Support EQDSK field

src/pcms/field/CMakeLists.txt

@@ -43,6 +43,7 @@ if (PCMS_ENABLE_OMEGA_H)
             uniform_grid_binary_field.h
             evaluator/uniform_grid.h
             evaluator/uniform_grid_spline.h
+            eqdsk_field.h
             evaluator/mls_options.h
             evaluator/mls_interpolation.hpp
             evaluator/mls_interpolation_impl.hpp

src/pcms/field/eqdsk_field.h

@@ -0,0 +1,76 @@
+#ifndef PCMS_EQDSK_FIELD_H
+#define PCMS_EQDSK_FIELD_H
+
+#include "pcms/utility/eqdsk.h"
+#include "pcms/field/layout/uniform_grid.h"
+#include "pcms/field/function_space/spline.h"
+
+#include <string>
+
+namespace pcms
+{
+
+struct EQDSKField
+{
+  SplineFunctionSpace space;
+  Field<Real> field;
+};
+
+// TODD: @jacobmerson replace with Function.
+struct EQDSKFieldWithData
+{
+  EQDSKData data;
+  SplineFunctionSpace space;
+  Field<Real> field;
+};
+
+/**
+ * @brief Create a SplineFunctionSpace and Field from EQDSKData, combining
+ * function space creation, field allocation, and DOF holder data population
+ * into a single call.
+ *
+ * Performs three steps:
+ * 1. Creates a SplineFunctionSpace from the EQDSK data
+ * 2. Creates a Field<Real> on that function space
+ * 3. Populates the field's DOF holder with the PSIZR flux data
+ *
+ * @param eqdsk_data The EQDSK equilibrium data containing the grid and flux
+ *                   values.
+ * @return EQDSKField A struct containing the function space and populated
+ *                    field, ready for evaluation.
+ */
+inline EQDSKField MakeEQDSKField(const EQDSKData& eqdsk_data)
+{
+  auto space = SplineFunctionSpace::FromUniformGrid(
+    eqdsk_data.grid, CoordinateSystem::Cartesian);
+  auto field = space.CreateField<Real>();
+  field.GetData().SetDOFHolderData(Rank1View<const Real, DeviceMemorySpace>(
+    eqdsk_data.PSIZR.data(), eqdsk_data.PSIZR.extent(0)));
+  return {std::move(space), std::move(field)};
+}
+
+/**
+ * @brief Read an EQDSK file and construct a SplineFunctionSpace and Field from
+ * it, combining file I/O, function space creation, field allocation, and DOF
+ * holder data population into a single call.
+ *
+ * Performs four steps:
+ * 1. Reads the EQDSK file into an EQDSKData
+ * 2. Creates a SplineFunctionSpace from the data
+ * 3. Creates a Field<Real> on that function space
+ * 4. Populates the field's DOF holder with the PSIZR flux data
+ *
+ * @param filename Path to the EQDSK equilibrium file.
+ * @return EQDSKFieldWithData A struct containing the data, function space,
+ *                            and populated field, ready for evaluation.
+ */
+inline EQDSKFieldWithData MakeEQDSKField(const std::string& filename)
+{
+  auto eqdsk_data = EQDSKData(filename);
+  auto [space, field] = MakeEQDSKField(eqdsk_data);
+  return {std::move(eqdsk_data), std::move(space), std::move(field)};
+}
+
+} // namespace pcms
+
+#endif // PCMS_EQDSK_FIELD_H

src/pcms/field/function_space/spline.h

@@ -10,6 +10,7 @@
 #include "pcms/field/out_of_bounds_policy.h"
 #include "pcms/field/point_evaluator.h"
 #include "pcms/utility/arrays.h"
+#include "pcms/utility/eqdsk.h"
 #include "pcms/utility/memory_spaces.h"
 #include "pcms/utility/uniform_grid.h"
 

src/pcms/utility/CMakeLists.txt

@@ -5,6 +5,7 @@ set(
         bounding_box.h
         common.h
         entity_types.h
+        eqdsk.h
         mesh_geometry.h
         memory_spaces.h
         mpi_type.h
@@ -20,6 +21,7 @@ set(
 set(
         PCMS_UTILITY_SOURCES
         assert.cpp
+        eqdsk.cpp
         print.cpp
 )
 add_library(pcms_utility ${PCMS_UTILITY_SOURCES})
@@ -33,6 +35,9 @@ target_include_directories(
         "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/../..>"
         "$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>")
 target_link_libraries(pcms_utility PUBLIC Kokkos::kokkos perfstubs)
+if(PCMS_ENABLE_OMEGA_H)
+    target_link_libraries(pcms_utility PUBLIC Omega_h::omega_h)
+endif()
 target_compile_features(pcms_utility PUBLIC cxx_std_20)
 
 set_target_properties(