diff --git a/.github/workflows/compile_dll_with_zig.yml b/.github/workflows/compile_dll_with_zig.yml
new file mode 100644
index 00000000..5bf26119
--- /dev/null
+++ b/.github/workflows/compile_dll_with_zig.yml
@@ -0,0 +1,148 @@
+name: "Compile with CMake and Zig for Windows"
+
+on:
+  workflow_dispatch:
+
+  push:
+    branches: [ "Zig"]
+
+  pull_request:
+    branches: [ "Zig" ]
+
+env:
+  CONFIGURATION: Release
+  PLATFORM: x64
+  BOOST_VERSION: '1.8.3'
+
+
+jobs:
+  build_and_upload_installer:
+    name: Try to compile on windows with CMake
+    runs-on: windows-2022
+    # outputs:
+    #   installer_file_name: ${{ steps.output_installer_file_name.outputs.name }}
+    steps:
+    - uses: actions/checkout@v4
+
+
+    # - name: Deploy Advinst
+    #   uses: caphyon/advinst-github-action@v2.0
+    #   with:
+    #     # advinst-version: '21.3'
+    #     advinst-version: '21.7.1'
+
+    #     # advinst-license: ${{ secrets.ADVINST_LICENSE_KEY }}
+    #     # " advinst-license
+    #     # Advanced Installer license ID. This parameter is optional if you are using a simple project type.
+    #     # "
+
+    - name: Install Ninja
+      run: pip install ninja
+
+    - name: Install Zig
+      uses: goto-bus-stop/setup-zig@v2
+      with:
+        version: 0.13.0
+
+
+
+    - name: Create Ninja build system from CMake
+      shell: cmd
+      #   # CMake errors if given c:\vcpkg and /scripts/buildsystems/vcpkg.cmake
+      run: |
+        set VCPKG_ROOT=c:/vcpkg
+        .\configure_for_zig.bat
+
+
+
+
+    - name: Build sDNA
+      shell: cmd
+      #   # CMake errors if given c:\vcpkg and /scripts/buildsystems/vcpkg.cmake
+      run: |
+        set VCPKG_ROOT=c:/vcpkg
+        set BUILD_DIR=build_output_cmake_zig
+        .\run_CMake_output_build_system.bat
+
+
+
+    # - name: Output the name of the .msi installer file
+    #   id: output_installer_file_name
+    #   shell: bash
+    #   run: echo "name=$(ls sDNA_setup_win_v*.msi)" >> "$GITHUB_OUTPUT"  
+
+
+
+    - name: upload_output
+      id: installer-upload-step
+      uses: actions/upload-artifact@v4
+      with:
+        name: output
+        # this file name pattern is defined in installerbits\rename_version.py
+        # outfilename = os.path.join(outputdir, "sDNA_setup_win_v%s.msi" % filename_friendly_version)
+        path: output/Release
+
+
+  # test_installer:
+
+  #   needs: build_and_upload_installer
+
+  #   strategy:
+  #     fail-fast: false
+  #     matrix:
+  #       python_version: ['2.7', '3.5', '3.6', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+
+  #   name: "Download and run sDNA installer, and run diff tests on it. "
+    
+  #   runs-on: windows-2022
+  #   # Note:  The Windows server 2022 Github runner image already includes  
+  #   # Python (currently 6 versions from 3.7 to 3.12) and a couple of 
+  #   # VC++ redistributables.  Desktop users may need to install these 
+  #   # themselves, in addition to sDNA.      
+  #   #
+  #   # https://github.com/actions/runner-images/blob/main/images/windows/Windows2022-Readme.md
+  #   #
+
+  #   env:
+  #     installer_file_name: ${{ needs.build_and_upload_installer.outputs.installer_file_name }}
+
+  #   steps:
+
+
+  #   - uses: actions/checkout@v4
+
+  #   - name: Download installer built in previous job
+  #     uses: actions/download-artifact@v4
+  #     with:
+  #       name: installer_file
+
+  #   - shell: cmd
+  #     run: dir .
+
+
+  #   - name: Allow the .msi to be executed
+  #     run: Set-ItemProperty -Path ${{ env.installer_file_name }} -Name IsReadOnly -Value $false
+
+
+  #   - name: Run sDNA installer using powershell script. 
+  #     # This is based on @Simran-B's powershell script (from Github Community forum),
+  #     # according to GuiFalourd on Stack Overflow
+  #     # https://stackoverflow.com/a/72291019/20785734
+  #     run: |
+  #       $file = "${{ env.installer_file_name }}"
+  #       $log = "install.log" 
+  #       $procMain = Start-Process "msiexec" "/i `"$file`" /qn /l*! `"$log`"" -NoNewWindow -PassThru
+  #       $procLog = Start-Process "powershell" "Get-Content -Path `"$log`" -Wait" -NoNewWindow -PassThru 
+  #       $procMain.WaitForExit() 
+  #       $procLog.Kill()
+  #       Remove-Item $file
+
+
+  #   - name: Run regression tests
+  #     uses: ./.github/actions/run_regression_tests
+  #     with:
+  #       python_version: ${{ matrix.python_version }}
+  #       DONT_TEST_N_LINK_SUBSYSTEMS_ORDER: 1
+  #       ALLOW_NEGATIVE_FORMULA_ERROR_ON_ANY_LINK_PRESENT: 1
+  #       sdnadll: 'c:\Program Files (x86)\sDNA\x64\sdna_vs2008.dll'
+  #       sdna_debug: ""
diff --git a/.github/workflows/compile_so_with_gcc.yml b/.github/workflows/compile_so_with_gcc.yml
new file mode 100644
index 00000000..7c8bbf45
--- /dev/null
+++ b/.github/workflows/compile_so_with_gcc.yml
@@ -0,0 +1,144 @@
+name: "Compile with CMake and GCC for Ubuntu"
+
+on:
+  workflow_dispatch:
+
+  push:
+    branches: [ "GCC_Linux"]
+
+  pull_request:
+    branches: [ "GCC_Linux" ]
+
+env:
+  CONFIGURATION: Release
+  PLATFORM: x64
+  BOOST_VERSION: '1.8.3'
+
+
+jobs:
+  build_and_upload_installer:
+    name: Try to compile on Ubuntu with CMake
+    runs-on: "ubuntu-24.04"
+    # outputs:
+    #   installer_file_name: ${{ steps.output_installer_file_name.outputs.name }}
+    steps:
+    - uses: actions/checkout@v4
+
+
+    # - name: Deploy Advinst
+    #   uses: caphyon/advinst-github-action@v2.0
+    #   with:
+    #     # advinst-version: '21.3'
+    #     advinst-version: '21.7.1'
+
+    #     # advinst-license: ${{ secrets.ADVINST_LICENSE_KEY }}
+    #     # " advinst-license
+    #     # Advanced Installer license ID. This parameter is optional if you are using a simple project type.
+    #     # "
+
+
+    - name: Install Git
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y git
+
+    - uses: lukka/get-cmake@latest
+
+
+    # Install vcpkg?
+
+    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
+    - name: Create Ninja build system from CMake
+      run: |
+        VCPKG_ROOT=$VCPKG_INSTALLATION_ROOT
+        cmake -G Ninja -B build_output_cmake_gcc -S .
+
+
+
+
+    - name: Build sDNA
+      run: |
+        cmake --build build_output_cmake_gcc
+
+
+    # - name: Output the name of the .msi installer file
+    #   id: output_installer_file_name
+    #   shell: bash
+    #   run: echo "name=$(ls sDNA_setup_win_v*.msi)" >> "$GITHUB_OUTPUT"  
+
+    # - name: assemble_output
+
+
+    - name: upload_output
+      id: installer-upload-step
+      uses: actions/upload-artifact@v4
+      with:
+        name: output
+        # this file name pattern is defined in installerbits\rename_version.py
+        # outfilename = os.path.join(outputdir, "sDNA_setup_win_v%s.msi" % filename_friendly_version)
+        path: output
+
+
+  # test_installer:
+
+  #   needs: build_and_upload_installer
+
+  #   strategy:
+  #     fail-fast: false
+  #     matrix:
+  #       python_version: ['2.7', '3.5', '3.6', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+
+  #   name: "Download and run sDNA installer, and run diff tests on it. "
+    
+  #   runs-on: windows-2022
+  #   # Note:  The Windows server 2022 Github runner image already includes  
+  #   # Python (currently 6 versions from 3.7 to 3.12) and a couple of 
+  #   # VC++ redistributables.  Desktop users may need to install these 
+  #   # themselves, in addition to sDNA.      
+  #   #
+  #   # https://github.com/actions/runner-images/blob/main/images/windows/Windows2022-Readme.md
+  #   #
+
+  #   env:
+  #     installer_file_name: ${{ needs.build_and_upload_installer.outputs.installer_file_name }}
+
+  #   steps:
+
+
+  #   - uses: actions/checkout@v4
+
+  #   - name: Download installer built in previous job
+  #     uses: actions/download-artifact@v4
+  #     with:
+  #       name: installer_file
+
+  #   - shell: cmd
+  #     run: dir .
+
+
+  #   - name: Allow the .msi to be executed
+  #     run: Set-ItemProperty -Path ${{ env.installer_file_name }} -Name IsReadOnly -Value $false
+
+
+  #   - name: Run sDNA installer using powershell script. 
+  #     # This is based on @Simran-B's powershell script (from Github Community forum),
+  #     # according to GuiFalourd on Stack Overflow
+  #     # https://stackoverflow.com/a/72291019/20785734
+  #     run: |
+  #       $file = "${{ env.installer_file_name }}"
+  #       $log = "install.log" 
+  #       $procMain = Start-Process "msiexec" "/i `"$file`" /qn /l*! `"$log`"" -NoNewWindow -PassThru
+  #       $procLog = Start-Process "powershell" "Get-Content -Path `"$log`" -Wait" -NoNewWindow -PassThru 
+  #       $procMain.WaitForExit() 
+  #       $procLog.Kill()
+  #       Remove-Item $file
+
+
+  #   - name: Run regression tests
+  #     uses: ./.github/actions/run_regression_tests
+  #     with:
+  #       python_version: ${{ matrix.python_version }}
+  #       DONT_TEST_N_LINK_SUBSYSTEMS_ORDER: 1
+  #       ALLOW_NEGATIVE_FORMULA_ERROR_ON_ANY_LINK_PRESENT: 1
+  #       sdnadll: 'c:\Program Files (x86)\sDNA\x64\sdna_vs2008.dll'
+  #       sdna_debug: ""
diff --git a/.github/workflows/compile_so_with_zig.yml b/.github/workflows/compile_so_with_zig.yml
new file mode 100644
index 00000000..7cf82d91
--- /dev/null
+++ b/.github/workflows/compile_so_with_zig.yml
@@ -0,0 +1,143 @@
+name: "Compile with CMake and Zig for Ubuntu"
+
+on:
+  workflow_dispatch:
+
+  push:
+    branches: [ "Compile_with_Zig_('Clang')", "Zig_Linux"]
+
+  pull_request:
+    branches: [ "Compile_with_Zig_('Clang')", "Zig_Linux" ]
+
+env:
+  CONFIGURATION: Release
+  PLATFORM: x64
+  BOOST_VERSION: '1.8.3'
+
+
+jobs:
+  build_and_upload_installer:
+    name: Try to compile on Ubuntu with CMake
+    runs-on: "ubuntu-24.04""
+    # outputs:
+    #   installer_file_name: ${{ steps.output_installer_file_name.outputs.name }}
+    steps:
+    - uses: actions/checkout@v4
+
+
+    # - name: Deploy Advinst
+    #   uses: caphyon/advinst-github-action@v2.0
+    #   with:
+    #     # advinst-version: '21.3'
+    #     advinst-version: '21.7.1'
+
+    #     # advinst-license: ${{ secrets.ADVINST_LICENSE_KEY }}
+    #     # " advinst-license
+    #     # Advanced Installer license ID. This parameter is optional if you are using a simple project type.
+    #     # "
+
+    - name: Install Ninja
+      run: pip install ninja
+
+    - name: Install Zig
+      uses: goto-bus-stop/setup-zig@v2
+      with:
+        version: 0.13.0
+
+    # Install vcpkg?
+
+    # https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2404-Readme.md
+    - name: Create Ninja build system from CMake
+      run: |
+        VCPKG_ROOT=$VCPKG_INSTALLATION_ROOT
+        cmake -G Ninja -B build_output_cmake_zig -S .
+
+
+
+
+    - name: Build sDNA
+      run: |
+        cmake --build build_output_cmake_zig
+
+
+    # - name: Output the name of the .msi installer file
+    #   id: output_installer_file_name
+    #   shell: bash
+    #   run: echo "name=$(ls sDNA_setup_win_v*.msi)" >> "$GITHUB_OUTPUT"  
+
+    # - name: assemble_output
+
+
+    - name: upload_output
+      id: installer-upload-step
+      uses: actions/upload-artifact@v4
+      with:
+        name: output
+        # this file name pattern is defined in installerbits\rename_version.py
+        # outfilename = os.path.join(outputdir, "sDNA_setup_win_v%s.msi" % filename_friendly_version)
+        path: output
+
+
+  # test_installer:
+
+  #   needs: build_and_upload_installer
+
+  #   strategy:
+  #     fail-fast: false
+  #     matrix:
+  #       python_version: ['2.7', '3.5', '3.6', '3.7', '3.8', '3.9', '3.10', '3.11', '3.12']
+
+  #   name: "Download and run sDNA installer, and run diff tests on it. "
+    
+  #   runs-on: windows-2022
+  #   # Note:  The Windows server 2022 Github runner image already includes  
+  #   # Python (currently 6 versions from 3.7 to 3.12) and a couple of 
+  #   # VC++ redistributables.  Desktop users may need to install these 
+  #   # themselves, in addition to sDNA.      
+  #   #
+  #   # https://github.com/actions/runner-images/blob/main/images/windows/Windows2022-Readme.md
+  #   #
+
+  #   env:
+  #     installer_file_name: ${{ needs.build_and_upload_installer.outputs.installer_file_name }}
+
+  #   steps:
+
+
+  #   - uses: actions/checkout@v4
+
+  #   - name: Download installer built in previous job
+  #     uses: actions/download-artifact@v4
+  #     with:
+  #       name: installer_file
+
+  #   - shell: cmd
+  #     run: dir .
+
+
+  #   - name: Allow the .msi to be executed
+  #     run: Set-ItemProperty -Path ${{ env.installer_file_name }} -Name IsReadOnly -Value $false
+
+
+  #   - name: Run sDNA installer using powershell script. 
+  #     # This is based on @Simran-B's powershell script (from Github Community forum),
+  #     # according to GuiFalourd on Stack Overflow
+  #     # https://stackoverflow.com/a/72291019/20785734
+  #     run: |
+  #       $file = "${{ env.installer_file_name }}"
+  #       $log = "install.log" 
+  #       $procMain = Start-Process "msiexec" "/i `"$file`" /qn /l*! `"$log`"" -NoNewWindow -PassThru
+  #       $procLog = Start-Process "powershell" "Get-Content -Path `"$log`" -Wait" -NoNewWindow -PassThru 
+  #       $procMain.WaitForExit() 
+  #       $procLog.Kill()
+  #       Remove-Item $file
+
+
+  #   - name: Run regression tests
+  #     uses: ./.github/actions/run_regression_tests
+  #     with:
+  #       python_version: ${{ matrix.python_version }}
+  #       DONT_TEST_N_LINK_SUBSYSTEMS_ORDER: 1
+  #       ALLOW_NEGATIVE_FORMULA_ERROR_ON_ANY_LINK_PRESENT: 1
+  #       sdnadll: 'c:\Program Files (x86)\sDNA\x64\sdna_vs2008.dll'
+  #       sdna_debug: ""
diff --git a/sDNA/sdna_vs2008/tests/pytest/test_gathering_windows_command_line_tests.py b/sDNA/sdna_vs2008/tests/pytest/test_gathering_windows_command_line_tests.py
index 58975b0c..b944476a 100644
--- a/sDNA/sdna_vs2008/tests/pytest/test_gathering_windows_command_line_tests.py
+++ b/sDNA/sdna_vs2008/tests/pytest/test_gathering_windows_command_line_tests.py
@@ -5,6 +5,8 @@
 import sys
 import glob
 import re
+import math
+import itertools
 import subprocess
 import collections
 import tempfile
@@ -501,6 +503,54 @@ def _run(self):
         with open(self.input_file, 'rt') as f:
             return f.read()
 
+NUM_PATTERN = r'([+-]?\d+(\.\d*)?([eE][+-]?\d+)?)'
+
+def almost_equal(a, b, abs_tol = 2e-15):
+    # Whereas "0.000001E-17" != "0.0"
+    # almost_equal("0.000001E-17", "0.0") is True
+
+    last_a = 0
+    last_b = 0
+
+    matches_a = re.finditer(NUM_PATTERN, a)
+    matches_b = re.finditer(NUM_PATTERN, b)
+
+    while True:
+
+        match_a = next(matches_a, None)
+        match_b = next(matches_b, None)
+
+        if match_a is None and match_b is None:
+            return a[last_a:] == b[last_b:]
+
+        if not (match_a and match_b):
+            print('match_a: %s, match_b: %s' % (match_a, match_b))
+            return False
+
+        
+        start_a = match_a.start(0)
+        start_b = match_b.start(0)
+
+        if a[last_a:start_a] != b[last_b:start_b]:
+            
+            print('a[last_a:start_a]: %s,  b[last_b:start_b]: %s' 
+                 % (a[last_a:start_a],  b[last_b:start_b]))
+            return False
+
+        
+        last_a = match_a.end(0)
+        last_b = match_b.end(0)
+
+        if abs(float(match_a.group(0)) - float(match_b.group(0))) > abs_tol:
+            print('float(match_a.group(0)): %s, float(match_b.group(0)): %s' 
+                 % (float(match_a.group(0)), float(match_b.group(0))))
+            return False
+
+        
+
+
+
+
 
 class DiffCommand(ReadsTextInputFile):
 
@@ -648,7 +698,7 @@ def tuples_of_nontrivial_nonProgress_strings(*iterables):
                     if actual.startswith('Progress:') and actual.endswith('-bit mode'):
                         actual = ''.join(actual.partition('sDNA is running in ')[1:])
 
-                assert actual == expected, 'Error on line num i: %s.  This line (and up to the %s previous ones):\nExpected: %s, \n\n Actual: %s' % (i+1, buffer_size - 1,'\n'.join(expected_buffer), '\n'.join(actual_buffer))
+                assert almost_equal(actual, expected), 'Error on line num i: %s.  This line (and up to the %s previous ones):\nExpected: %s, \n\n Actual: %s' % (i+1, buffer_size - 1,'\n'.join(expected_buffer), '\n'.join(actual_buffer))
                 # assert actual == expected, 'i: %s, Expected: "%s", Actual: "%s"' % (i, expected, actual)
                 prev_expected = expected
                 m += 1