From ccf1408420035fefa86f6fdea9dbfec61fc287c3 Mon Sep 17 00:00:00 2001
From: Frames White <me@oxinabox.net>
Date: Tue, 20 Feb 2024 12:03:20 +0800
Subject: [PATCH] add scaling division

---
 src/tangent_types/abstract_tangent.jl    |  3 +++
 test/tangent_types/structural_tangent.jl | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/tangent_types/abstract_tangent.jl b/src/tangent_types/abstract_tangent.jl
index 2f5d0a492..db346e8b8 100644
--- a/src/tangent_types/abstract_tangent.jl
+++ b/src/tangent_types/abstract_tangent.jl
@@ -38,3 +38,6 @@ abstract type AbstractTangent end
 Base.:+(x::AbstractTangent) = x
 
 @inline Base.conj(x::AbstractTangent) = x
+
+Base.:/(x::AbstractTangent, y) = x * inv(y)
+Base.:\(x, y::AbstractTangent) = inv(x) * y
\ No newline at end of file
diff --git a/test/tangent_types/structural_tangent.jl b/test/tangent_types/structural_tangent.jl
index d93487703..145c937b3 100644
--- a/test/tangent_types/structural_tangent.jl
+++ b/test/tangent_types/structural_tangent.jl
@@ -396,6 +396,19 @@ end
             @test_throws MethodError Tangent{Foo}(; y=1.5, x=2.5) * @thunk [1 2; 3 4]
         end
 
+        @testset "scaling division" end
+            a = Tangent{Foo}(; x=2.0, y=-2.0)
+            @test a / 2.0 == Tangent{Foo}(; x=1.0, y=-1.0) == 2.0 \ a
+            @test (
+                Tangent{Tuple{Float64,Float64}}(2.0, 4.0) / 2.0 ==
+                Tangent{Tuple{Float64,Float64}}(1.0, 2.0) ==
+                2.0 \ Tangent{Tuple{Float64,Float64}}(2.0, 4.0)
+            )
+
+
+        end
+
+
         @testset "iszero" begin
             @test iszero(Tangent{Foo}())
             @test iszero(Tangent{Tuple{}}())