From f35540bc0b9b78b6afde2029ac2d0fc3e5ab44be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20Mas=C3=B3?= <miguel.maso@upc.edu>
Date: Tue, 11 Nov 2025 14:57:56 +0100
Subject: [PATCH 1/3] faster cofactor

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

diff --git a/src/TensorAlgebra/Functions.jl b/src/TensorAlgebra/Functions.jl
index 782e8cd..3cdf3bf 100644
--- a/src/TensorAlgebra/Functions.jl
+++ b/src/TensorAlgebra/Functions.jl
@@ -17,7 +17,7 @@ end
 Calculate the cofactor of a matrix.
 """
 function cof(A::TensorValue)
-  return det(A)*inv(A')
+  0.5A×A
 end
 
 

From 72c25d94c934200d5607fdcbe59bb3589cb355da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20Mas=C3=B3?= <miguel.maso@upc.edu>
Date: Tue, 11 Nov 2025 14:58:35 +0100
Subject: [PATCH 2/3] rename + test

---
 .../{TensorAlgebra.jl => TensorAlgebraTests.jl}      | 10 +++++++++-
 test/TestTensorAlgebra/runtests.jl                   | 12 ++++++++----
 2 files changed, 17 insertions(+), 5 deletions(-)
 rename test/TestTensorAlgebra/{TensorAlgebra.jl => TensorAlgebraTests.jl} (95%)

diff --git a/test/TestTensorAlgebra/TensorAlgebra.jl b/test/TestTensorAlgebra/TensorAlgebraTests.jl
similarity index 95%
rename from test/TestTensorAlgebra/TensorAlgebra.jl
rename to test/TestTensorAlgebra/TensorAlgebraTests.jl
index 126ecfc..c84ecff 100644
--- a/test/TestTensorAlgebra/TensorAlgebra.jl
+++ b/test/TestTensorAlgebra/TensorAlgebraTests.jl
@@ -104,5 +104,13 @@ end
 @testset "sqrt" begin
   A = TensorValue(1.:9...)
   A = A'*A + I3
-  @test isapprox(sqrt(A), TensorValue(sqrt(get_array(A))), rtol=1e-14)
+  sqrtA = TensorValue(sqrt(get_array(A)))
+  @test isapprox(sqrt(A), sqrtA, rtol=1e-14)
+end
+
+
+@testset "cofactor" begin
+  A = TensorValue(1.:9...) + I3
+  cofA = det(A) * inv(A')
+  @test isapprox(cof(A), cofA)
 end
diff --git a/test/TestTensorAlgebra/runtests.jl b/test/TestTensorAlgebra/runtests.jl
index 7b354b0..7f3e541 100644
--- a/test/TestTensorAlgebra/runtests.jl
+++ b/test/TestTensorAlgebra/runtests.jl
@@ -1,7 +1,11 @@
+using HyperFEM
+using Gridap
+using Test
+
 @testset "TensorAlgebra" begin
 
-    @time begin
-        include("TensorAlgebra.jl")
-    end
+  @time begin
+    include("TensorAlgebraTests.jl")
+  end
 
-end
\ No newline at end of file
+end

From 122b58e48b202667d20eaa26b430b67a4dd39632 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miguel=20Mas=C3=B3?= <miguel.maso@upc.edu>
Date: Tue, 11 Nov 2025 14:58:50 +0100
Subject: [PATCH 3/3] added benchmark

---
 benchmark/TensorAlgebraBenchmarks/TensorAlgebraBenchmarks.jl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/benchmark/TensorAlgebraBenchmarks/TensorAlgebraBenchmarks.jl b/benchmark/TensorAlgebraBenchmarks/TensorAlgebraBenchmarks.jl
index 66342fc..7693540 100644
--- a/benchmark/TensorAlgebraBenchmarks/TensorAlgebraBenchmarks.jl
+++ b/benchmark/TensorAlgebraBenchmarks/TensorAlgebraBenchmarks.jl
@@ -42,5 +42,10 @@ function _δδ_λ_2D(λ::Float64)
     λ)
 end
 
+A = TensorValue(1.:9...)
+A = A + A' + I3
+
 SUITE["Tensor algebra"]["δδ_μ_2d"] = @benchmarkable δᵢₖδⱼₗ2D + δᵢₗδⱼₖ2D
 SUITE["Tensor algebra"]["δδ_λ_2d"] = @benchmarkable 1.0 * δᵢⱼδₖₗ2D
+SUITE["Tensor algebra"]["Cofactor"] = cof(A)
+SUITE["Tensor algebra"]["Det(A)Inv(A')"] = det(A)*inv(A')