Create ghost_variables_tag_list alias for each system's GhostData

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: michaeldmurphy1

src/Evolution/Systems/Burgers/Subcell/GhostData.hpp

@@ -26,6 +26,7 @@ namespace Burgers::subcell {
  */
 class GhostVariables {
  public:
+  using ghost_variables_tag_list = tmpl::list<Burgers::Tags::U>;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<tmpl::list<Burgers::Tags::U>>>;

src/Evolution/Systems/Ccz4/FiniteDifference/GhostData.hpp

@@ -22,6 +22,7 @@ namespace Ccz4::fd {
  */
 class GhostVariables {
  public:
+  using ghost_variables_tag_list = Ccz4::fd::System::variables_tag_list;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<Ccz4::fd::System::variables_tag_list>>;

src/Evolution/Systems/ForceFree/Subcell/GhostData.hpp

@@ -35,6 +35,9 @@ class GhostVariables {
                  ForceFree::Tags::TildeQ>;
 
  public:
+  // TildeJ is prepended to evolved_vars in the packed DataVector (see .cpp)
+  using ghost_variables_tag_list =
+      tmpl::push_front<evolved_vars, ForceFree::Tags::TildeJ>;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<evolved_vars>, ForceFree::Tags::TildeJ>;

src/Evolution/Systems/GrMhd/GhValenciaDivClean/Subcell/PrimitiveGhostData.cpp

@@ -19,9 +19,10 @@ DataVector PrimitiveGhostVariables::apply(
     const size_t rdmp_size) {
   DataVector buffer{
       prims.number_of_grid_points() *
-          Variables<tags_for_reconstruction>::number_of_independent_components +
+          Variables<
+              ghost_variables_tag_list>::number_of_independent_components +
       rdmp_size};
-  Variables<tags_for_reconstruction> vars_to_reconstruct(
+  Variables<ghost_variables_tag_list> vars_to_reconstruct(
       buffer.data(), buffer.size() - rdmp_size);
   get<hydro::Tags::RestMassDensity<DataVector>>(vars_to_reconstruct) =
       get<hydro::Tags::RestMassDensity<DataVector>>(prims);

src/Evolution/Systems/GrMhd/GhValenciaDivClean/Subcell/PrimitiveGhostData.hpp

@@ -35,11 +35,9 @@ namespace grmhd::GhValenciaDivClean::subcell {
  * \note Only called on elements using FD.
  */
 class PrimitiveGhostVariables {
- private:
-  using tags_for_reconstruction = GhValenciaDivClean::Tags::
-      primitive_grmhd_and_spacetime_reconstruction_tags;
-
  public:
+  using ghost_variables_tag_list = GhValenciaDivClean::Tags::
+      primitive_grmhd_and_spacetime_reconstruction_tags;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<hydro::grmhd_tags<DataVector>>,

src/Evolution/Systems/GrMhd/ValenciaDivClean/Subcell/PrimitiveGhostData.hpp

@@ -38,6 +38,7 @@ class PrimitiveGhostVariables {
                  hydro::Tags::DivergenceCleaningField<DataVector>>;
 
  public:
+  using ghost_variables_tag_list = prims_to_reconstruct_tags;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<hydro::grmhd_tags<DataVector>>>;

src/Evolution/Systems/NewtonianEuler/Subcell/PrimitiveGhostData.hpp

@@ -41,6 +41,7 @@ class PrimitiveGhostVariables {
   using prims_to_reconstruct_tags = tmpl::list<MassDensity, Velocity, Pressure>;
 
  public:
+  using ghost_variables_tag_list = prims_to_reconstruct_tags;
   using return_tags = tmpl::list<>;
   using argument_tags = tmpl::list<::Tags::Variables<prim_tags>>;
 

src/Evolution/Systems/ScalarAdvection/Subcell/GhostData.hpp

@@ -26,6 +26,7 @@ namespace ScalarAdvection::subcell {
  */
 class GhostVariables {
  public:
+  using ghost_variables_tag_list = tmpl::list<ScalarAdvection::Tags::U>;
   using return_tags = tmpl::list<>;
   using argument_tags =
       tmpl::list<::Tags::Variables<tmpl::list<ScalarAdvection::Tags::U>>>;