From 42a07001bdcbe142b61dd624fd571125b0e811ce Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Thu, 6 Mar 2025 07:46:23 +0100
Subject: [PATCH 1/2] feat: make `dense_ad` act as the identity on a dense
 backend

---
 Project.toml   | 2 +-
 src/sparse.jl  | 4 +++-
 test/sparse.jl | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/Project.toml b/Project.toml
index 1f58616..76f78f5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ADTypes"
 uuid = "47edcb42-4c32-4615-8424-f2b9edc5f35b"
 authors = ["Vaibhav Dixit <vaibhavyashdixit@gmail.com>, Guillaume Dalle and contributors"]
-version = "1.13.0"
+version = "1.14.0"
 
 [deps]
 ChainRulesCore = "d360d2e6-b24c-11e9-a2a3-2a2ae2dbcce4"
diff --git a/src/sparse.jl b/src/sparse.jl
index 953c334..1b389c8 100644
--- a/src/sparse.jl
+++ b/src/sparse.jl
@@ -225,14 +225,16 @@ end
 
 """
     dense_ad(ad::AutoSparse)::AbstractADType
+    dense_ad(ad::AbstractADType)::AbstractADType
 
-Return the underlying AD package for a sparse AD choice.
+Return the underlying AD package for a sparse AD choice, acts as the identity on a dense AD choice.
 
 # See also
 
   - [`AutoSparse`](@ref)
 """
 dense_ad(ad::AutoSparse) = ad.dense_ad
+dense_ad(ad::AbstractADType) = ad
 
 mode(sparse_ad::AutoSparse) = mode(dense_ad(sparse_ad))
 
diff --git a/test/sparse.jl b/test/sparse.jl
index 10c1c01..0d9df5e 100644
--- a/test/sparse.jl
+++ b/test/sparse.jl
@@ -11,6 +11,7 @@
         elseif mode(ad) isa SymbolicMode
             @test mode(sparse_ad) isa SymbolicMode
         end
+        @test dense_ad(ad) == ad
         @test dense_ad(sparse_ad) == ad
         @test sparsity_detector(sparse_ad) == NoSparsityDetector()
         @test coloring_algorithm(sparse_ad) == NoColoringAlgorithm()

From 1a9d27d00871186ea2a9a786910afc7773b5b6e0 Mon Sep 17 00:00:00 2001
From: Guillaume Dalle <22795598+gdalle@users.noreply.github.com>
Date: Thu, 6 Mar 2025 07:48:12 +0100
Subject: [PATCH 2/2] Typo

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

diff --git a/src/sparse.jl b/src/sparse.jl
index 1b389c8..21dd8c6 100644
--- a/src/sparse.jl
+++ b/src/sparse.jl
@@ -227,7 +227,7 @@ end
     dense_ad(ad::AutoSparse)::AbstractADType
     dense_ad(ad::AbstractADType)::AbstractADType
 
-Return the underlying AD package for a sparse AD choice, acts as the identity on a dense AD choice.
+Return the underlying AD package for a sparse AD choice, act as the identity on a dense AD choice.
 
 # See also