boutproject · dschwoerer · Aug 13, 2026 · Jun 10, 2026 · Jun 11, 2026 · Jun 18, 2026
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -14,37 +14,44 @@ defaults:
 
 jobs:
   cmake_tests:
-    name: ${{ matrix.build_type.test_type }} tests, ${{ matrix.config.name }}
+    name: ${{ matrix.build_type.test_type }} tests, ${{ matrix.build_type.name }}
     runs-on: ${{ matrix.config.os }}
     env:
       OMP_NUM_THREADS: ${{ matrix.config.omp_num_threads }}
       PYTHONPATH: ${{ github.workspace }}/tools/pylib
       OMPI_MCA_rmaps_base_oversubscribe: yes
       MPIRUN: mpiexec -np
       LD_LIBRARY_PATH: /home/runner/local/lib:$LD_LIBRARY_PATH
-      BOUT_CONFIGURE_OPTIONS: ${{ matrix.config.configure_options }} -DHERMES_COVERAGE=${{ matrix.build_type.coverage }}
+      BOUT_CONFIGURE_OPTIONS: ${{ matrix.build_type.configure_options }} -DHERMES_COVERAGE=${{ matrix.build_type.coverage }}
       BUILD_TYPE: ${{ matrix.build_type.cmake_build_type }}
       TEST_TYPE: ${{ matrix.build_type.test_type }}
     strategy:
       fail-fast: false
       matrix:
         config:
-          - name: "CMake default options"
-            os: ubuntu-latest
-            configure_options: "-DPACKAGE_TESTS=OFF -DHERMES_ERROR_ON_WARNINGS=ON"
+          - os: ubuntu-latest
         build_type:
           - cmake_build_type: Debug
             test_type: unit
             coverage: ON
+            name: "CMake default options"
+            configure_options: "-DPACKAGE_TESTS=OFF -DHERMES_ERROR_ON_WARNINGS=ON"
           - cmake_build_type: Release
             test_type: integration
             coverage: OFF
+            name: "CMake default options"
+            configure_options: "-DPACKAGE_TESTS=OFF -DHERMES_ERROR_ON_WARNINGS=ON"
+          - cmake_build_type: Debug
+            test_type: None
+            name: "3D metrics (compile only)"
+            configure_options: "-DPACKAGE_TESTS=OFF -DHERMES_ERROR_ON_WARNINGS=ON -DBOUT_ENABLE_METRIC_3D=ON"
+            coverage: OFF
 
     steps:
       - name: Job information
         run: |
           echo Build: ${{ matrix.config.name }}, ${{ matrix.config.os }}
-          echo Configure options: ${{ matrix.config.configure_options }}
+          echo Configure options: ${{ matrix.build_type.configure_options }}
           echo Build type: ${{ matrix.build_type.cmake_build_type }}
           echo Coverage: ${{ matrix.build_type.coverage }}
           echo Tests to run: ${{ matrix.build_type.test_type }}

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -430,14 +430,6 @@ set(HERMES_SLOPE_LIMITER
 set_property(CACHE HERMES_SLOPE_LIMITER PROPERTY STRINGS ${SLOPE_LIMITERS})
 message(STATUS "Slope limiter: ${HERMES_SLOPE_LIMITER}")
 
-set(CONDUCTION_METHODS Original ProductJK Harmonic)
-set(HERMES_CONDUCTION_METHOD
-    Original
-    CACHE STRING "Parallel conduction method")
-set_property(CACHE HERMES_CONDUCTION_METHOD PROPERTY STRINGS
-                                                     ${CONDUCTION_METHODS})
-message(STATUS "Conduction method: ${HERMES_CONDUCTION_METHOD}")
-
 # Generate the build config header
 
 if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/include/hermes_build_config.hxx")

diff --git a/docs/sphinx/solver_numerics.rst b/docs/sphinx/solver_numerics.rst
@@ -230,21 +230,22 @@ The divergence of the flux, and so the rate of change of :math:`f` in cell
 Selecting slope limiter and conduction method
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Hermes-3 selects both the parallel advection slope limiter and the
-``Div_par_K_Grad_par_mod`` conduction discretisation at compile time
+Hermes-3 selects the parallel advection slope limiter at compile time
 through CMake cache options:
 
 .. code-block:: bash
 
    cmake -S . -B build \
-     -DHERMES_SLOPE_LIMITER=MC \
-     -DHERMES_CONDUCTION_METHOD=Original
+     -DHERMES_SLOPE_LIMITER=MC
 
 ``HERMES_SLOPE_LIMITER``
    Available values are ``MC``, ``VanAlbada``, ``WENO3``, ``MinMod``,
    ``Upwind``, and ``Superbee``.
 
-``HERMES_CONDUCTION_METHOD``
+
+The
+``Div_par_K_Grad_par_mod`` conduction discretisation can be choosen at run time with:
+``conduction_method``
    Selects the parallel heat conduction discretisation used in
    :cpp:func:`Div_par_K_Grad_par_mod`. Available values are:
 

diff --git a/external/BOUT-dev b/external/BOUT-dev
diff --git a/hermes-3.cxx b/hermes-3.cxx
@@ -121,9 +121,9 @@ class DecayLengthBoundary : public BoundaryOp {
 
     // Get cell radial length
     Coordinates* coord = mesh->getCoordinates();
-    Field2D dx = coord->dx;
-    Field2D g11 = coord->g11;
-    Field2D dr =
+    auto dx = coord->dx;
+    auto g11 = coord->g11;
+    Coordinates::FieldMetric dr =
         dx / sqrt(g11); // cell radial length. dr = dx/(Bpol * R) and g11 = (Bpol*R)**2
 
     // Only implemented for cell centre quantities
@@ -149,9 +149,10 @@ class DecayLengthBoundary : public BoundaryOp {
         //    (0, -1) Y lower boundary (inner lower target)
 
         // Distance between final cell centre and inner guard cell centre in normalised units
-        BoutReal distance =
-            0.5
-            * (dr(bndry->x, bndry->y) + dr(bndry->x - bndry->bx, bndry->y - bndry->by));
+
+        BoutReal distance = 0.5
+                            * (dr(bndry->x, bndry->y, zk)
+                               + dr(bndry->x - bndry->bx, bndry->y - bndry->by, zk));
 
         // Exponential decay
         f(bndry->x, bndry->y, zk) = f(bndry->x - bndry->bx, bndry->y - bndry->by, zk)
@@ -186,9 +187,6 @@ int Hermes::init(bool restarting) {
   output.write("Slope limiter: {}\n", hermes::limiter_typename);
   options["slope_limiter"] = hermes::limiter_typename;
   options["slope_limiter"].setConditionallyUsed();
-  output.write("Conduction method: {}\n", hermes::conduction_typename);
-  options["conduction_method"] = hermes::conduction_typename;
-  options["conduction_method"].setConditionallyUsed();
 
   // Choose normalisations
   Tnorm = options["Tnorm"].doc("Reference temperature [eV]").withDefault(100.);

diff --git a/include/braginskii_conduction.hxx b/include/braginskii_conduction.hxx
@@ -78,6 +78,8 @@ private:
   ///       - energy_flow_ylow  Energy flow diagnostics.
   ///
   void transform_impl(GuardedOptions& state) override;
+
+  std::string conduction_method{"orginal"};
 };
 
 namespace {

diff --git a/include/braginskii_ion_viscosity.hxx b/include/braginskii_ion_viscosity.hxx
@@ -8,7 +8,7 @@
 
 #include <bout/bout_types.hxx>
 #include <bout/options.hxx>
-#include <bout/vector2d.hxx>
+#include <bout/vectormetric.hxx>
 
 #include "component.hxx"
 
@@ -56,7 +56,7 @@ private:
   std::string viscosity_collisions_mode; ///< Collision selection, either multispecies or
                                          ///< braginskii
   Field3D nu;                            ///< Collision frequency for conduction
-  Vector2D Curlb_B;                      ///< Curvature vector Curl(b/B)
+  VectorMetric Curlb_B;                  ///< Curvature vector Curl(b/B)
   bool bounce_frequency;         ///< Modify the collision time with the bounce frequency?
   BoutReal bounce_frequency_q95; ///< Input q95 for when including bounce frequency change
   BoutReal bounce_frequency_epsilon; ///< Input inverse aspect ratio for including bounce

diff --git a/include/classical_diffusion.hxx b/include/classical_diffusion.hxx
@@ -2,6 +2,8 @@
 #ifndef CLASSICAL_DIFFUSION_H
 #define CLASSICAL_DIFFUSION_H
 
+#include <bout/coordinates.hxx>
+
 #include "component.hxx"
 
 struct ClassicalDiffusion : public NamedComponent<ClassicalDiffusion> {
@@ -12,7 +14,7 @@ struct ClassicalDiffusion : public NamedComponent<ClassicalDiffusion> {
   static constexpr auto type = "classical_diffusion";
 
 private:
-  Field2D Bsq; // Magnetic field squared
+  Coordinates::FieldMetric Bsq; // Magnetic field squared
 
   bool diagnose;     ///< Output additional diagnostics?
   Field3D Dn;        ///< Particle diffusion coefficient

diff --git a/include/component.hxx b/include/component.hxx
@@ -236,6 +236,7 @@ struct RegisterComponent : public ComponentFactory::RegisterInFactory<DerivedTyp
       : ComponentFactory::RegisterInFactory<DerivedType>(std::string(DerivedType::type)) {
   }
 };
+using RegisterUnavailableComponent = ComponentFactory::RegisterUnavailableInFactory;
 
 /// Faster non-printing getter for Options
 /// If this fails, it will throw BoutException

diff --git a/include/diamagnetic_drift.hxx b/include/diamagnetic_drift.hxx
@@ -2,6 +2,8 @@
 #ifndef DIAMAGNETIC_DRIFT_H
 #define DIAMAGNETIC_DRIFT_H
 
+#include <bout/vectormetric.hxx>
+
 #include "component.hxx"
 
 /// Calculate diamagnetic flows
@@ -12,9 +14,9 @@ struct DiamagneticDrift : public NamedComponent<DiamagneticDrift> {
   static constexpr auto type = "diamagnetic_drift";
 
 private:
-  Vector2D Curlb_B;
+  VectorMetric Curlb_B;
   bool bndry_flux;
-  Field2D diamag_form;
+  Coordinates::FieldMetric diamag_form;
 
   /// For every species, if it has:
   ///  - temperature