From dbefc57abc8f21e025e05909216d81cc87792f5f Mon Sep 17 00:00:00 2001
From: Jishnu Bhattacharya <jishnub.github@gmail.com>
Date: Wed, 26 Feb 2025 12:52:24 +0530
Subject: [PATCH 1/3] Forward `Diagonal` `rmul!`/`lmul!` for adj/trans to
 parent

---
 src/diagonal.jl  | 14 ++++++++++++++
 test/diagonal.jl | 14 ++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/diagonal.jl b/src/diagonal.jl
index 90572d7b..b5642800 100644
--- a/src/diagonal.jl
+++ b/src/diagonal.jl
@@ -360,6 +360,13 @@ function rmul!(A::AbstractMatrix, D::Diagonal)
     end
     return A
 end
+# A' = A' * D => A = D' * A
+# This uses the fact that D' is a Diagonal
+function rmul!(A::AdjOrTransAbsMat, D::Diagonal)
+    f = wrapperop(A)
+    lmul!(f(D), f(A))
+    A
+end
 # T .= T * D
 function rmul!(T::Tridiagonal, D::Diagonal)
     matmul_size_check(size(T), size(D))
@@ -395,6 +402,13 @@ function lmul!(D::Diagonal, T::Tridiagonal)
     end
     return T
 end
+# A' = D * A' => A = A * D'
+# This uses the fact that D' is a Diagonal
+function lmul!(D::Diagonal, A::AdjOrTransAbsMat)
+    f = wrapperop(A)
+    rmul!(f(A), f(D))
+    A
+end
 
 @inline function __muldiag_nonzeroalpha!(out, D::Diagonal, B, alpha::Number, beta::Number)
     @inbounds for j in axes(B, 2)
diff --git a/test/diagonal.jl b/test/diagonal.jl
index 3dd334aa..bceb2c4b 100644
--- a/test/diagonal.jl
+++ b/test/diagonal.jl
@@ -1257,6 +1257,20 @@ end
     end
 end
 
+@testset "rmul!/lmul! for adj/trans" begin
+    A = rand(5,4); B = similar(A)
+    for f in (adjoint, transpose)
+        D = Diagonal(rand(size(A,1)))
+        B .= A
+        rmul!(f(B), D)
+        @test f(B) == f(A) * D
+        D = Diagonal(rand(size(A,2)))
+        B .= A
+        lmul!(D, f(B))
+        @test f(B) == D * f(A)
+    end
+end
+
 struct SMatrix1{T} <: AbstractArray{T,2}
     elt::T
 end

From fda040168e47737b106e25034b7810d754d2fe08 Mon Sep 17 00:00:00 2001
From: Jishnu Bhattacharya <jishnub.github@gmail.com>
Date: Wed, 26 Feb 2025 12:59:45 +0530
Subject: [PATCH 2/3] Add tests for complex arrays

---
 test/diagonal.jl | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/test/diagonal.jl b/test/diagonal.jl
index bceb2c4b..6f6bbabb 100644
--- a/test/diagonal.jl
+++ b/test/diagonal.jl
@@ -1258,16 +1258,18 @@ end
 end
 
 @testset "rmul!/lmul! for adj/trans" begin
-    A = rand(5,4); B = similar(A)
-    for f in (adjoint, transpose)
-        D = Diagonal(rand(size(A,1)))
-        B .= A
-        rmul!(f(B), D)
-        @test f(B) == f(A) * D
-        D = Diagonal(rand(size(A,2)))
-        B .= A
-        lmul!(D, f(B))
-        @test f(B) == D * f(A)
+    for T in (Float64, ComplexF64)
+        A = rand(T,5,4); B = similar(A)
+        for f in (adjoint, transpose)
+            D = Diagonal(rand(size(A,1)))
+            B .= A
+            rmul!(f(B), D)
+            @test f(B) == f(A) * D
+            D = Diagonal(rand(size(A,2)))
+            B .= A
+            lmul!(D, f(B))
+            @test f(B) == D * f(A)
+        end
     end
 end
 

From a9ee0f59feabd19b57e970b2b712db86d49647c1 Mon Sep 17 00:00:00 2001
From: Jishnu Bhattacharya <jishnub.github@gmail.com>
Date: Wed, 26 Feb 2025 14:46:17 +0530
Subject: [PATCH 3/3] Test for complex Diagonal

---
 test/diagonal.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/diagonal.jl b/test/diagonal.jl
index 6f6bbabb..4675e6f2 100644
--- a/test/diagonal.jl
+++ b/test/diagonal.jl
@@ -1261,11 +1261,11 @@ end
     for T in (Float64, ComplexF64)
         A = rand(T,5,4); B = similar(A)
         for f in (adjoint, transpose)
-            D = Diagonal(rand(size(A,1)))
+            D = Diagonal(rand(T, size(A,1)))
             B .= A
             rmul!(f(B), D)
             @test f(B) == f(A) * D
-            D = Diagonal(rand(size(A,2)))
+            D = Diagonal(rand(T, size(A,2)))
             B .= A
             lmul!(D, f(B))
             @test f(B) == D * f(A)