From ccbb454b7552f6fca97f2cc607926b62cd9b4966 Mon Sep 17 00:00:00 2001
From: mtfishman <mfishman@flatironinstitute.org>
Date: Fri, 9 Jan 2026 17:09:40 -0500
Subject: [PATCH 1/2] Add permuteddims definitions for StridedViews and more
 FillArrays

---
 Project.toml                                  |  5 +++-
 .../FunctionImplementationsFillArraysExt.jl   | 26 ++++++++++++++++---
 .../FunctionImplementationsStridedViewsExt.jl | 11 ++++++++
 test/Project.toml                             |  2 ++
 test/test_fillarraysext.jl                    | 26 +++++++++++++++++++
 test/test_linearalgebraext.jl                 |  9 +++++++
 test/test_permuteddims.jl                     | 25 ++++--------------
 test/test_stridedviewsext.jl                  | 11 ++++++++
 8 files changed, 90 insertions(+), 25 deletions(-)
 create mode 100644 ext/FunctionImplementationsStridedViewsExt/FunctionImplementationsStridedViewsExt.jl
 create mode 100644 test/test_fillarraysext.jl
 create mode 100644 test/test_linearalgebraext.jl
 create mode 100644 test/test_stridedviewsext.jl

diff --git a/Project.toml b/Project.toml
index debf4cb..4f9cd4d 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,22 +1,25 @@
 name = "FunctionImplementations"
 uuid = "7c7cc465-9c6a-495f-bdd1-f42428e86d0c"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.3.1"
+version = "0.3.2"
 
 [weakdeps]
 BlockArrays = "8e7c35d0-a365-5155-bbbb-fb81a777f24e"
 FillArrays = "1a297f60-69ca-5386-bcde-b61e274b549b"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+StridedViews = "4db3bf67-4bd7-4b4e-b153-31dc3fb37143"
 
 [extensions]
 FunctionImplementationsBlockArraysExt = "BlockArrays"
 FunctionImplementationsFillArraysExt = "FillArrays"
 FunctionImplementationsLinearAlgebraExt = "LinearAlgebra"
+FunctionImplementationsStridedViewsExt = "StridedViews"
 
 [compat]
 BlockArrays = "1.4"
 FillArrays = "1.15"
 LinearAlgebra = "1.10"
+StridedViews = "0.4.1"
 julia = "1.10"
 
 [workspace]
diff --git a/ext/FunctionImplementationsFillArraysExt/FunctionImplementationsFillArraysExt.jl b/ext/FunctionImplementationsFillArraysExt/FunctionImplementationsFillArraysExt.jl
index 0a9fc1a..7ea8b8a 100644
--- a/ext/FunctionImplementationsFillArraysExt/FunctionImplementationsFillArraysExt.jl
+++ b/ext/FunctionImplementationsFillArraysExt/FunctionImplementationsFillArraysExt.jl
@@ -1,12 +1,30 @@
 module FunctionImplementationsFillArraysExt
 
-using FillArrays: RectDiagonal
-using FunctionImplementations: FunctionImplementations
+using FillArrays: FillArrays as FA, AbstractFill, RectDiagonal
+import FunctionImplementations as FI
 
-function FunctionImplementations.permuteddims(a::RectDiagonal, perm)
+function check_perm(a::AbstractArray, perm)
     (ndims(a) == length(perm) && isperm(perm)) ||
         throw(ArgumentError("no valid permutation of dimensions"))
-    return RectDiagonal(parent(a), ntuple(d -> axes(a)[perm[d]], ndims(a)))
+    return nothing
+end
+
+function perm_axes(a::AbstractArray, perm)
+    return ntuple(d -> axes(a)[perm[d]], ndims(a))
+end
+
+# This could call `permutedims` directly after
+# https://github.com/JuliaArrays/FillArrays.jl/pull/319 is merged.
+function FI.permuteddims(a::AbstractFill, perm)
+    check_perm(a, perm)
+    return FA.fillsimilar(parent(a), perm_axes(a, perm))
+end
+
+# This could call `permutedims` directly after
+# https://github.com/JuliaArrays/FillArrays.jl/issues/413 is fixed.
+function FI.permuteddims(a::RectDiagonal, perm)
+    check_perm(a, perm)
+    return RectDiagonal(parent(a), perm_axes(a, perm))
 end
 
 end
diff --git a/ext/FunctionImplementationsStridedViewsExt/FunctionImplementationsStridedViewsExt.jl b/ext/FunctionImplementationsStridedViewsExt/FunctionImplementationsStridedViewsExt.jl
new file mode 100644
index 0000000..251ba38
--- /dev/null
+++ b/ext/FunctionImplementationsStridedViewsExt/FunctionImplementationsStridedViewsExt.jl
@@ -0,0 +1,11 @@
+module FunctionImplementationsStridedViewsExt
+
+using FunctionImplementations: FunctionImplementations
+using StridedViews: StridedView
+
+# `permutedims` is lazy for `StridedView` so we can just call it directly.
+function FunctionImplementations.permuteddims(a::StridedView, perm)
+    return permutedims(a, perm)
+end
+
+end
diff --git a/test/Project.toml b/test/Project.toml
index c49bbae..b74165f 100644
--- a/test/Project.toml
+++ b/test/Project.toml
@@ -7,6 +7,7 @@ FunctionImplementations = "7c7cc465-9c6a-495f-bdd1-f42428e86d0c"
 JLArrays = "27aeb0d3-9eb9-45fb-866b-73c2ecf80fcb"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 SafeTestsets = "1bc83da4-3b8d-516f-aca4-4fe02f6d838f"
+StridedViews = "4db3bf67-4bd7-4b4e-b153-31dc3fb37143"
 Suppressor = "fd094767-a336-5f1f-9728-57cf17d0bbfb"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
@@ -22,5 +23,6 @@ FunctionImplementations = "0.3"
 JLArrays = "0.3"
 LinearAlgebra = "1.10"
 SafeTestsets = "0.1"
+StridedViews = "0.4"
 Suppressor = "0.2"
 Test = "1.10"
diff --git a/test/test_fillarraysext.jl b/test/test_fillarraysext.jl
new file mode 100644
index 0000000..213d342
--- /dev/null
+++ b/test/test_fillarraysext.jl
@@ -0,0 +1,26 @@
+import FillArrays as FA
+import FunctionImplementations as FI
+using Test: @test, @testset
+
+@testset "FillArraysExt" begin
+    @testset "Fill" begin
+        a = FA.Fill(42, (2, 3))
+        @test FI.permuteddims(a, (1, 2)) ≡ a
+        @test FI.permuteddims(a, (2, 1)) ≡ FA.Fill(42, (3, 2))
+    end
+    @testset "Zeros" begin
+        a = FA.Zeros((2, 3))
+        @test FI.permuteddims(a, (1, 2)) ≡ a
+        @test FI.permuteddims(a, (2, 1)) ≡ FA.Zeros((3, 2))
+    end
+    @testset "Ones" begin
+        a = FA.Ones((2, 3))
+        @test FI.permuteddims(a, (1, 2)) ≡ a
+        @test FI.permuteddims(a, (2, 1)) ≡ FA.Ones((3, 2))
+    end
+    @testset "RectDiagonal" begin
+        a = FA.RectDiagonal(randn(3), (3, 4))
+        @test FI.permuteddims(a, (1, 2)) ≡ a
+        @test FI.permuteddims(a, (2, 1)) ≡ FA.RectDiagonal(parent(a), (4, 3))
+    end
+end
diff --git a/test/test_linearalgebraext.jl b/test/test_linearalgebraext.jl
new file mode 100644
index 0000000..8fca0fc
--- /dev/null
+++ b/test/test_linearalgebraext.jl
@@ -0,0 +1,9 @@
+import FunctionImplementations as FI
+import LinearAlgebra as LA
+using Test: @test, @testset
+
+@testset "LinearAlgebraExt" begin
+    a = LA.Diagonal(randn(3))
+    b = FI.permuteddims(a, (2, 1))
+    @test b ≡ a
+end
diff --git a/test/test_permuteddims.jl b/test/test_permuteddims.jl
index 07e4a4d..fe1d777 100644
--- a/test/test_permuteddims.jl
+++ b/test/test_permuteddims.jl
@@ -1,25 +1,10 @@
-import FillArrays as FA
 import FunctionImplementations as FI
-import LinearAlgebra as LA
 using Test: @test, @testset
 
 @testset "permuteddims" begin
-    @testset "Array" begin
-        a = randn(2, 3)
-        b = FI.permuteddims(a, (2, 1))
-        @test b ≡ PermutedDimsArray(a, (2, 1))
-        @test size(b) == (3, 2)
-        @test b == permutedims(a, (2, 1))
-    end
-    @testset "LinearAlgebra.Diagonal" begin
-        a = LA.Diagonal(randn(3))
-        b = FI.permuteddims(a, (2, 1))
-        @test b ≡ a
-    end
-
-    @testset "FillArrays.RectDiagonal" begin
-        a = FA.RectDiagonal(randn(3), (3, 4))
-        @test FI.permuteddims(a, (1, 2)) ≡ a
-        @test FI.permuteddims(a, (2, 1)) ≡ FA.RectDiagonal(parent(a), (4, 3))
-    end
+    a = randn(2, 3)
+    b = FI.permuteddims(a, (2, 1))
+    @test b ≡ PermutedDimsArray(a, (2, 1))
+    @test size(b) == (3, 2)
+    @test b == permutedims(a, (2, 1))
 end
diff --git a/test/test_stridedviewsext.jl b/test/test_stridedviewsext.jl
new file mode 100644
index 0000000..2814c6f
--- /dev/null
+++ b/test/test_stridedviewsext.jl
@@ -0,0 +1,11 @@
+import FunctionImplementations as FI
+import StridedViews as SV
+using Test: @test, @testset
+
+@testset "StridedViewsExt" begin
+    a = SV.StridedView(randn(2, 3, 4))
+    b = FI.permuteddims(a, (3, 2, 1))
+    @test b isa SV.StridedView
+    @test size(b) == (4, 3, 2)
+    @test b ≡ permutedims(a, (3, 2, 1))
+end
\ No newline at end of file

From 2618ff500aaf0d492eb2652eaa624e6086dd00a9 Mon Sep 17 00:00:00 2001
From: mtfishman <mfishman@flatironinstitute.org>
Date: Fri, 9 Jan 2026 17:14:15 -0500
Subject: [PATCH 2/2] Format

---
 test/test_stridedviewsext.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_stridedviewsext.jl b/test/test_stridedviewsext.jl
index 2814c6f..b40d6df 100644
--- a/test/test_stridedviewsext.jl
+++ b/test/test_stridedviewsext.jl
@@ -8,4 +8,4 @@ using Test: @test, @testset
     @test b isa SV.StridedView
     @test size(b) == (4, 3, 2)
     @test b ≡ permutedims(a, (3, 2, 1))
-end
\ No newline at end of file
+end