From c9094855da0a0d8a4c746df4fd280364cc6c2469 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:26:55 +0100
Subject: [PATCH 01/50] Add a test with MUMPS

---
 .github/actions/build/action.yml | 24 ++++++++++++++++++++++--
 .github/actions/test/action.yml  |  5 +++++
 .github/workflows/main.yml       | 11 +++++++++++
 3 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 9a48049b..012d45c0 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -1,4 +1,11 @@
 name: "Linux Build"
+
+inputs:
+  use_mumps:
+    description: 'Indicates if GMGPolar should be built with mumps support'
+    type: bool
+    required: true
+
 runs:
   using: "composite"
   steps:
@@ -7,18 +14,31 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
+    - name: Install MUMPS
+      shell: bash
+      if: inputs.use_mumps == 'true'
+      run:
+        spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Build
-      shell: 
+      shell: bash
       # ensure that the installed compiler version is used
       run: |
         mkdir build && cd build
-        cmake -DCMAKE_BUILD_TYPE=Debug -DGMGPOLAR_ENABLE_COVERAGE=ON ..
+        cmake -DCMAKE_BUILD_TYPE=Debug -DGMGPOLAR_ENABLE_COVERAGE=ON -DGMGPOLAR_USE_MUMPS=${{ inputs.use_mumps }} ..
         make -j4
     - name: create build dir archive
       shell: bash
       run: |
         tar -czf build.tar.gz build
     - name: Upload build dir archive
+      if: inputs.use_mumps == 'true'
+      uses: actions/upload-artifact@v4
+      with:
+        name: build-cpp-linux-gmgpolar-mumps
+        path: build.tar.gz
+        retention-days: 1
+    - name: Upload build dir archive
+      if: inputs.use_mumps != 'true'
       uses: actions/upload-artifact@v4
       with:
         name: build-cpp-linux-gmgpolar
diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index d25e4d06..83ec2533 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -13,6 +13,11 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
+    - name: Install MUMPS
+      shell: bash
+      if: inputs.use_mumps == 'true'
+      run:
+        spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Download build test directory
       uses: actions/download-artifact@v4
       with:
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 65529cdc..6a5ef9ae 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -13,6 +13,9 @@ jobs:
   install-and-build:
     if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        USE_MUMPS: [0, 1]
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root
@@ -23,14 +26,22 @@ jobs:
   run-unit-test:
     needs: install-and-build
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        USE_MUMPS: [0, 1]
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
+        if: USE_MUMPS == 0
         with:
           build-artifact: build-cpp-linux-gmgpolar
+      - uses: ./.github/actions/test
+        if: USE_MUMPS == 1
+        with:
+          build-artifact: build-cpp-linux-gmgpolar-mumps
 
   codecov:
     if: github.event.pull_request.draft == false

From 9de4b5efda1f9644a15f3a87e49bbe979348b798 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:28:42 +0100
Subject: [PATCH 02/50] Correct matrix usage

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 6a5ef9ae..c1b2690e 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -22,6 +22,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/build
+        with:
+          use_mumps: matrix.USE_MUMPS
       
   run-unit-test:
     needs: install-and-build
@@ -35,11 +37,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
-        if: USE_MUMPS == 0
+        if: matrix.USE_MUMPS == 0
         with:
           build-artifact: build-cpp-linux-gmgpolar
       - uses: ./.github/actions/test
-        if: USE_MUMPS == 1
+        if: matrix.USE_MUMPS == 1
         with:
           build-artifact: build-cpp-linux-gmgpolar-mumps
 

From 198e00b787e936c166d0b0de6cceefc206ca1576 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:29:16 +0100
Subject: [PATCH 03/50] Run on draft to test

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index c1b2690e..d6d2e795 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ on :
 
 jobs:
   install-and-build:
-    if: github.event.pull_request.draft == false
+    #if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       matrix:

From f8fe2f8f57d47d4d8bc9a09a007dcacfe19b7f51 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:30:11 +0100
Subject: [PATCH 04/50] Better name

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d6d2e795..a7496d4a 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -16,6 +16,7 @@ jobs:
     strategy:
       matrix:
         USE_MUMPS: [0, 1]
+    name: 'install-and-build (USE_MUMPS=${{matrix.USE_MUMPS}})'
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root

From 626c9d0f01837febb8843b45ce039d48d8e58a7d Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:30:57 +0100
Subject: [PATCH 05/50] Correct input

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a7496d4a..ce6f6a38 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -24,7 +24,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/build
         with:
-          use_mumps: matrix.USE_MUMPS
+          use_mumps: ${{ matrix.USE_MUMPS }}
       
   run-unit-test:
     needs: install-and-build

From 875250018459faf7d13219c0859979130bf9d575 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:31:32 +0100
Subject: [PATCH 06/50] Check val

---
 .github/actions/build/action.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 012d45c0..3394b5ea 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -14,6 +14,8 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
+        echo "${{ inputs.use_mumps }}"
+        echo "${{ inputs.use_mumps == 'true'}}"
     - name: Install MUMPS
       shell: bash
       if: inputs.use_mumps == 'true'

From 155098c4f428bc3f908d8b5caf09188e2b435cbd Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:32:18 +0100
Subject: [PATCH 07/50] Use bool

---
 .github/workflows/main.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ce6f6a38..ec68537f 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        USE_MUMPS: [0, 1]
+        USE_MUMPS: [false, true]
     name: 'install-and-build (USE_MUMPS=${{matrix.USE_MUMPS}})'
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
@@ -31,18 +31,18 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        USE_MUMPS: [0, 1]
+        USE_MUMPS: [false, true]
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS == 0
+        if: matrix.USE_MUMPS
         with:
           build-artifact: build-cpp-linux-gmgpolar
       - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS == 1
+        if: matrix.USE_MUMPS
         with:
           build-artifact: build-cpp-linux-gmgpolar-mumps
 

From b27be112f27f9b4f39903311b7c12cc2965a4f70 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 11:34:43 +0100
Subject: [PATCH 08/50] Clone spack

---
 .github/actions/build/action.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 3394b5ea..65de9c03 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -20,6 +20,8 @@ runs:
       shell: bash
       if: inputs.use_mumps == 'true'
       run:
+        git clone https://github.com/spack/spack.git
+        source spack/share/spack/setup-env.sh
         spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Build
       shell: bash

From 2df8bbf86689c8a4ae46a21f080ed44dbd639ecd Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 12:16:23 +0100
Subject: [PATCH 09/50] Multi-line run

---
 .github/actions/build/action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 65de9c03..a2edcb0d 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -19,7 +19,7 @@ runs:
     - name: Install MUMPS
       shell: bash
       if: inputs.use_mumps == 'true'
-      run:
+      run: |
         git clone https://github.com/spack/spack.git
         source spack/share/spack/setup-env.sh
         spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared

From 5f73c7b57acef74a63fb5c62b909af6a92ed95da Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 13:19:21 +0100
Subject: [PATCH 10/50] Different names for artifacts

---
 .github/actions/test/action.yml | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 83ec2533..68c31d85 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -49,6 +49,7 @@ runs:
         retention-days: 3
     - name: Upload coverage reports
       uses: actions/upload-artifact@v4
+      if: inputs.use_mumps != 'true'
       with:
         name: test-coverage-reports
         path: |
@@ -56,3 +57,13 @@ runs:
           build/coverage
         if-no-files-found: error
         retention-days: 1
+    - name: Upload coverage reports
+      uses: actions/upload-artifact@v4
+      if: inputs.use_mumps == 'true'
+      with:
+        name: test-coverage-reports-mumps
+        path: |
+          build/coverage-filtered.info
+          build/coverage
+        if-no-files-found: error
+        retention-days: 1

From 6e37ce379eb1cd292334c6ad73d77378c31436c0 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 13:25:02 +0100
Subject: [PATCH 11/50] Get both coverage reports

---
 .github/workflows/main.yml | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ec68537f..fe5bc2bb 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -56,9 +56,15 @@ jobs:
         uses: actions/download-artifact@v4
         with:
           name: test-coverage-reports
+          path: coverage
+      - name: Download mumps cpp coverage report
+        uses: actions/download-artifact@v4
+        with:
+          name: test-coverage-reports-mumps
+          path: coverage-mumps
       - name: Deploy to codecov.io
         uses: codecov/codecov-action@v3
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
-          files: coverage-filtered.info
+          files: coverage/coverage-filtered.info,coverage-mumps/coverage-filtered.info
           verbose: true          

From d8b16498f1348a74d65774499c53bbbe37b6a728 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:02:25 +0100
Subject: [PATCH 12/50] Install manually

---
 .github/actions/build/action.yml | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index a2edcb0d..a7e77312 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -20,9 +20,28 @@ runs:
       shell: bash
       if: inputs.use_mumps == 'true'
       run: |
-        git clone https://github.com/spack/spack.git
-        source spack/share/spack/setup-env.sh
-        spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
+        git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
+        cd METIS
+        make config prefix=$(pwd)/install
+        make install
+        ls install
+        ls install/*
+        cd ..
+        git clone https://github.com/cfwen/mumps.git
+        cd mumps
+        cp Make.inc/Makefile.inc.generic.SEQ ./Makefile.inc
+        sed -i 's/^OPTF.*/& -fopenmp/g' Makefile.inc
+        sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
+        sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
+        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/install\/lib/g' Makefile.inc
+        sed -i 's/^#IMETIS.*/IMETIS = $(topdir)\/..\/metis\/install\/include/g' Makefile.inc
+        sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
+        make s
+        make d
+        ls
+        echo $LD_LIBRARY_PATH
+        echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$(pwd)/lib"
+        #spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Build
       shell: bash
       # ensure that the installed compiler version is used

From 5e684fd0738dc510c58370138406b667b55adc91 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:11:32 +0100
Subject: [PATCH 13/50] Metis uses cmake now

---
 .github/actions/build/action.yml | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index a7e77312..ab7e7c01 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -22,10 +22,10 @@ runs:
       run: |
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
-        make config prefix=$(pwd)/install
-        make install
-        ls install
-        ls install/*
+        cmake -Bbuild
+        cmake --build build
+        ls build
+        ls build/*
         cd ..
         git clone https://github.com/cfwen/mumps.git
         cd mumps
@@ -33,8 +33,8 @@ runs:
         sed -i 's/^OPTF.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
-        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/install\/lib/g' Makefile.inc
-        sed -i 's/^#IMETIS.*/IMETIS = $(topdir)\/..\/metis\/install\/include/g' Makefile.inc
+        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/build\/lib/g' Makefile.inc
+        sed -i 's/^#IMETIS.*/IMETIS = $(topdir)\/..\/metis\/include/g' Makefile.inc
         sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
         make s
         make d

From 18acf7c7a833d51e266d10b0f928cfa72dcfda27 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:15:29 +0100
Subject: [PATCH 14/50] Specify compilers

---
 .github/actions/build/action.yml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index ab7e7c01..938ab1c4 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -36,6 +36,9 @@ runs:
         sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/build\/lib/g' Makefile.inc
         sed -i 's/^#IMETIS.*/IMETIS = $(topdir)\/..\/metis\/include/g' Makefile.inc
         sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
+        sed -i 's/^CC.*/CC = gcc/g' Makefile.inc
+        sed -i 's/^FC.*/FC = gfortran/g' Makefile.inc
+        sed -i 's/^FL.*/FL = gfortran/g' Makefile.inc
         make s
         make d
         ls

From fd5ec4337be2875ff1ec0179debbf1ebd2ade412 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:21:00 +0100
Subject: [PATCH 15/50] Missing fortran

---
 .github/actions/build/action.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 938ab1c4..d16b8cae 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -20,6 +20,7 @@ runs:
       shell: bash
       if: inputs.use_mumps == 'true'
       run: |
+        apt-get -qq -y install gfortran
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
         cmake -Bbuild

From 5820844089a5305186b9451848f7291e935e2b6d Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:25:48 +0100
Subject: [PATCH 16/50] Add flag for gfortran>=10

---
 .github/actions/build/action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index d16b8cae..c43c9a27 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -31,7 +31,7 @@ runs:
         git clone https://github.com/cfwen/mumps.git
         cd mumps
         cp Make.inc/Makefile.inc.generic.SEQ ./Makefile.inc
-        sed -i 's/^OPTF.*/& -fopenmp/g' Makefile.inc
+        sed -i 's/^OPTF.*/& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
         sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/build\/lib/g' Makefile.inc

From 4f45dc9519744e7926fdde1d05f62d93474c9198 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:34:52 +0100
Subject: [PATCH 17/50] Correct path

---
 .github/actions/build/action.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index c43c9a27..be36e709 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -34,12 +34,13 @@ runs:
         sed -i 's/^OPTF.*/& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
         sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
-        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(topdir)\/..\/metis\/build\/lib/g' Makefile.inc
-        sed -i 's/^#IMETIS.*/IMETIS = $(topdir)\/..\/metis\/include/g' Makefile.inc
+        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(pwd)\/..\/metis\/build\/lib/g' Makefile.inc
+        sed -i 's/^#IMETIS.*/IMETIS = $(pwd)\/..\/metis\/include/g' Makefile.inc
         sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
         sed -i 's/^CC.*/CC = gcc/g' Makefile.inc
         sed -i 's/^FC.*/FC = gfortran/g' Makefile.inc
         sed -i 's/^FL.*/FL = gfortran/g' Makefile.inc
+        sed -i 's/\<topdir\>/pwd/g' Makefile.inc
         make s
         make d
         ls

From 7af986c0566ced6e318e6ab0eea854a8cb8be171 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:40:17 +0100
Subject: [PATCH 18/50] Use absolute path

---
 .github/actions/build/action.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index be36e709..49c4fbd1 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -34,13 +34,13 @@ runs:
         sed -i 's/^OPTF.*/& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
         sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
         sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
-        sed -i 's/^#LMETISDIR.*/LMETISDIR = $(pwd)\/..\/metis\/build\/lib/g' Makefile.inc
-        sed -i 's/^#IMETIS.*/IMETIS = $(pwd)\/..\/metis\/include/g' Makefile.inc
+        sed -i 's/^#LMETISDIR.*/LMETISDIR = '"$(pwd)"'\/..\/metis\/build\/lib/g' Makefile.inc
+        sed -i 's/^#IMETIS.*/IMETIS = '"$(pwd)"'\/..\/metis\/include/g' Makefile.inc
         sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
         sed -i 's/^CC.*/CC = gcc/g' Makefile.inc
         sed -i 's/^FC.*/FC = gfortran/g' Makefile.inc
         sed -i 's/^FL.*/FL = gfortran/g' Makefile.inc
-        sed -i 's/\<topdir\>/pwd/g' Makefile.inc
+        sed -i 's/\$(topdir)/'"$(pwd)"'/g' Makefile.inc
         make s
         make d
         ls

From f1b672c14ce25b08c5a2ffd8a5350e68aebd6d9b Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:50:38 +0100
Subject: [PATCH 19/50] Use clearer separator

---
 .github/actions/build/action.yml | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 49c4fbd1..25803fec 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -31,16 +31,16 @@ runs:
         git clone https://github.com/cfwen/mumps.git
         cd mumps
         cp Make.inc/Makefile.inc.generic.SEQ ./Makefile.inc
-        sed -i 's/^OPTF.*/& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
-        sed -i 's/^OPTC.*/& -fopenmp/g' Makefile.inc
-        sed -i 's/^OPTL.*/& -fopenmp/g' Makefile.inc
-        sed -i 's/^#LMETISDIR.*/LMETISDIR = '"$(pwd)"'\/..\/metis\/build\/lib/g' Makefile.inc
-        sed -i 's/^#IMETIS.*/IMETIS = '"$(pwd)"'\/..\/metis\/include/g' Makefile.inc
-        sed -i 's/^ORDERINGSF.*/ORDERINGSF = -Dpord -Dmetis/g' Makefile.inc
-        sed -i 's/^CC.*/CC = gcc/g' Makefile.inc
-        sed -i 's/^FC.*/FC = gfortran/g' Makefile.inc
-        sed -i 's/^FL.*/FL = gfortran/g' Makefile.inc
-        sed -i 's/\$(topdir)/'"$(pwd)"'/g' Makefile.inc
+        sed -i 's|^OPTF.*|& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
+        sed -i 's|^OPTC.*|& -fopenmp/g' Makefile.inc
+        sed -i 's|^OPTL.*|& -fopenmp/g' Makefile.inc
+        sed -i "s|^#LMETISDIR.*|LMETISDIR = $(pwd)/../metis/build/lib|g" Makefile.inc
+        sed -i "s|^#IMETIS.*|IMETIS = $(pwd)/../metis/include|g" Makefile.inc
+        sed -i 's|^ORDERINGSF.*|ORDERINGSF = -Dpord -Dmetis|g' Makefile.inc
+        sed -i 's|^CC.*|CC = gcc|g' Makefile.inc
+        sed -i 's|^FC.*|FC = gfortran|g' Makefile.inc
+        sed -i 's|^FL.*|FL = gfortran|g' Makefile.inc
+        sed -i "s|\$(topdir)|$(pwd)/g" Makefile.inc
         make s
         make d
         ls

From c689f78c59187ceafea7632ed874a7caacf35dfd Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 15:58:45 +0100
Subject: [PATCH 20/50] Fix sed

---
 .github/actions/build/action.yml | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 25803fec..bb4293ae 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -31,16 +31,17 @@ runs:
         git clone https://github.com/cfwen/mumps.git
         cd mumps
         cp Make.inc/Makefile.inc.generic.SEQ ./Makefile.inc
-        sed -i 's|^OPTF.*|& -fopenmp -fallow-argument-mismatch/g' Makefile.inc
-        sed -i 's|^OPTC.*|& -fopenmp/g' Makefile.inc
-        sed -i 's|^OPTL.*|& -fopenmp/g' Makefile.inc
+        sed -i 's|^OPTF.*|& -fopenmp -fallow-argument-mismatch|g' Makefile.inc
+        sed -i 's|^OPTC.*|& -fopenmp|g' Makefile.inc
+        sed -i 's|^OPTL.*|& -fopenmp|g' Makefile.inc
         sed -i "s|^#LMETISDIR.*|LMETISDIR = $(pwd)/../metis/build/lib|g" Makefile.inc
         sed -i "s|^#IMETIS.*|IMETIS = $(pwd)/../metis/include|g" Makefile.inc
+        sed -i 's|^#LMETIS *= -L$(LMETISDIR) -lmetis|LMETIS = -L$(LMETISDIR) -lmetis|g' Makefile.inc
         sed -i 's|^ORDERINGSF.*|ORDERINGSF = -Dpord -Dmetis|g' Makefile.inc
         sed -i 's|^CC.*|CC = gcc|g' Makefile.inc
         sed -i 's|^FC.*|FC = gfortran|g' Makefile.inc
         sed -i 's|^FL.*|FL = gfortran|g' Makefile.inc
-        sed -i "s|\$(topdir)|$(pwd)/g" Makefile.inc
+        sed -i "s|\$(topdir)|$(pwd)|g" Makefile.inc
         make s
         make d
         ls

From c39293a40733a5dd674eabf9c6210bc0ac8ae8f4 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:03:08 +0100
Subject: [PATCH 21/50] gmake

---
 .github/actions/build/action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index bb4293ae..a5c06475 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -20,7 +20,7 @@ runs:
       shell: bash
       if: inputs.use_mumps == 'true'
       run: |
-        apt-get -qq -y install gfortran
+        apt-get -qq -y install build-essential
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
         cmake -Bbuild

From 0243e7c0a5a093cda5e0385a8b918ea3a8fa9365 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:05:43 +0100
Subject: [PATCH 22/50] Explicit topdir

---
 .github/actions/build/action.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index a5c06475..d1a73b43 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -20,7 +20,7 @@ runs:
       shell: bash
       if: inputs.use_mumps == 'true'
       run: |
-        apt-get -qq -y install build-essential
+        apt-get -qq -y install gfortran
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
         cmake -Bbuild
@@ -42,6 +42,7 @@ runs:
         sed -i 's|^FC.*|FC = gfortran|g' Makefile.inc
         sed -i 's|^FL.*|FL = gfortran|g' Makefile.inc
         sed -i "s|\$(topdir)|$(pwd)|g" Makefile.inc
+        sed -i "s|topdir = .|topdir = $(pwd)|g" Makefile
         make s
         make d
         ls

From 223ac0f6d7033b55235b9ebae6c30a9a0feaaaf5 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:09:39 +0100
Subject: [PATCH 23/50] Prepare folder

---
 .github/actions/build/action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index d1a73b43..1a2965a3 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -42,7 +42,7 @@ runs:
         sed -i 's|^FC.*|FC = gfortran|g' Makefile.inc
         sed -i 's|^FL.*|FL = gfortran|g' Makefile.inc
         sed -i "s|\$(topdir)|$(pwd)|g" Makefile.inc
-        sed -i "s|topdir = .|topdir = $(pwd)|g" Makefile
+        mkdir lib
         make s
         make d
         ls

From 53b1223f8bfdc996547e9497da3250aabc8a1d88 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:21:28 +0100
Subject: [PATCH 24/50] Fix install

---
 .github/actions/build/action.yml | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 1a2965a3..790c81b9 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -23,8 +23,9 @@ runs:
         apt-get -qq -y install gfortran
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
-        cmake -Bbuild
+        cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$(pwd)/install
         cmake --build build
+        cmake --install build
         ls build
         ls build/*
         cd ..
@@ -34,8 +35,8 @@ runs:
         sed -i 's|^OPTF.*|& -fopenmp -fallow-argument-mismatch|g' Makefile.inc
         sed -i 's|^OPTC.*|& -fopenmp|g' Makefile.inc
         sed -i 's|^OPTL.*|& -fopenmp|g' Makefile.inc
-        sed -i "s|^#LMETISDIR.*|LMETISDIR = $(pwd)/../metis/build/lib|g" Makefile.inc
-        sed -i "s|^#IMETIS.*|IMETIS = $(pwd)/../metis/include|g" Makefile.inc
+        sed -i "s|^#LMETISDIR.*|LMETISDIR = $(pwd)/../METIS/install/lib|g" Makefile.inc
+        sed -i "s|^#IMETIS.*|IMETIS = -I$(pwd)/../METIS/install/include|g" Makefile.inc
         sed -i 's|^#LMETIS *= -L$(LMETISDIR) -lmetis|LMETIS = -L$(LMETISDIR) -lmetis|g' Makefile.inc
         sed -i 's|^ORDERINGSF.*|ORDERINGSF = -Dpord -Dmetis|g' Makefile.inc
         sed -i 's|^CC.*|CC = gcc|g' Makefile.inc

From 66a8ad3bf3e6460e50fa71ff9c87deee8d0f4e61 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:32:02 +0100
Subject: [PATCH 25/50] Don't run twice

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index fe5bc2bb..66341949 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -38,7 +38,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS
+        if: ! matrix.USE_MUMPS
         with:
           build-artifact: build-cpp-linux-gmgpolar
       - uses: ./.github/actions/test

From 75dd4a8a5cf65e03abc02f977b6d50d0617e1944 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:40:12 +0100
Subject: [PATCH 26/50] Working condition?

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 66341949..90600b55 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -38,11 +38,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
-        if: ! matrix.USE_MUMPS
+        if: matrix.USE_MUMPS != true
         with:
           build-artifact: build-cpp-linux-gmgpolar
       - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS
+        if: matrix.USE_MUMPS == true
         with:
           build-artifact: build-cpp-linux-gmgpolar-mumps
 

From 4b87bd818f28f541dc27046eea180becf2414747 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 16:50:08 +0100
Subject: [PATCH 27/50] Uniform naming. Pass argument

---
 .github/actions/build/action.yml | 14 +++++++-------
 .github/actions/test/action.yml  | 10 +++++++---
 .github/workflows/main.yml       |  4 +++-
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 790c81b9..2a124801 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -1,7 +1,7 @@
 name: "Linux Build"
 
 inputs:
-  use_mumps:
+  use-mumps:
     description: 'Indicates if GMGPolar should be built with mumps support'
     type: bool
     required: true
@@ -14,11 +14,11 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
-        echo "${{ inputs.use_mumps }}"
-        echo "${{ inputs.use_mumps == 'true'}}"
+        echo "${{ inputs.use-mumps }}"
+        echo "${{ inputs.use-mumps == 'true'}}"
     - name: Install MUMPS
       shell: bash
-      if: inputs.use_mumps == 'true'
+      if: inputs.use-mumps == 'true'
       run: |
         apt-get -qq -y install gfortran
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
@@ -55,21 +55,21 @@ runs:
       # ensure that the installed compiler version is used
       run: |
         mkdir build && cd build
-        cmake -DCMAKE_BUILD_TYPE=Debug -DGMGPOLAR_ENABLE_COVERAGE=ON -DGMGPOLAR_USE_MUMPS=${{ inputs.use_mumps }} ..
+        cmake -DCMAKE_BUILD_TYPE=Debug -DGMGPOLAR_ENABLE_COVERAGE=ON -DGMGPOLAR_USE_MUMPS=${{ inputs.use-mumps }} ..
         make -j4
     - name: create build dir archive
       shell: bash
       run: |
         tar -czf build.tar.gz build
     - name: Upload build dir archive
-      if: inputs.use_mumps == 'true'
+      if: inputs.use-mumps == 'true'
       uses: actions/upload-artifact@v4
       with:
         name: build-cpp-linux-gmgpolar-mumps
         path: build.tar.gz
         retention-days: 1
     - name: Upload build dir archive
-      if: inputs.use_mumps != 'true'
+      if: inputs.use-mumps != 'true'
       uses: actions/upload-artifact@v4
       with:
         name: build-cpp-linux-gmgpolar
diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 68c31d85..558a725b 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -4,6 +4,10 @@ inputs:
   build-artifact:
     description: "Name of the build artifact that contains the unit test"
     required: true
+  use-mumps:
+    description: 'Indicates if GMGPolar should be built with mumps support'
+    type: bool
+    required: true
 
 runs:
   using: "composite"
@@ -15,7 +19,7 @@ runs:
         apt-get -qq -y install lcov
     - name: Install MUMPS
       shell: bash
-      if: inputs.use_mumps == 'true'
+      if: inputs.use-mumps == 'true'
       run:
         spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Download build test directory
@@ -49,7 +53,7 @@ runs:
         retention-days: 3
     - name: Upload coverage reports
       uses: actions/upload-artifact@v4
-      if: inputs.use_mumps != 'true'
+      if: inputs.use-mumps != 'true'
       with:
         name: test-coverage-reports
         path: |
@@ -59,7 +63,7 @@ runs:
         retention-days: 1
     - name: Upload coverage reports
       uses: actions/upload-artifact@v4
-      if: inputs.use_mumps == 'true'
+      if: inputs.use-mumps == 'true'
       with:
         name: test-coverage-reports-mumps
         path: |
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 90600b55..b71c5251 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -24,7 +24,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/build
         with:
-          use_mumps: ${{ matrix.USE_MUMPS }}
+          use-mumps: ${{ matrix.USE_MUMPS }}
       
   run-unit-test:
     needs: install-and-build
@@ -41,10 +41,12 @@ jobs:
         if: matrix.USE_MUMPS != true
         with:
           build-artifact: build-cpp-linux-gmgpolar
+          use-mumps: ${{ matrix.USE_MUMPS }}
       - uses: ./.github/actions/test
         if: matrix.USE_MUMPS == true
         with:
           build-artifact: build-cpp-linux-gmgpolar-mumps
+          use-mumps: ${{ matrix.USE_MUMPS }}
 
   codecov:
     if: github.event.pull_request.draft == false

From 572d675d6df349df634e33f3ae32e69817850395 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:12:36 +0100
Subject: [PATCH 28/50] Install not required

---
 .github/actions/test/action.yml | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 558a725b..3b5e0cde 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -17,11 +17,6 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
-    - name: Install MUMPS
-      shell: bash
-      if: inputs.use-mumps == 'true'
-      run:
-        spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
     - name: Download build test directory
       uses: actions/download-artifact@v4
       with:

From 084bc5f7e905d0b7d97e6fd385d5136bed48cd87 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:24:55 +0100
Subject: [PATCH 29/50] Fix for test-report. Use ternary

---
 .github/actions/build/action.yml | 10 +---------
 .github/actions/test/action.yml  | 15 ++-------------
 2 files changed, 3 insertions(+), 22 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 2a124801..98566817 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -62,16 +62,8 @@ runs:
       run: |
         tar -czf build.tar.gz build
     - name: Upload build dir archive
-      if: inputs.use-mumps == 'true'
-      uses: actions/upload-artifact@v4
-      with:
-        name: build-cpp-linux-gmgpolar-mumps
-        path: build.tar.gz
-        retention-days: 1
-    - name: Upload build dir archive
-      if: inputs.use-mumps != 'true'
       uses: actions/upload-artifact@v4
       with:
-        name: build-cpp-linux-gmgpolar
+        name: build-cpp-linux-gmgpolar${{ inputs.use-mumps && '-mumps' || ''}}
         path: build.tar.gz
         retention-days: 1
diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 3b5e0cde..20338532 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -42,25 +42,14 @@ runs:
     - name: Upload test report
       uses: actions/upload-artifact@v4
       with:
-        name: test-report
+        name: test-report${{ inputs.use-mumps && '-mumps' || ''}}
         path: build/tests/testreport.xml
         if-no-files-found: error
         retention-days: 3
     - name: Upload coverage reports
       uses: actions/upload-artifact@v4
-      if: inputs.use-mumps != 'true'
       with:
-        name: test-coverage-reports
-        path: |
-          build/coverage-filtered.info
-          build/coverage
-        if-no-files-found: error
-        retention-days: 1
-    - name: Upload coverage reports
-      uses: actions/upload-artifact@v4
-      if: inputs.use-mumps == 'true'
-      with:
-        name: test-coverage-reports-mumps
+        name: test-coverage-reports${{ inputs.use-mumps && '-mumps' || ''}}
         path: |
           build/coverage-filtered.info
           build/coverage

From eb084be6918140a98db1eaf08b9d901e8b00a7ff Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:30:10 +0100
Subject: [PATCH 30/50] Correct condition

---
 .github/actions/build/action.yml | 2 +-
 .github/actions/test/action.yml  | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 98566817..0a2c2069 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -64,6 +64,6 @@ runs:
     - name: Upload build dir archive
       uses: actions/upload-artifact@v4
       with:
-        name: build-cpp-linux-gmgpolar${{ inputs.use-mumps && '-mumps' || ''}}
+        name: build-cpp-linux-gmgpolar${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
         path: build.tar.gz
         retention-days: 1
diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 20338532..6e01e2b8 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -42,14 +42,14 @@ runs:
     - name: Upload test report
       uses: actions/upload-artifact@v4
       with:
-        name: test-report${{ inputs.use-mumps && '-mumps' || ''}}
+        name: test-report${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
         path: build/tests/testreport.xml
         if-no-files-found: error
         retention-days: 3
     - name: Upload coverage reports
       uses: actions/upload-artifact@v4
       with:
-        name: test-coverage-reports${{ inputs.use-mumps && '-mumps' || ''}}
+        name: test-coverage-reports${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
         path: |
           build/coverage-filtered.info
           build/coverage

From 57f6ba5fe093148065c4d10a5380eb0cdf50001d Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:35:29 +0100
Subject: [PATCH 31/50] Simplify with ternary

---
 .github/workflows/main.yml | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b71c5251..f20cf84d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -38,14 +38,8 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS != true
         with:
-          build-artifact: build-cpp-linux-gmgpolar
-          use-mumps: ${{ matrix.USE_MUMPS }}
-      - uses: ./.github/actions/test
-        if: matrix.USE_MUMPS == true
-        with:
-          build-artifact: build-cpp-linux-gmgpolar-mumps
+          build-artifact: build-cpp-linux-gmgpolar${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
           use-mumps: ${{ matrix.USE_MUMPS }}
 
   codecov:

From 875ffd54031b0f03fac70dadd4fa10530a21a93e Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:37:17 +0100
Subject: [PATCH 32/50] Finished debugging

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index f20cf84d..a1325bb5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,7 +11,7 @@ on :
 
 jobs:
   install-and-build:
-    #if: github.event.pull_request.draft == false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       matrix:

From 9bce99ffbb41d2d1b3ab06085f4ac7de7b1a5309 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:42:38 +0100
Subject: [PATCH 33/50] Set environment variables

---
 .github/actions/build/action.yml | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 0a2c2069..9167858a 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -28,6 +28,7 @@ runs:
         cmake --install build
         ls build
         ls build/*
+        echo "METIS_DIR=$(pwd)/install" >> $GITHUB_ENV
         cd ..
         git clone https://github.com/cfwen/mumps.git
         cd mumps
@@ -48,8 +49,8 @@ runs:
         make d
         ls
         echo $LD_LIBRARY_PATH
-        echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$(pwd)/lib"
-        #spack install mumps@5.5.1 ~blr_mt ~complex +double +float ~incfort ~int64 +metis ~mpi +openmp ~parmetis ~ptscotch ~scotch +shared
+        echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$(pwd)/lib" >> $GITHUB_ENV
+        echo "MUMPS_DIR=$(pwd)" >> $GITHUB_ENV
     - name: Build
       shell: bash
       # ensure that the installed compiler version is used

From bf1db7c51816ee66352880bd91ee7ea5e458a34a Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:44:00 +0100
Subject: [PATCH 34/50] Add error messages if libraries not found when
 GMGPOLAR_USE_MUMPS is requested

---
 src/CMakeLists.txt | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index db892c3c..96809611 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -226,10 +226,14 @@ if(GMGPOLAR_USE_MUMPS)
             mpiseq
         )
         target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
+    else()
+        message(SEND_ERROR "MUMPS not found")
     endif()
 
     if(METIS_FOUND)
         target_link_libraries(GMGPolarLib PUBLIC metis)
+    else()
+        message(SEND_ERROR "METIS not found")
     endif()
 endif()
 

From d60982ad3510b7f03618595fa8ed165273f52913 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 17:44:31 +0100
Subject: [PATCH 35/50] Test with debug

---
 .github/workflows/main.yml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index a1325bb5..550ca03c 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,11 +11,12 @@ on :
 
 jobs:
   install-and-build:
-    if: github.event.pull_request.draft == false
+    #if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        USE_MUMPS: [false, true]
+        #USE_MUMPS: [false, true]
+        USE_MUMPS: [true]
     name: 'install-and-build (USE_MUMPS=${{matrix.USE_MUMPS}})'
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
@@ -31,7 +32,8 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        USE_MUMPS: [false, true]
+        #USE_MUMPS: [false, true]
+        USE_MUMPS: [true]
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root

From fb5ca3b0791b9b89be7ab9b63e398245dec6b0e6 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 18:00:40 +0100
Subject: [PATCH 36/50] MPI spoof is in libseq not lib

---
 src/CMakeLists.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 96809611..dd2d7254 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -201,6 +201,11 @@ if(GMGPOLAR_USE_MUMPS)
             
             target_include_directories(GMGPolarLib PUBLIC ${MUMPS_INCLUDE_DIR})
             target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
+
+            if (EXISTS "${MUMPS_DIR}/libseq")
+              target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
+            endif()
+
             set(MUMPS_FOUND TRUE)
         endif()
     endif()

From 666bcd268e1bfaeff709600639183bf4c84b745c Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 18:04:05 +0100
Subject: [PATCH 37/50] Include dir too

---
 src/CMakeLists.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index dd2d7254..0c641651 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -203,6 +203,7 @@ if(GMGPOLAR_USE_MUMPS)
             target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
 
             if (EXISTS "${MUMPS_DIR}/libseq")
+              target_include_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
               target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
             endif()
 

From 5d873c93e61a28f6310e7c72787354f8d97b75e4 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Wed, 29 Oct 2025 18:11:09 +0100
Subject: [PATCH 38/50] Check folders

---
 .github/actions/build/action.yml | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 9167858a..bf3169ff 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -48,6 +48,8 @@ runs:
         make s
         make d
         ls
+        ls lib
+        ls libseq
         echo $LD_LIBRARY_PATH
         echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$(pwd)/lib" >> $GITHUB_ENV
         echo "MUMPS_DIR=$(pwd)" >> $GITHUB_ENV

From 033a6d18f932e34d17abf410809d2984f892b23f Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 12:21:25 +0100
Subject: [PATCH 39/50] Install using CMake

---
 .github/actions/build/action.yml | 34 +++++++++-----------------------
 1 file changed, 9 insertions(+), 25 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index bf3169ff..7b6aadff 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -23,36 +23,20 @@ runs:
         apt-get -qq -y install gfortran
         git clone -b v5.1.0.4 https://github.com/scivision/METIS.git
         cd METIS
-        cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$(pwd)/install
+        cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$(pwd)/install -DCMAKE_BUILD_TYPE=Release
         cmake --build build
         cmake --install build
-        ls build
-        ls build/*
+        ls install/*
         echo "METIS_DIR=$(pwd)/install" >> $GITHUB_ENV
+        echo "METIS_ROOT=$(pwd)/install" >> $GITHUB_ENV
         cd ..
-        git clone https://github.com/cfwen/mumps.git
+        git clone -b v5.5.1.11 https://github.com/scivision/mumps.git
         cd mumps
-        cp Make.inc/Makefile.inc.generic.SEQ ./Makefile.inc
-        sed -i 's|^OPTF.*|& -fopenmp -fallow-argument-mismatch|g' Makefile.inc
-        sed -i 's|^OPTC.*|& -fopenmp|g' Makefile.inc
-        sed -i 's|^OPTL.*|& -fopenmp|g' Makefile.inc
-        sed -i "s|^#LMETISDIR.*|LMETISDIR = $(pwd)/../METIS/install/lib|g" Makefile.inc
-        sed -i "s|^#IMETIS.*|IMETIS = -I$(pwd)/../METIS/install/include|g" Makefile.inc
-        sed -i 's|^#LMETIS *= -L$(LMETISDIR) -lmetis|LMETIS = -L$(LMETISDIR) -lmetis|g' Makefile.inc
-        sed -i 's|^ORDERINGSF.*|ORDERINGSF = -Dpord -Dmetis|g' Makefile.inc
-        sed -i 's|^CC.*|CC = gcc|g' Makefile.inc
-        sed -i 's|^FC.*|FC = gfortran|g' Makefile.inc
-        sed -i 's|^FL.*|FL = gfortran|g' Makefile.inc
-        sed -i "s|\$(topdir)|$(pwd)|g" Makefile.inc
-        mkdir lib
-        make s
-        make d
-        ls
-        ls lib
-        ls libseq
-        echo $LD_LIBRARY_PATH
-        echo "LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$(pwd)/lib" >> $GITHUB_ENV
-        echo "MUMPS_DIR=$(pwd)" >> $GITHUB_ENV
+        cmake -Bbuild -DBUILD_SINGLE=on -DBUILD_DOUBLE=on -Dmetis=on -Dopenmp=on -Dparallel=off -DCMAKE_INSTALL_PREFIX=$(pwd)/install -DCMAKE_BUILD_TYPE=Release -S .
+        cmake --build build
+        cmake --install build
+        ls install/*
+        echo "MUMPS_DIR=$(pwd)/install" >> $GITHUB_ENV
     - name: Build
       shell: bash
       # ensure that the installed compiler version is used

From da172f2810d8e3596224d91710ccdbcef65d9777 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 12:25:52 +0100
Subject: [PATCH 40/50] Export so var is available locally

---
 .github/actions/build/action.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 7b6aadff..a98341a2 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -28,7 +28,7 @@ runs:
         cmake --install build
         ls install/*
         echo "METIS_DIR=$(pwd)/install" >> $GITHUB_ENV
-        echo "METIS_ROOT=$(pwd)/install" >> $GITHUB_ENV
+        export METIS_ROOT=$(pwd)/install
         cd ..
         git clone -b v5.5.1.11 https://github.com/scivision/mumps.git
         cd mumps

From 3b3793943dab96d693b3a0f477514126a5bc895f Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 13:10:38 +0100
Subject: [PATCH 41/50] Fix linking

---
 CMakeLists.txt     |  7 +++-
 src/CMakeLists.txt | 90 ++++++++++++++++++++++++----------------------
 2 files changed, 54 insertions(+), 43 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4670da20..57f1454d 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,4 @@
 cmake_minimum_required(VERSION 3.12)
-project(GMGPolar VERSION 2.0.0 LANGUAGES CXX)
 
 # Options should be defined before they're used
 option(GMGPOLAR_BUILD_TESTS "Build GMGPolar unit tests." ON)
@@ -7,6 +6,12 @@ option(GMGPOLAR_USE_LIKWID "Use LIKWID to measure code (regions)." OFF)
 option(GMGPOLAR_USE_MUMPS "Use MUMPS to solve linear systems." OFF)
 option(GMGPOLAR_ENABLE_COVERAGE "Enable code coverage reporting (requires GCC/Clang)" OFF)
 
+if (${GMGPOLAR_USE_MUMPS})
+    project(GMGPolar VERSION 2.0.0 LANGUAGES CXX Fortran)
+else()
+project(GMGPolar VERSION 2.0.0 LANGUAGES CXX)
+endif()
+
 set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 0c641651..ee7b72a5 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -192,54 +192,60 @@ endif()
 
 # Handle MUMPS configuration
 if(GMGPOLAR_USE_MUMPS)
-    if(DEFINED ENV{MUMPS_DIR})
-        set(MUMPS_DIR $ENV{MUMPS_DIR})
-        
-        if(EXISTS "${MUMPS_DIR}/include" AND EXISTS "${MUMPS_DIR}/lib")
-            set(MUMPS_INCLUDE_DIR "${MUMPS_DIR}/include")
-            set(MUMPS_LIBRARY_DIR "${MUMPS_DIR}/lib")
-            
-            target_include_directories(GMGPolarLib PUBLIC ${MUMPS_INCLUDE_DIR})
-            target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
+    find_package(MUMPS COMPONENTS OpenMP METIS)
+    if (${MUMPS_FOUND})
+      target_link_libraries(GMGPolarLib PUBLIC MUMPS::MUMPS)
+      target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
+    else()
+      if(DEFINED ENV{MUMPS_DIR})
+          set(MUMPS_DIR $ENV{MUMPS_DIR})
+          
+          if(EXISTS "${MUMPS_DIR}/include" AND EXISTS "${MUMPS_DIR}/lib")
+              set(MUMPS_INCLUDE_DIR "${MUMPS_DIR}/include")
+              set(MUMPS_LIBRARY_DIR "${MUMPS_DIR}/lib")
+              
+              target_include_directories(GMGPolarLib PUBLIC ${MUMPS_INCLUDE_DIR})
+              target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
 
-            if (EXISTS "${MUMPS_DIR}/libseq")
-              target_include_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
-              target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
-            endif()
+              if (EXISTS "${MUMPS_DIR}/libseq")
+                target_include_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
+                target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
+              endif()
 
-            set(MUMPS_FOUND TRUE)
-        endif()
-    endif()
+              set(MUMPS_FOUND TRUE)
+          endif()
+      endif()
 
-    if(DEFINED ENV{METIS_DIR})
-        set(METIS_DIR $ENV{METIS_DIR})
+      if(DEFINED ENV{METIS_DIR})
+          set(METIS_DIR $ENV{METIS_DIR})
 
-        if(EXISTS "${METIS_DIR}/include" AND EXISTS "${METIS_DIR}/lib")
-            set(METIS_INCLUDE_DIR "${METIS_DIR}/include")
-            set(METIS_LIBRARY_DIR "${METIS_DIR}/lib")
-            
-            target_include_directories(GMGPolarLib PUBLIC ${METIS_INCLUDE_DIR})
-            target_link_directories(GMGPolarLib PUBLIC ${METIS_LIBRARY_DIR})
-            set(METIS_FOUND TRUE)
-        endif()
-    endif()
+          if(EXISTS "${METIS_DIR}/include" AND EXISTS "${METIS_DIR}/lib")
+              set(METIS_INCLUDE_DIR "${METIS_DIR}/include")
+              set(METIS_LIBRARY_DIR "${METIS_DIR}/lib")
+              
+              target_include_directories(GMGPolarLib PUBLIC ${METIS_INCLUDE_DIR})
+              target_link_directories(GMGPolarLib PUBLIC ${METIS_LIBRARY_DIR})
+              set(METIS_FOUND TRUE)
+          endif()
+      endif()
 
-    if(MUMPS_FOUND)
-        target_link_libraries(GMGPolarLib PUBLIC
-            mumps_common
-            smumps
-            dmumps
-            mpiseq
-        )
-        target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
-    else()
-        message(SEND_ERROR "MUMPS not found")
-    endif()
+      if(MUMPS_FOUND)
+          target_link_libraries(GMGPolarLib PUBLIC
+              mumps_common
+              smumps
+              dmumps
+              mpiseq
+          )
+          target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
+      else()
+          message(SEND_ERROR "MUMPS not found")
+      endif()
 
-    if(METIS_FOUND)
-        target_link_libraries(GMGPolarLib PUBLIC metis)
-    else()
-        message(SEND_ERROR "METIS not found")
+      if(METIS_FOUND)
+          target_link_libraries(GMGPolarLib PUBLIC metis)
+      else()
+          message(SEND_ERROR "METIS not found")
+      endif()
     endif()
 endif()
 

From d17c370ae2b1b42602dcd580745feb5f8a85a949 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 13:17:51 +0100
Subject: [PATCH 42/50] Ensure METIS is found

---
 .github/actions/build/action.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index a98341a2..9b0da3db 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -28,6 +28,7 @@ runs:
         cmake --install build
         ls install/*
         echo "METIS_DIR=$(pwd)/install" >> $GITHUB_ENV
+        echo "METIS_ROOT=$(pwd)/install" >> $GITHUB_ENV
         export METIS_ROOT=$(pwd)/install
         cd ..
         git clone -b v5.5.1.11 https://github.com/scivision/mumps.git

From b4b38d41d0ebbb3430962cac6390bf2aa215c1dc Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:04:13 +0100
Subject: [PATCH 43/50] Correct condition

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

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 550ca03c..0bc75692 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -41,7 +41,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
         with:
-          build-artifact: build-cpp-linux-gmgpolar${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
+          build-artifact: build-cpp-linux-gmgpolar${{ matrix.USE_MUMPS == 'true' && '-mumps' || ''}}
           use-mumps: ${{ matrix.USE_MUMPS }}
 
   codecov:

From c85e5d1dd0a9ec1f1d67b46383ab43db9d3103fb Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:08:25 +0100
Subject: [PATCH 44/50] Tidy up fail

---
 src/CMakeLists.txt | 86 ++++++++++++++++++++++------------------------
 1 file changed, 42 insertions(+), 44 deletions(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ee7b72a5..3cf596c1 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -196,56 +196,54 @@ if(GMGPOLAR_USE_MUMPS)
     if (${MUMPS_FOUND})
       target_link_libraries(GMGPolarLib PUBLIC MUMPS::MUMPS)
       target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
-    else()
-      if(DEFINED ENV{MUMPS_DIR})
-          set(MUMPS_DIR $ENV{MUMPS_DIR})
-          
-          if(EXISTS "${MUMPS_DIR}/include" AND EXISTS "${MUMPS_DIR}/lib")
-              set(MUMPS_INCLUDE_DIR "${MUMPS_DIR}/include")
-              set(MUMPS_LIBRARY_DIR "${MUMPS_DIR}/lib")
-              
-              target_include_directories(GMGPolarLib PUBLIC ${MUMPS_INCLUDE_DIR})
-              target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
+    elseif(DEFINED ENV{MUMPS_DIR})
+        set(MUMPS_DIR $ENV{MUMPS_DIR})
+
+        if(EXISTS "${MUMPS_DIR}/include" AND EXISTS "${MUMPS_DIR}/lib")
+            set(MUMPS_INCLUDE_DIR "${MUMPS_DIR}/include")
+            set(MUMPS_LIBRARY_DIR "${MUMPS_DIR}/lib")
 
-              if (EXISTS "${MUMPS_DIR}/libseq")
-                target_include_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
-                target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
-              endif()
+            target_include_directories(GMGPolarLib PUBLIC ${MUMPS_INCLUDE_DIR})
+            target_link_directories(GMGPolarLib PUBLIC ${MUMPS_LIBRARY_DIR})
 
-              set(MUMPS_FOUND TRUE)
-          endif()
-      endif()
+            if (EXISTS "${MUMPS_DIR}/libseq")
+              target_include_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
+              target_link_directories(GMGPolarLib PUBLIC "${MUMPS_DIR}/libseq")
+            endif()
 
-      if(DEFINED ENV{METIS_DIR})
-          set(METIS_DIR $ENV{METIS_DIR})
+            set(MUMPS_FOUND TRUE)
+        endif()
 
-          if(EXISTS "${METIS_DIR}/include" AND EXISTS "${METIS_DIR}/lib")
-              set(METIS_INCLUDE_DIR "${METIS_DIR}/include")
-              set(METIS_LIBRARY_DIR "${METIS_DIR}/lib")
-              
-              target_include_directories(GMGPolarLib PUBLIC ${METIS_INCLUDE_DIR})
-              target_link_directories(GMGPolarLib PUBLIC ${METIS_LIBRARY_DIR})
-              set(METIS_FOUND TRUE)
-          endif()
-      endif()
+        if(MUMPS_FOUND)
+            target_link_libraries(GMGPolarLib PUBLIC
+                mumps_common
+                smumps
+                dmumps
+                mpiseq
+            )
+            target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
+        else()
+            message(SEND_ERROR "MUMPS not found")
+        endif()
+    endif()
 
-      if(MUMPS_FOUND)
-          target_link_libraries(GMGPolarLib PUBLIC
-              mumps_common
-              smumps
-              dmumps
-              mpiseq
-          )
-          target_compile_definitions(GMGPolarLib PUBLIC GMGPOLAR_USE_MUMPS)
-      else()
-          message(SEND_ERROR "MUMPS not found")
-      endif()
+    if(DEFINED ENV{METIS_DIR})
+        set(METIS_DIR $ENV{METIS_DIR})
 
-      if(METIS_FOUND)
-          target_link_libraries(GMGPolarLib PUBLIC metis)
-      else()
-          message(SEND_ERROR "METIS not found")
-      endif()
+        if(EXISTS "${METIS_DIR}/include" AND EXISTS "${METIS_DIR}/lib")
+            set(METIS_INCLUDE_DIR "${METIS_DIR}/include")
+            set(METIS_LIBRARY_DIR "${METIS_DIR}/lib")
+
+            target_include_directories(GMGPolarLib PUBLIC ${METIS_INCLUDE_DIR})
+            target_link_directories(GMGPolarLib PUBLIC ${METIS_LIBRARY_DIR})
+            set(METIS_FOUND TRUE)
+        endif()
+
+        if(METIS_FOUND)
+            target_link_libraries(GMGPolarLib PUBLIC metis)
+        else()
+            message(SEND_ERROR "METIS not found")
+        endif()
     endif()
 endif()
 

From 451218067f5abeb0f72d23f6aaa20de0bad2a075 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:09:53 +0100
Subject: [PATCH 45/50] Fix linkage

---
 CMakeLists.txt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 57f1454d..47cad7d8 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,9 +7,10 @@ option(GMGPOLAR_USE_MUMPS "Use MUMPS to solve linear systems." OFF)
 option(GMGPOLAR_ENABLE_COVERAGE "Enable code coverage reporting (requires GCC/Clang)" OFF)
 
 if (${GMGPOLAR_USE_MUMPS})
+    # MUMPS does not automatically provide Fortran libraries
     project(GMGPolar VERSION 2.0.0 LANGUAGES CXX Fortran)
 else()
-project(GMGPolar VERSION 2.0.0 LANGUAGES CXX)
+    project(GMGPolar VERSION 2.0.0 LANGUAGES CXX)
 endif()
 
 set(CMAKE_CXX_STANDARD 20)

From 1670731e42fbd83c669bc8fbaacce429f4679dd5 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:16:02 +0100
Subject: [PATCH 46/50] Try to fix artifact name

---
 .github/actions/test/action.yml | 2 +-
 .github/workflows/main.yml      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index 6e01e2b8..ef91065a 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -20,7 +20,7 @@ runs:
     - name: Download build test directory
       uses: actions/download-artifact@v4
       with:
-        name: ${{ inputs.build-artifact }}
+        name: ${{ inputs.build-artifact }}${{ inputs.use-mumps == 'true' && '-mumps' || ''}}
     - name: extract build archive
       shell: bash
       run: |
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 0bc75692..d4b5970f 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -41,7 +41,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/test
         with:
-          build-artifact: build-cpp-linux-gmgpolar${{ matrix.USE_MUMPS == 'true' && '-mumps' || ''}}
+          build-artifact: build-cpp-linux-gmgpolar
           use-mumps: ${{ matrix.USE_MUMPS }}
 
   codecov:

From 6cb1271e0d83e3b505156d4ce94b739fce194e98 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:30:38 +0100
Subject: [PATCH 47/50] Get fortran

---
 .github/actions/test/action.yml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/.github/actions/test/action.yml b/.github/actions/test/action.yml
index ef91065a..556b0020 100644
--- a/.github/actions/test/action.yml
+++ b/.github/actions/test/action.yml
@@ -17,6 +17,10 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
+    - name: Install MUMPS Dependencies
+      shell: bash
+      run: |
+        apt-get -qq -y install gfortran
     - name: Download build test directory
       uses: actions/download-artifact@v4
       with:

From fbdb20b0e4e262c11a886207891adcf2ab2f6918 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:45:34 +0100
Subject: [PATCH 48/50] Done testing

---
 .github/workflows/main.yml | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index d4b5970f..7f679fd5 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,12 +11,11 @@ on :
 
 jobs:
   install-and-build:
-    #if: github.event.pull_request.draft == false
+    if: github.event.pull_request.draft == false
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        #USE_MUMPS: [false, true]
-        USE_MUMPS: [true]
+        USE_MUMPS: [false, true]
     name: 'install-and-build (USE_MUMPS=${{matrix.USE_MUMPS}})'
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
@@ -32,8 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        #USE_MUMPS: [false, true]
-        USE_MUMPS: [true]
+        USE_MUMPS: [false, true]
     container:
       image: ghcr.io/gyselax/gyselalibxx_env:latest
       options: --user root

From 115a8a146b350c87035131a26efe160c3bc3d4d8 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:46:03 +0100
Subject: [PATCH 49/50] Remove print

---
 .github/actions/build/action.yml | 2 --
 1 file changed, 2 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index 9b0da3db..a7d5bcb8 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -14,8 +14,6 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
-        echo "${{ inputs.use-mumps }}"
-        echo "${{ inputs.use-mumps == 'true'}}"
     - name: Install MUMPS
       shell: bash
       if: inputs.use-mumps == 'true'

From a2810d68e64cdf69e067006eea98587fae6d48e8 Mon Sep 17 00:00:00 2001
From: Emily Bourne <emily.bourne@epfl.ch>
Date: Thu, 30 Oct 2025 14:46:42 +0100
Subject: [PATCH 50/50] Split for clean action

---
 .github/actions/build/action.yml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/.github/actions/build/action.yml b/.github/actions/build/action.yml
index a7d5bcb8..32147102 100644
--- a/.github/actions/build/action.yml
+++ b/.github/actions/build/action.yml
@@ -14,7 +14,7 @@ runs:
       run: |
         apt-get -qq update
         apt-get -qq -y install lcov
-    - name: Install MUMPS
+    - name: Install METIS
       shell: bash
       if: inputs.use-mumps == 'true'
       run: |
@@ -27,8 +27,10 @@ runs:
         ls install/*
         echo "METIS_DIR=$(pwd)/install" >> $GITHUB_ENV
         echo "METIS_ROOT=$(pwd)/install" >> $GITHUB_ENV
-        export METIS_ROOT=$(pwd)/install
-        cd ..
+    - name: Install MUMPS
+      shell: bash
+      if: inputs.use-mumps == 'true'
+      run: |
         git clone -b v5.5.1.11 https://github.com/scivision/mumps.git
         cd mumps
         cmake -Bbuild -DBUILD_SINGLE=on -DBUILD_DOUBLE=on -Dmetis=on -Dopenmp=on -Dparallel=off -DCMAKE_INSTALL_PREFIX=$(pwd)/install -DCMAKE_BUILD_TYPE=Release -S .