From a56322f64aba7c92fb23a5afb3bea064f7cdd042 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:12:14 +0000
Subject: [PATCH 01/46] Support Eigen 5

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5851511..bb3efb8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,7 @@ find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 find_package(pybind11 CONFIG REQUIRED)
 
 # Find Eigen 3.4+
-find_package(Eigen3 3.4 REQUIRED)
+find_package(Eigen3 3.4...5 REQUIRED)
 
 # Add project sources to python module
 file(GLOB SOURCES src/*.cpp)

From 5b953feeeb63afcdeaf7163f9f7054c76e606267 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:12:20 +0000
Subject: [PATCH 02/46] Update cibuildhweel action

---
 .github/workflows/build_wheels.yml | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index b68cae5..54b4660 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -14,20 +14,19 @@ jobs:
     strategy:
       matrix:
         # Note: builds on these are backward compatible
-        # macos-13 is an intel runner, macos-14 is apple silicon
-        os: [ubuntu-latest, macos-13, macos-14, windows-latest]
+        os: [ubuntu-latest, macos-15-intel, macos-15, windows-latest]
 
     steps:
       - uses: actions/checkout@v4
 
       - name: Build wheels
-        uses: pypa/cibuildwheel@v2.23.3
+        uses: pypa/cibuildwheel@v4.2.1
         # to supply options, put them in 'env', like:
         # env:
         #   CIBW_SOME_OPTION: value
         env:
           # List of platforms to build on
-          CIBW_BUILD: cp3{10,11,12,13}-manylinux_x86_64 cp3{10,11,12,13}-macosx_x86_64 cp3{10,11,12,13}-macosx_arm64 cp3{10,11,12,13}-win_amd64
+          CIBW_BUILD: cp3{10,11,12,13,14}-manylinux_x86_64 cp3{10,11,12,13,14}-macosx_x86_64 cp3{10,11,12,13,14}-macosx_arm64 cp3{10,11,12,13,14}-win_amd64
 
           # Install Eigen and pybind11 on manylinux images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_LINUX: >

From 9c262ff7ab9b5cb530dbf4aeba032f18ab0d3db1 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:23:21 +0000
Subject: [PATCH 03/46] [CI] Find Eigen

---
 .github/workflows/test.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 51e670e..69b8a0c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.10","3.11","3.12","3.13"]
+        python-version: ["3.10","3.11","3.12","3.13","3.14"]
 
     steps:
     - uses: actions/checkout@v4
@@ -28,6 +28,7 @@ jobs:
       run: |
         eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
         brew install eigen pybind11
+        export CMAKE_PREFIX_PATH="/home/linuxbrew/.linuxbrew/opt/eigen"
         pip install .
     - name: Tests
       run: |

From 352ea3eb577e66a6bb434382d966301eac77d1a8 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:25:02 +0000
Subject: [PATCH 04/46] [CI] Find Eigen differently

---
 .github/workflows/test.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 69b8a0c..6c3695c 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -28,7 +28,7 @@ jobs:
       run: |
         eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
         brew install eigen pybind11
-        export CMAKE_PREFIX_PATH="/home/linuxbrew/.linuxbrew/opt/eigen"
+        export Eigen3_DIR="/home/linuxbrew/.linuxbrew/opt/eigen/share/eigen3/cmake"
         pip install .
     - name: Tests
       run: |

From 65919b596511d65433f21d2bab66a2d6b6a0866e Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:29:44 +0000
Subject: [PATCH 05/46] [CI] Try to find Eigen again...

---
 .github/workflows/test.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6c3695c..fc7cff9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -28,8 +28,10 @@ jobs:
       run: |
         eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
         brew install eigen pybind11
-        export Eigen3_DIR="/home/linuxbrew/.linuxbrew/opt/eigen/share/eigen3/cmake"
-        pip install .
+        export CPLUS_INCLUDE_PATH="/home/linuxbrew/.linuxbrew/opt/eigen/include/eigen3:$CPLUS_INCLUDE_PATH"
+        export CMAKE_PREFIX_PATH="/home/linuxbrew/.linuxbrew/opt/eigen"
+        export CMAKE_ARGS="-DCMAKE_PREFIX_PATH=/home/linuxbrew/.linuxbrew/opt/eigen"
+        pip install . --no-build-isolation
     - name: Tests
       run: |
         pip install numpy --only-binary=numpy

From 78487944901826d273866e4e8a8c74462e3b1473 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:31:19 +0000
Subject: [PATCH 06/46] [CI] And again...

---
 .github/workflows/test.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fc7cff9..1e5cbff 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -31,7 +31,7 @@ jobs:
         export CPLUS_INCLUDE_PATH="/home/linuxbrew/.linuxbrew/opt/eigen/include/eigen3:$CPLUS_INCLUDE_PATH"
         export CMAKE_PREFIX_PATH="/home/linuxbrew/.linuxbrew/opt/eigen"
         export CMAKE_ARGS="-DCMAKE_PREFIX_PATH=/home/linuxbrew/.linuxbrew/opt/eigen"
-        pip install . --no-build-isolation
+        pip install .
     - name: Tests
       run: |
         pip install numpy --only-binary=numpy

From cafd5c6addca916991590ca605b92435fedef28e Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:43:42 +0000
Subject: [PATCH 07/46] Support Eigen 5 all

---
 src/findiff.h    | 7 +++++++
 src/lhs.h        | 7 +++++++
 src/multistart.h | 7 +++++++
 3 files changed, 21 insertions(+)

diff --git a/src/findiff.h b/src/findiff.h
index 88c7056..c9bb7dc 100644
--- a/src/findiff.h
+++ b/src/findiff.h
@@ -14,6 +14,13 @@
 #include <functional>
 #include <Eigen/Core>
 
+// Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
+#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+namespace Eigen {
+    using namespace Eigen::placeholders;
+}
+#endif
+
 /*
  * Forward finite difference approximation to the Jacobian
  *
diff --git a/src/lhs.h b/src/lhs.h
index 98b83fc..0205749 100644
--- a/src/lhs.h
+++ b/src/lhs.h
@@ -14,6 +14,13 @@
 
 #include <Eigen/Core>
 
+// Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
+#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+namespace Eigen {
+    using namespace Eigen::placeholders;
+}
+#endif
+
 /*
  * Generate Latin Hypercube Design on [0,1]^n
  *
diff --git a/src/multistart.h b/src/multistart.h
index 5f21156..5732307 100644
--- a/src/multistart.h
+++ b/src/multistart.h
@@ -13,6 +13,13 @@
 
 #include "regularisation.h"
 
+// Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
+#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+namespace Eigen {
+    using namespace Eigen::placeholders;
+}
+#endif
+
 /*
  * Multistart adaptive quadratic regularisation
  *

From 5c258abbc98181606dc8b9997b419c2b1df885bf Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:52:03 +0000
Subject: [PATCH 08/46] Simplify macros

---
 src/findiff.h    | 2 +-
 src/lhs.h        | 2 +-
 src/multistart.h | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/findiff.h b/src/findiff.h
index c9bb7dc..b347054 100644
--- a/src/findiff.h
+++ b/src/findiff.h
@@ -15,7 +15,7 @@
 #include <Eigen/Core>
 
 // Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
-#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+#if EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4
 namespace Eigen {
     using namespace Eigen::placeholders;
 }
diff --git a/src/lhs.h b/src/lhs.h
index 0205749..9857402 100644
--- a/src/lhs.h
+++ b/src/lhs.h
@@ -15,7 +15,7 @@
 #include <Eigen/Core>
 
 // Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
-#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+#if EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4
 namespace Eigen {
     using namespace Eigen::placeholders;
 }
diff --git a/src/multistart.h b/src/multistart.h
index 5732307..e174b38 100644
--- a/src/multistart.h
+++ b/src/multistart.h
@@ -14,7 +14,7 @@
 #include "regularisation.h"
 
 // Eigen 5.0 moved all to the placeholders namespace to prevent global name clashes
-#if EIGEN_WORLD_VERSION >= 5 || (EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4)
+#if EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION > 4
 namespace Eigen {
     using namespace Eigen::placeholders;
 }

From 34d5f6f2873d7cba54ab79eb73ebe07af081dac2 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 10:58:11 +0000
Subject: [PATCH 09/46] [CI] use system Eigen on manylinux

---
 .github/workflows/build_wheels.yml | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 54b4660..98be04b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -28,19 +28,8 @@ jobs:
           # List of platforms to build on
           CIBW_BUILD: cp3{10,11,12,13,14}-manylinux_x86_64 cp3{10,11,12,13,14}-macosx_x86_64 cp3{10,11,12,13,14}-macosx_arm64 cp3{10,11,12,13,14}-win_amd64
 
-          # Install Eigen and pybind11 on manylinux images (no brew, need Eigen >= 3.4)
-          CIBW_BEFORE_ALL_LINUX: >
-            sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-* &&
-            sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-* &&
-            yum install -y wget &&
-            wget https://gitlab.com/libeigen/eigen/-/archive/3.4.0/eigen-3.4.0.tar.gz &&
-            tar xzf eigen-3.4.0.tar.gz &&
-            cd eigen-3.4.0 &&
-            mkdir build &&
-            cd build &&
-            cmake .. &&
-            make install &&
-            cd ../..
+          # Install Eigen and pybind11 on manylinux images
+          CIBW_BEFORE_ALL_LINUX: yum install -y eigen3-devel
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From 8fda001257c3e15e3b3a7c3256e2f774c1824dd4 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:02:09 +0000
Subject: [PATCH 10/46] Drop unsupported license classifier

---
 setup.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/setup.py b/setup.py
index 76e0aee..5e0f49f 100644
--- a/setup.py
+++ b/setup.py
@@ -132,7 +132,7 @@ def build_extension(self, ext):
         "Documentation": "https://ralna.github.io/GOFit/",
         "Source Code": "https://github.com/ralna/gofit/",
     },
-    license='New BSD',
+    license='BSD-3-Clause',
     keywords = "mathematics optimization",
     classifiers=[
         'Development Status :: 5 - Production/Stable',
@@ -140,7 +140,6 @@ def build_extension(self, ext):
         'Framework :: IPython',
         'Framework :: Jupyter',
         'Intended Audience :: Science/Research',
-        'License :: OSI Approved :: BSD License',
         'Operating System :: Unix',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',

From 779619ad4faf34c38e4b54bc627834aa5a6fa988 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:05:38 +0000
Subject: [PATCH 11/46] [CI] Add include path for macOS

---
 .github/workflows/build_wheels.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 98be04b..e62aead 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -34,6 +34,7 @@ jobs:
 
           # Install Eigen and pybind11 on macOS
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
+          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3'"
 
           # Install Eigen and pybind11 on Windows
           CIBW_BEFORE_ALL_WINDOWS: choco install eigen

From 4d132b1bb85ac3ca166f22eb5f67b5d8faa2b25c Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:11:45 +0000
Subject: [PATCH 12/46] [CI] Pull in latest Eigen for Linux

---
 .github/workflows/build_wheels.yml | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index e62aead..559671c 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -28,8 +28,17 @@ jobs:
           # List of platforms to build on
           CIBW_BUILD: cp3{10,11,12,13,14}-manylinux_x86_64 cp3{10,11,12,13,14}-macosx_x86_64 cp3{10,11,12,13,14}-macosx_arm64 cp3{10,11,12,13,14}-win_amd64
 
-          # Install Eigen and pybind11 on manylinux images
-          CIBW_BEFORE_ALL_LINUX: yum install -y eigen3-devel
+          # Install Eigen and pybind11 on manylinux images (no brew, need Eigen >= 3.4)
+          CIBW_BEFORE_ALL_LINUX: >
+            yum install -y wget &&
+            wget https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz &&
+            tar xzf eigen-5.0.1.tar.gz &&
+            cd eigen-5.0.1 &&
+            mkdir build &&
+            cd build &&
+            cmake .. &&
+            make install &&
+            cd ../..
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From 83d28a94fb9ab068d08fa1af9448400660bb854e Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:28:12 +0000
Subject: [PATCH 13/46] [CI] Install Eigen 5 on Windows

---
 .github/workflows/build_wheels.yml | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 559671c..3210763 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -45,8 +45,16 @@ jobs:
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
           CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3'"
 
-          # Install Eigen and pybind11 on Windows
-          CIBW_BEFORE_ALL_WINDOWS: choco install eigen
+          # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
+          CIBW_BEFORE_ALL_WINDOWS: """
+            powershell -Command "\
+            Invoke-WebRequest \
+              -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip \
+              -OutFile eigen.zip; \
+            Expand-Archive eigen.zip -DestinationPath C:\\eigen; \
+            Move-Item C:\\eigen\\eigen-5.0.1 C:\\eigen\\include\
+            "
+          """
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From d50d675dc398fd800f5ee232d2b1ef0684201bdf Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:35:46 +0000
Subject: [PATCH 14/46] [CI] Fix syntax

---
 .github/workflows/build_wheels.yml | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 3210763..1ba063b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -46,15 +46,8 @@ jobs:
           CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3'"
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
-          CIBW_BEFORE_ALL_WINDOWS: """
-            powershell -Command "\
-            Invoke-WebRequest \
-              -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip \
-              -OutFile eigen.zip; \
-            Expand-Archive eigen.zip -DestinationPath C:\\eigen; \
-            Move-Item C:\\eigen\\eigen-5.0.1 C:\\eigen\\include\
-            "
-          """
+          CIBW_BEFORE_ALL_WINDOWS: |
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen; Move-Item C:\eigen\eigen-5.0.1 C:\eigen\include"
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 575c0c3c8865a5b69724585e865914d570198c1a Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 11:44:18 +0000
Subject: [PATCH 15/46] [CI] Find eigen on Intel macs

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 1ba063b..4e55130 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -43,7 +43,7 @@ jobs:
 
           # Install Eigen and pybind11 on macOS
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
-          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3'"
+          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3:/usr/local/include/eigen3'"
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |

From d3730db4d33c01b65c29fc64505d3c14e15dee97 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:22:24 +0000
Subject: [PATCH 16/46] [CI] Find eigen on Windows

---
 .github/workflows/build_wheels.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 4e55130..6d13268 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,6 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen; Move-Item C:\eigen\eigen-5.0.1 C:\eigen\include"
+          CIBW_ENVIRONMENT_WINDOWS: 'INCLUDE="C:\eigen\include;\$INCLUDE"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 9a5e981c0dd70c3f0bf1e0162eaf92ad1c7f5c84 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:30:57 +0000
Subject: [PATCH 17/46] [CI] Try again...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 6d13268..d2e52a4 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -43,12 +43,12 @@ jobs:
 
           # Install Eigen and pybind11 on macOS
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
-          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3:/usr/local/include/eigen3'"
+          CIBW_ENVIRONMENT_MACOS: 'CMAKE_PREFIX_PATH="$(brew --prefix)"'
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen; Move-Item C:\eigen\eigen-5.0.1 C:\eigen\include"
-          CIBW_ENVIRONMENT_WINDOWS: 'INCLUDE="C:\eigen\include;\$INCLUDE"'
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 0118a7e3f31fceb2d2f470c3ae310a0a2e684041 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:34:10 +0000
Subject: [PATCH 18/46] [CI] Trying to be too clever...

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index d2e52a4..3e553c0 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -43,7 +43,7 @@ jobs:
 
           # Install Eigen and pybind11 on macOS
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
-          CIBW_ENVIRONMENT_MACOS: 'CMAKE_PREFIX_PATH="$(brew --prefix)"'
+          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3:/usr/local/include/eigen3'"
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |

From d42e9fc5cbd4fe300788e1e8aef207570816e5ff Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:40:45 +0000
Subject: [PATCH 19/46] [CI] I hate Windows...

---
 .github/workflows/build_wheels.yml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 3e553c0..7ac013b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,7 +47,12 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen; Move-Item C:\eigen\eigen-5.0.1 C:\eigen\include"
+            powershell -Command " `
+              Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; `
+              Expand-Archive eigen.zip -DestinationPath C:\eigen-src; `
+              cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen; `
+              cmake --install C:\eigen-build `
+            "
           CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 

From 807276127f0add698aa6c7039af64b3839f1aeac Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:45:17 +0000
Subject: [PATCH 20/46] [CI] And powershell...

---
 .github/workflows/build_wheels.yml | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 7ac013b..df198f6 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,12 +47,12 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command " `
-              Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; `
-              Expand-Archive eigen.zip -DestinationPath C:\eigen-src; `
-              cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen; `
-              cmake --install C:\eigen-build `
-            "
+            powershell -Command {
+              Invoke-WebRequest -Uri "https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip" -OutFile "eigen.zip"
+              Expand-Archive -Path "eigen.zip" -DestinationPath "C:\eigen-src"
+              cmake -S "C:\eigen-src\eigen-5.0.1" -B "C:\eigen-build" -DCMAKE_INSTALL_PREFIX="C:\eigen"
+              cmake --install "C:\eigen-build"
+            }
           CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 

From f346534d2642fe0e7c418ae8c7789d26e3718062 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:49:37 +0000
Subject: [PATCH 21/46] [CI] ...

---
 .github/workflows/build_wheels.yml | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index df198f6..8225c72 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,12 +47,7 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command {
-              Invoke-WebRequest -Uri "https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip" -OutFile "eigen.zip"
-              Expand-Archive -Path "eigen.zip" -DestinationPath "C:\eigen-src"
-              cmake -S "C:\eigen-src\eigen-5.0.1" -B "C:\eigen-build" -DCMAKE_INSTALL_PREFIX="C:\eigen"
-              cmake --install "C:\eigen-build"
-            }
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen; cmake --install C:\eigen-build"
           CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 

From f872eac94f57ca32aabc031559aa6757e08c83a6 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:54:25 +0000
Subject: [PATCH 22/46] [CI] Fix Eigen install on Windows

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 8225c72..4594c61 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,7 +47,7 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen; cmake --install C:\eigen-build"
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_PKGCONFIG=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
           CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 

From 2b32bd43c612f7482a0b1ab86c19256b588edc10 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 12:59:37 +0000
Subject: [PATCH 23/46] [CI] Fix Eigen install on Windows again

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 4594c61..719f35e 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,7 +47,7 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_PKGCONFIG=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
           CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 

From 8b98f59051e44c8fb5209b8d537f345fdb842b05 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 13:55:53 +0000
Subject: [PATCH 24/46] [CI] Getting there...

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 719f35e..a209d2d 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,7 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen" INCLUDE="C:\eigen\include\eigen3;\$INCLUDE"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 9126e54eccb441a3d9ecfe77352e6eb741135910 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:00:02 +0000
Subject: [PATCH 25/46] [CI] Almost...

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index a209d2d..1b1a64b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,7 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen" INCLUDE="C:\eigen\include\eigen3;\$INCLUDE"'
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen" CMAKE_INCLUDE_PATH="C:\eigen\include\eigen3"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From df7e76fbb35a8303fa833b7296e0b269a48c393e Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:08:09 +0000
Subject: [PATCH 26/46] [CI] I Think...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 1b1a64b..5ca549e 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen" CMAKE_INCLUDE_PATH="C:\eigen\include\eigen3"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; New-Item -ItemType Junction -Path C:\eigen\include\Eigen -Target C:\eigen\include\eigen3\Eigen"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 6e9ca59dc71757ecc28dd195c157940e8c2cd5e2 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:16:53 +0000
Subject: [PATCH 27/46] [CI] Maybe...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 5ca549e..6b03aee 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; New-Item -ItemType Junction -Path C:\eigen\include\Eigen -Target C:\eigen\include\eigen3\Eigen"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=./eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install eigen-build"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 7258da1f6546794154fbf29bf7e85dd8c80ea026 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:22:48 +0000
Subject: [PATCH 28/46] [CI] Or maybe not...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 6b03aee..2c52b50 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=./eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; New-Item -ItemType Directory -Path .\eigen-local\include; Move-Item .\eigen-5.0.1\Eigen .\eigen-local\include\Eigen; Move-Item .\eigen-5.0.1\cmake .\eigen-local\cmake"
+          CIBW_ENVIRONMENT_WINDOWS: 'Eigen3_DIR="eigen-local/cmake" CMAKE_INCLUDE_PATH="eigen-local/include"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 6bfeef3b641aa2fb3b7af2b3ea1f1fb67c106fe1 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:28:56 +0000
Subject: [PATCH 29/46] [CI] Definitely not...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 2c52b50..742c8e2 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; New-Item -ItemType Directory -Path .\eigen-local\include; Move-Item .\eigen-5.0.1\Eigen .\eigen-local\include\Eigen; Move-Item .\eigen-5.0.1\cmake .\eigen-local\cmake"
-          CIBW_ENVIRONMENT_WINDOWS: 'Eigen3_DIR="eigen-local/cmake" CMAKE_INCLUDE_PATH="eigen-local/include"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=.\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From eb8f2f541de0fa8f5cbee7a4c78c0b88c42d6656 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:39:34 +0000
Subject: [PATCH 30/46] [CI] Told you...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 742c8e2..ba7fbc1 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=.\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; New-Item -ItemType Directory -Path .\eigen-local\include; Move-Item .\eigen-5.0.1\Eigen .\eigen-local\include\Eigen; New-Item -ItemType Directory -Path .\cmake; Set-Content -Path .\cmake\FindEigen3.cmake -Value 'add_library(Eigen3::Eigen INTERFACE IMPORTED) \n set_target_properties(Eigen3::Eigen PROPERTIES INTERFACE_INCLUDE_DIRECTORIES \"\${CMAKE_CURRENT_SOURCE_DIR}/eigen-local/include\")'"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_MODULE_PATH="cmake"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 53614cb63fa18047cda46cd09541f77056b38c8f Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:49:39 +0000
Subject: [PATCH 31/46] [CI] Hmmm...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index ba7fbc1..9ea96cf 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath .; New-Item -ItemType Directory -Path .\eigen-local\include; Move-Item .\eigen-5.0.1\Eigen .\eigen-local\include\Eigen; New-Item -ItemType Directory -Path .\cmake; Set-Content -Path .\cmake\FindEigen3.cmake -Value 'add_library(Eigen3::Eigen INTERFACE IMPORTED) \n set_target_properties(Eigen3::Eigen PROPERTIES INTERFACE_INCLUDE_DIRECTORIES \"\${CMAKE_CURRENT_SOURCE_DIR}/eigen-local/include\")'"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_MODULE_PATH="cmake"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=.\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Move-Item .\eigen-install\include\eigen3\Eigen .\eigen-install\include\Eigen;  (Get-Content .\eigen-install\share\eigen3\cmake\Eigen3Targets.cmake) -replace '/include/eigen3', '/include' | Set-Content .\eigen-install\share\eigen3\cmake\Eigen3Targets.cmake "
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 45a2a8e221cd9bbba52ae30491457b5bd822ddcb Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 14:57:28 +0000
Subject: [PATCH 32/46] [CI] Right...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 9ea96cf..9aed0e8 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=.\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Move-Item .\eigen-install\include\eigen3\Eigen .\eigen-install\include\Eigen;  (Get-Content .\eigen-install\share\eigen3\cmake\Eigen3Targets.cmake) -replace '/include/eigen3', '/include' | Set-Content .\eigen-install\share\eigen3\cmake\Eigen3Targets.cmake "
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="eigen-install"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Move-Item C:\eigen-install\include\eigen3\Eigen C:\eigen-install\include\Eigen"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen-install" Eigen3_DIR="C:\eigen-install\share\eigen3\cmake" CMAKE_INCLUDE_PATH="C:\eigen-install\include"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 2e024adc4b3f4fc52a4d611ceadf990e70d45304 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:06:59 +0000
Subject: [PATCH 33/46] [CI] More promising...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 9aed0e8..8456514 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Move-Item C:\eigen-install\include\eigen3\Eigen C:\eigen-install\include\Eigen"
-          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_PREFIX_PATH="C:\eigen-install" Eigen3_DIR="C:\eigen-install\share\eigen3\cmake" CMAKE_INCLUDE_PATH="C:\eigen-install\include"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
+          CIBW_CONFIG_SETTINGS_WINDOWS: "cmake.args=-DCMAKE_PREFIX_PATH=C:\\eigen-install -DCMAKE_INCLUDE_PATH=C:\\eigen-install\\include\\eigen3"
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 95bf6f7c15df98600212b0bed9fe4d4fa33953e1 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:14:20 +0000
Subject: [PATCH 34/46] [CI] Even more promising...

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 8456514..9a5d62f 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,7 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_CONFIG_SETTINGS_WINDOWS: "cmake.args=-DCMAKE_PREFIX_PATH=C:\\eigen-install -DCMAKE_INCLUDE_PATH=C:\\eigen-install\\include\\eigen3"
+          CIBW_ENVIRONMENT_WINDOWS: 'CL="/I C:\eigen-install\include\eigen3"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 6a19baa08204687605460a62c7bb3ac08d54bc4c Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:20:35 +0000
Subject: [PATCH 35/46] [CI] Seriously? It was this simple??

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 9a5d62f..026c996 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,7 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CL="/I C:\eigen-install\include\eigen3"'
+          CIBW_ENVIRONMENT_WINDOWS: "INCLUDE=C:\\eigen-install\\include\\eigen3"
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From d84e98c354c7fd38a3f0b265ba6bebcbcdad2fdd Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:30:14 +0000
Subject: [PATCH 36/46] [CI] It was that simple

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 026c996..86f040f 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -48,7 +48,7 @@ jobs:
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
             powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: "INCLUDE=C:\\eigen-install\\include\\eigen3"
+          CIBW_ENVIRONMENT_WINDOWS: 'CXXFLAGS="/I C:\eigen-install\include\eigen3"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 35746dd5cd9ae0557e30d22d5e489803a6218c25 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:43:25 +0000
Subject: [PATCH 37/46] [CI] Of course it was not...

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 86f040f..c053892 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -47,8 +47,8 @@ jobs:
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build"
-          CIBW_ENVIRONMENT_WINDOWS: 'CXXFLAGS="/I C:\eigen-install\include\eigen3"'
+            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Set-Content -Path .\CMakeInitialCache.cmake -Value 'set(CMAKE_PREFIX_PATH \"C:/eigen-install\" CACHE PATH \"\" FORCE) \n set(CMAKE_INCLUDE_PATH \"C:/eigen-install/include/eigen3\" CACHE PATH \"\" FORCE)'"
+          CIBW_CONFIG_SETTINGS_WINDOWS: "cmake.args=-C;CMakeInitialCache.cmake"
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From 606fec2d5063d4429ef05fff671e03076a5736e5 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:48:58 +0000
Subject: [PATCH 38/46] [CI] Try chocolatey...

---
 .github/workflows/build_wheels.yml | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index c053892..8d649c0 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -46,9 +46,8 @@ jobs:
           CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3:/usr/local/include/eigen3'"
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
-          CIBW_BEFORE_ALL_WINDOWS: |
-            powershell -Command "Invoke-WebRequest -Uri https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.zip -OutFile eigen.zip; Expand-Archive eigen.zip -DestinationPath C:\eigen-src; cmake -S C:\eigen-src\eigen-5.0.1 -B C:\eigen-build -DCMAKE_INSTALL_PREFIX=C:\eigen-install -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF; cmake --install C:\eigen-build; Set-Content -Path .\CMakeInitialCache.cmake -Value 'set(CMAKE_PREFIX_PATH \"C:/eigen-install\" CACHE PATH \"\" FORCE) \n set(CMAKE_INCLUDE_PATH \"C:/eigen-install/include/eigen3\" CACHE PATH \"\" FORCE)'"
-          CIBW_CONFIG_SETTINGS_WINDOWS: "cmake.args=-C;CMakeInitialCache.cmake"
+          CIBW_BEFORE_ALL_WINDOWS: "choco install eigen -y"
+          CIBW_ENVIRONMENT_WINDOWS: 'CMAKE_ARGS="-DCMAKE_PREFIX_PATH=C:\ProgramData\chocolatey\lib\eigen -DCMAKE_INCLUDE_PATH=C:\ProgramData\chocolatey\lib\eigen\include\eigen3"'
           CIBW_BEFORE_BUILD_WINDOWS: pip install pybind11[global] delvewheel
 
           # cibuildwheel doesn't yet ship a default repair command for Windows

From b2fb4de5bdab3e6c79ca93ba1868d7456b9ee051 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:54:25 +0000
Subject: [PATCH 39/46] Fix CMakelists.txt

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb3efb8..5851511 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,7 @@ find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 find_package(pybind11 CONFIG REQUIRED)
 
 # Find Eigen 3.4+
-find_package(Eigen3 3.4...5 REQUIRED)
+find_package(Eigen3 3.4 REQUIRED)
 
 # Add project sources to python module
 file(GLOB SOURCES src/*.cpp)

From 8231b006497363086467226ad97edf00bdbe7af8 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 15:59:47 +0000
Subject: [PATCH 40/46] Fix CMakelists.txt again

---
 CMakeLists.txt | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5851511..69e04a9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -11,7 +11,10 @@ find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 find_package(pybind11 CONFIG REQUIRED)
 
 # Find Eigen 3.4+
-find_package(Eigen3 3.4 REQUIRED)
+find_package(Eigen3 REQUIRED)
+if(Eigen3_VERSION VERSION_LESS "3.4.0")
+    message(FATAL_ERROR "Eigen3 version ${Eigen3_VERSION} is too old. GOFit requires at least version 3.4")
+endif()
 
 # Add project sources to python module
 file(GLOB SOURCES src/*.cpp)

From 596e5ccf5790d8c85f4d073bbde27208c75a0992 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:12:59 +0000
Subject: [PATCH 41/46] [CI] Faster Eigen install on Linux

---
 .github/workflows/build_wheels.yml | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 8d649c0..a11770b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -30,15 +30,10 @@ jobs:
 
           # Install Eigen and pybind11 on manylinux images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_LINUX: >
-            yum install -y wget &&
-            wget https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz &&
+            curl -L https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz &&
             tar xzf eigen-5.0.1.tar.gz &&
-            cd eigen-5.0.1 &&
-            mkdir build &&
-            cd build &&
-            cmake .. &&
-            make install &&
-            cd ../..
+            cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=/usr/local -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF &&
+            cmake --install eigen-build
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From f8a0f5f188043a3a5a7b08b5bf2f6e1afe49a3f6 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:17:10 +0000
Subject: [PATCH 42/46] [CI] Fix curl oops

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index a11770b..5010c08 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -30,7 +30,7 @@ jobs:
 
           # Install Eigen and pybind11 on manylinux images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_LINUX: >
-            curl -L https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz &&
+            curl -L https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz -o eigen-5.0.1.tar.gz &&
             tar xzf eigen-5.0.1.tar.gz &&
             cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=/usr/local -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF &&
             cmake --install eigen-build

From 76c0ed43b14d8a8372b3c9504bcc821f472f5487 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:20:58 +0000
Subject: [PATCH 43/46] [CI] Fix stupid Cmake

---
 .github/workflows/build_wheels.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 5010c08..60b654a 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -33,7 +33,8 @@ jobs:
             curl -L https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz -o eigen-5.0.1.tar.gz &&
             tar xzf eigen-5.0.1.tar.gz &&
             cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=/usr/local -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF &&
-            cmake --install eigen-build
+            cmake --install eigen-build &&
+            ln -sf /usr/local/include/eigen3/Eigen /usr/local/include/Eigen
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From 6ed9db89b90c116adc90ef6321dc3f4baa1e5cc9 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:24:17 +0000
Subject: [PATCH 44/46] [CI] This is nicer

---
 .github/workflows/build_wheels.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 60b654a..42f41dd 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -33,8 +33,8 @@ jobs:
             curl -L https://gitlab.com/libeigen/eigen/-/archive/5.0.1/eigen-5.0.1.tar.gz -o eigen-5.0.1.tar.gz &&
             tar xzf eigen-5.0.1.tar.gz &&
             cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=/usr/local -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF &&
-            cmake --install eigen-build &&
-            ln -sf /usr/local/include/eigen3/Eigen /usr/local/include/Eigen
+            cmake --install eigen-build
+          CIBW_ENVIRONMENT_LINUX: 'CMAKE_ARGS="-DCMAKE_PREFIX_PATH=/usr/local -DCMAKE_INCLUDE_PATH=/usr/local/include/eigen3"'
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From 7feeef209d37c9d19d3b998371e13ccbf54bab36 Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:28:09 +0000
Subject: [PATCH 45/46] [CI] Even nicer

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 42f41dd..0c7684b 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -34,7 +34,7 @@ jobs:
             tar xzf eigen-5.0.1.tar.gz &&
             cmake -S eigen-5.0.1 -B eigen-build -DCMAKE_INSTALL_PREFIX=/usr/local -DEIGEN_BUILD_BLAS=OFF -DEIGEN_BUILD_LAPACK=OFF -DBUILD_TESTING=OFF &&
             cmake --install eigen-build
-          CIBW_ENVIRONMENT_LINUX: 'CMAKE_ARGS="-DCMAKE_PREFIX_PATH=/usr/local -DCMAKE_INCLUDE_PATH=/usr/local/include/eigen3"'
+          CIBW_ENVIRONMENT_LINUX: 'CPATH="/usr/local/include/eigen3"'
           CIBW_BEFORE_BUILD_LINUX: pip install pybind11[global]
 
           # Install Eigen and pybind11 on macOS

From 0af2d8a1101aac78326d3c3a880e4f653a89494e Mon Sep 17 00:00:00 2001
From: Jaroslav Fowkes <jaroslav.fowkes@stfc.ac.uk>
Date: Mon, 21 Sep 2026 16:33:02 +0000
Subject: [PATCH 46/46] [CI] Syntax tweak

---
 .github/workflows/build_wheels.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 0c7684b..cfa13fa 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -39,7 +39,7 @@ jobs:
 
           # Install Eigen and pybind11 on macOS
           CIBW_BEFORE_ALL_MACOS: brew install eigen pybind11
-          CIBW_ENVIRONMENT_MACOS: "CPLUS_INCLUDE_PATH='/opt/homebrew/include/eigen3:/usr/local/include/eigen3'"
+          CIBW_ENVIRONMENT_MACOS: 'CPLUS_INCLUDE_PATH="/opt/homebrew/include/eigen3:/usr/local/include/eigen3"'
 
           # Install Eigen and pybind11 on Windows images (no brew, need Eigen >= 3.4)
           CIBW_BEFORE_ALL_WINDOWS: "choco install eigen -y"