mapreduce.jl b/src/rulesets/Base/mapreduce.jl
index bf8b57d35..2f5b5003a 100644
--- a/src/rulesets/Base/mapreduce.jl
+++ b/src/rulesets/Base/mapreduce.jl
@@ -11,7 +11,7 @@ function rrule(::typeof(sum), x::AbstractArray{T}; dims=:) where {T<:Number}
     function sum_pullback(ȳ)
         # broadcasting the two works out the size no-matter `dims`
         x̄ = InplaceableThunk(
-            @thunk(broadcast(last∘tuple, x, ȳ))
+            @thunk(broadcast(last∘tuple, x, ȳ)),
             x -> x .+= ȳ
         )
         return (NO_FIELDS, x̄)

From 2b882c1f155f2ad54291f80281d55127b3edce8a Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Thu, 6 May 2021 20:27:54 -0400
Subject: [PATCH 4/5] v0.7.62

---
 Project.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 091b85f08..2c4004059 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "ChainRules"
 uuid = "082447d4-558c-5d27-93f4-14fc19e9eca2"
-version = "0.7.41"
+version = "0.7.62"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"

From 082c73ccc19f633f140a99de968b09c51e2afa62 Mon Sep 17 00:00:00 2001
From: Michael Abbott <32575566+mcabbott@users.noreply.github.com>
Date: Fri, 7 May 2021 13:02:09 -0400
Subject: [PATCH 5/5] gone cold one more time...

Co-authored-by: David Widmann <devmotion@users.noreply.github.com>
---
 Project.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 9a732804b..0a7537005 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,6 +1,6 @@
 name = "ChainRules"
 uuid = "082447d4-558c-5d27-93f4-14fc19e9eca2"
-version = "0.7.62"
+version = "0.7.63"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"