From 5531f32614d5dac37f78451f9d4f288a602636c9 Mon Sep 17 00:00:00 2001
From: lxvm <lorenzo@vanmunoz.com>
Date: Mon, 12 Feb 2024 10:54:42 -0500
Subject: [PATCH 1/3] add test

---
 test/runtests.jl | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/test/runtests.jl b/test/runtests.jl
index 05908a6..02b7510 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -99,3 +99,8 @@ end
     buffer = hcubature_buffer(f,a,b)
     @test @inferred(hcubature(f,a,b;buffer=buffer))[1] ≈ (1+im)*sin(1)^2
 end
+
+@testset "issue 23" begin
+    @test hquadrature(x -> 1.0, 1, -1)[1] ≈ -2
+    @test hcubature(x -> 1.0, [-1,1], [1,-1])[1] ≈ -4
+end

From 9a3d4dc759ac8d276f3d91108456e93454cf3f1c Mon Sep 17 00:00:00 2001
From: lxvm <lorenzo@vanmunoz.com>
Date: Mon, 12 Feb 2024 10:54:55 -0500
Subject: [PATCH 2/3] allow sign in gauss-kronrod

---
 src/gauss-kronrod.jl | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/gauss-kronrod.jl b/src/gauss-kronrod.jl
index 1651b55..6db1b37 100644
--- a/src/gauss-kronrod.jl
+++ b/src/gauss-kronrod.jl
@@ -40,8 +40,7 @@ function (g::GaussKronrod{T})(f::F, a_::SVector{1}, b_::SVector{1}, norm=norm) w
             I′ += fx * g.wg[i>>1]
         end
     end
-    V = abs(Δ)
-    I *= V
-    I′ *= V
+    I *= Δ
+    I′ *= Δ
     return I, norm(I - I′), 1
 end

From 5e260f0360e2c942edbc93365dfd34bc8558c3ab Mon Sep 17 00:00:00 2001
From: lxvm <lorenzo@vanmunoz.com>
Date: Mon, 12 Feb 2024 10:55:10 -0500
Subject: [PATCH 3/3] allow sign in genz-malik

---
 src/genz-malik.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/genz-malik.jl b/src/genz-malik.jl
index c4881f0..3c0af85 100644
--- a/src/genz-malik.jl
+++ b/src/genz-malik.jl
@@ -115,7 +115,7 @@ to subdivide next.
 """
 function (g::GenzMalik{n,T})(f::F, a::SVector{n}, b::SVector{n}, norm=norm) where {F, n,T}
     c = T(0.5).*(a.+b)
-    Δ = T(0.5).*abs.(b.-a)
+    Δ = T(0.5).*(b.-a)
     V = prod(Δ)
 
     f₁ = f(c)
@@ -158,7 +158,7 @@ function (g::GenzMalik{n,T})(f::F, a::SVector{n}, b::SVector{n}, norm=norm) wher
         if (δ = divdiff[i] - maxdivdiff) > δf
             kdivide = i
             maxdivdiff = divdiff[i]
-        elseif abs(δ) <= δf && Δ[i] > Δ[kdivide]
+        elseif abs(δ) <= δf && abs(Δ[i]) > abs(Δ[kdivide])
             kdivide = i
         end
     end