Add easy_rule for matrix det

[kshyatt]

Something very odd going on with some of this.

• test_forward fails for the Matrix{ComplexF64} even though it's (secretly) all real valued
• test_reverse seems to be running the rule on each element of the matrix argument individually @sethaxen any ideas why?

[wsmoses]

use fill!(minorAij, zero) instead?

[codecov]

Codecov Report

❌ Patch coverage is 30.18868% with 37 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.87%. Comparing base (107b327) to head (f6b5a16).
⚠️ Report is 27 commits behind head on main.

Files with missing lines	Patch %	Lines
src/rules/customrules.jl	8.00%	23 Missing ⚠️
src/internal_rules.jl	6.66%	14 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2725      +/-   ##
==========================================
- Coverage   72.61%   69.87%   -2.75%     
==========================================
  Files          58       58              
  Lines       18746    19369     +623     
==========================================
- Hits        13613    13534      -79     
- Misses       5133     5835     +702     

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[github-actions]

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diff --git a/lib/EnzymeTestUtils/src/test_utils.jl b/lib/EnzymeTestUtils/src/test_utils.jl
index d111f537..820306bf 100644
--- a/lib/EnzymeTestUtils/src/test_utils.jl
+++ b/lib/EnzymeTestUtils/src/test_utils.jl
@@ -4,7 +4,7 @@ struct CallWithKWargs{KW}
 end
 
 function (c::CallWithKWargs)(f, xs...)
-    f(xs...; c.kwargs...)
+    return f(xs...; c.kwargs...)
 end
 
 struct CallWithCopyKWargs{KW}
@@ -12,9 +12,9 @@ struct CallWithCopyKWargs{KW}
 end
 
 function (c::CallWithCopyKWargs)(f, xs...)
-    deepcopy(f)(deepcopy(xs)...; deepcopy(c.kwargs)...)
+    return deepcopy(f)(deepcopy(xs)...; deepcopy(c.kwargs)...)
 end
 
 @inline function get_primal(x::Annotation)
-    x.val
-end
\ No newline at end of file
+    return x.val
+end
diff --git a/src/internal_rules.jl b/src/internal_rules.jl
index b359c670..a02d0e79 100644
--- a/src/internal_rules.jl
+++ b/src/internal_rules.jl
@@ -923,7 +923,7 @@ function EnzymeRules.reverse(
 end
 
 function cofactor(A)
-    cofA     = similar(A)
+    cofA = similar(A)
     minorAij = similar(A, size(A, 1) - 1, size(A, 2) - 1)
     for i in 1:size(A, 1), j in 1:size(A, 2)
         fill!(minorAij, zero(eltype(A)))
diff --git a/src/rules/customrules.jl b/src/rules/customrules.jl
index 415affb2..e83d73af 100644
--- a/src/rules/customrules.jl
+++ b/src/rules/customrules.jl
@@ -51,7 +51,7 @@ import LinearAlgebra
         elseif partial <: AbstractVector
             :(LinearAlgebra.dot(adjoint(partial),dx))
         else
-            :(LinearAlgebra.dot(conj(partial),dx))
+            :(LinearAlgebra.dot(conj(partial), dx))
         end
         return quote
             Base.@_inline_meta
@@ -109,27 +109,27 @@ import LinearAlgebra
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::Real, dx)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::Complex, dx)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Real}, dx::Number)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Complex}, dx::Number)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
 end
 
-@inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Real, N}, dx::AbstractArray{<:Any, N}) where N
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
+@inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Real, N}, dx::AbstractArray{<:Any, N}) where {N}
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, partial, dx)
 end
 
-@inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Complex, N}, dx::AbstractArray{<:Any, N}) where N
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
+@inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Complex, N}, dx::AbstractArray{<:Any, N}) where {N}
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, conj(partial), dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractVector{<:Complex}, dx::AbstractVector{<:Any})
@@ -137,21 +137,21 @@ end
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractMatrix{<:Real}, dx::AbstractVector)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, transpose(partial), dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, transpose(partial), dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractMatrix{<:Complex}, dx::AbstractVector)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, adjoint(partial), dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, adjoint(partial), dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Real}, dx::AbstractArray)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, Base.permutedims(partial, (((ndims(dx)+1):ndims(partial))..., Base.OneTo(ndims(dx))...)), dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, Base.permutedims(partial, (((ndims(dx) + 1):ndims(partial))..., Base.OneTo(ndims(dx))...)), dx)
 end
 
 @inline function EnzymeCore.EnzymeRules.multiply_rev_into(prev, partial::AbstractArray{<:Complex}, dx::AbstractArray)
-    pd = Base.permutedims(partial, (((ndims(dx)+1):ndims(partial))..., Base.OneTo(ndims(dx))...))
+    pd = Base.permutedims(partial, (((ndims(dx) + 1):ndims(partial))..., Base.OneTo(ndims(dx))...))
     Base.conj!(pd)
-    EnzymeCore.EnzymeRules.multiply_fwd_into(prev, pd, dx)
+    return EnzymeCore.EnzymeRules.multiply_fwd_into(prev, pd, dx)
 end
 
 function enzyme_custom_setup_args(
diff --git a/test/rules/internal_rules.jl b/test/rules/internal_rules.jl
index d9a60656..8ae1b8c2 100644
--- a/test/rules/internal_rules.jl
+++ b/test/rules/internal_rules.jl
@@ -210,17 +210,17 @@ end
 
 @testset "(matrix) det" begin
     @testset "forward" begin
-        @testset for RT in (Const,DuplicatedNoNeed,Duplicated,),
-                     Tx in (Const,Duplicated,)
+        @testset for RT in (Const, DuplicatedNoNeed, Duplicated),
+                Tx in (Const, Duplicated)
             xr = [4.0 3.0; 2.0 1.0]
             test_forward(LinearAlgebra.det, RT, (xr, Tx))
 
-            xc = [4.0+0.0im 3.0; 2.0-0.0im 1.0]
+            xc = [4.0 + 0.0im 3.0; 2.0 - 0.0im 1.0]
             test_forward(LinearAlgebra.det, RT, (xc, Tx))
         end
     end
     @testset "reverse" begin
-        @testset for RT in (Const, Active,), Tx in (Const, Duplicated,)
+        @testset for RT in (Const, Active), Tx in (Const, Duplicated)
 
             # TODO see https://github.com/EnzymeAD/Enzyme/issues/2537
             if RT <: Const
@@ -230,7 +230,7 @@ end
             x = [4.0 3.0; 2.0 1.0]
             test_reverse(LinearAlgebra.det, RT, (x, Tx))
 
-            x = [4.0+0.0im 3.0; 2.0-0.0im 1.0]
+            x = [4.0 + 0.0im 3.0; 2.0 - 0.0im 1.0]
             test_reverse(LinearAlgebra.det, RT, (x, Tx))
         end
     end

[wsmoses]

• test_forward fails for the Matrix{ComplexF64} even though it's (secretly) all real valued

So in this case it was actually testing complex [e.g. the random seeds had imag components], now fixed the complex failures from internal side

• test_reverse seems to be running the rule on each element of the matrix argument individually @sethaxen any ideas why?

so you were acidentally doing for x in [...] because of a trailing comma