feat(libmeanfield): centrifugal + pressure

libmeanfield/interface/mapping/compactification/kelvin.cppm

@@ -0,0 +1,50 @@
+module;
+#include <mfem.hpp>
+
+export module mean_field:mapping.kelvin;
+export import :mapping.compactification;
+export import :mapping.types;
+export import :mapping.compactification.options;
+
+export namespace mean_field::mapping::compactification {
+
+    class KelvinCompactification final : public ExteriorDomainMap {
+    public:
+        explicit KelvinCompactification(
+            options::KelvinCompactificationOptions options
+        );
+
+        [[nodiscard]] MappingStatus Evaluate(
+            const ExteriorMapInput &input,
+            ExteriorMapResult &result
+        ) const override;
+
+        [[nodiscard]] MappingStatus EvaluateVariation(
+            const ExteriorMapInput &input,
+            const ExteriorMapResult &result,
+            const ExteriorMapDirection &direction,
+            ExteriorMapVariation &variation
+        ) const override;
+
+        [[nodiscard]] std::string_view GetName() const noexcept override;
+
+        [[nodiscard]] double GetReferenceStellarRadius() const noexcept;
+        [[nodiscard]] double GetReferenceInfinityRadius() const noexcept;
+        [[nodiscard]] double GetCoordinateTolerance() const noexcept;
+
+    private:
+        struct RadialFactors {
+            double coordinate;
+            double computational_radius;
+            double scale;
+            double scale_derivative;
+        };
+
+        [[nodiscard]] MappingStatus ComputeRadialFactors(
+            double compactification_coordinate,
+            RadialFactors &factors
+        ) const;
+
+        options::KelvinCompactificationOptions m_options;
+    };
+} // namespace mean_field::mapping::compactification