From fbc7d72c9e5caafc14bd8dada4a291b4e2fa5121 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Mon, 20 May 2024 15:25:44 +0100
Subject: [PATCH] muladd! with adjoints/transposes (#233)

---
 Project.toml        | 2 +-
 src/ArrayLayouts.jl | 4 ++++
 src/muladd.jl       | 2 +-
 test/test_muladd.jl | 8 ++++++++
 4 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Project.toml b/Project.toml
index 46e8881..6b8be30 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ArrayLayouts"
 uuid = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 authors = ["Sheehan Olver <solver@mac.com>"]
-version = "1.9.2"
+version = "1.9.3"
 
 [deps]
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
diff --git a/src/ArrayLayouts.jl b/src/ArrayLayouts.jl
index e22ccba..d0d323d 100644
--- a/src/ArrayLayouts.jl
+++ b/src/ArrayLayouts.jl
@@ -285,6 +285,10 @@ Base.permutedims(D::Diagonal{<:Any,<:LayoutVector}) = D
 
 zero!(A) = zero!(MemoryLayout(A), A)
 zero!(_, A) = fill!(A,zero(eltype(A)))
+function zero!(::DualLayout, A)
+    zero!(parent(A))
+    A
+end
 function zero!(_, A::AbstractArray{<:AbstractArray})
     for a in A
         zero!(a)
diff --git a/src/muladd.jl b/src/muladd.jl
index bcb4ee4..5f36c78 100644
--- a/src/muladd.jl
+++ b/src/muladd.jl
@@ -77,7 +77,7 @@ materialize(M::MulAdd) = copy(instantiate(M))
 copy(M::MulAdd) = copyto!(similar(M), M)
 
 _fill_copyto!(dest, C) = copyto!(dest, C)
-_fill_copyto!(dest, C::Zeros) = zero!(dest) # exploit special fill! overload
+_fill_copyto!(dest, C::Union{Zeros,AdjOrTrans{<:Any,<:Zeros}}) = zero!(dest) # exploit special fill! overload
 
 @inline copyto!(dest::AbstractArray{T}, M::MulAdd) where T =
     muladd!(M.α, unalias(dest,M.A), unalias(dest,M.B), M.β, _fill_copyto!(dest, M.C); Czero = M.Czero)
diff --git a/test/test_muladd.jl b/test/test_muladd.jl
index 49ce7eb..24a6eaa 100644
--- a/test/test_muladd.jl
+++ b/test/test_muladd.jl
@@ -844,6 +844,14 @@ Random.seed!(0)
             @test copy(M) ≈ b * D * α + c * β
         end
     end
+
+    @testset "dual" begin
+        a = randn(5)
+        X = randn(5,6)
+        @test copyto!(similar(a,6)', MulAdd(2.0, a', X, 3.0, Zeros(6)')) ≈ 2a'*X
+        @test copyto!(transpose(similar(a,6)), MulAdd(2.0, a', X, 3.0, Zeros(6)')) ≈ 2a'*X
+        @test copyto!(transpose(similar(a,6)), MulAdd(2.0, transpose(a), X, 3.0, transpose(Zeros(6)))) ≈ 2a'*X
+    end
 end
 
 end