perf(allocations): reduced overall allocations by 95%, increaseed jacobian applicatin by 2x

This commit uses global pre allocated work space to dramatically reduce memory usage and allocation time

libmeanfield/interface/operators/prepared_mass_normalization.cppm

@@ -3,6 +3,7 @@ module;
 #include <compare>
 #include <cstdint>
 #include <expected>
+#include <memory>
 #include <mfem.hpp>
 #include <optional>
 #include <vector>
@@ -11,6 +12,7 @@ export module mean_field:operators.prepared_mass_normalization;
 
 export import :fem;
 export import :mapping.domain_mapper;
+export import :mapping.prepared_cache;
 export import :model.compiled_fixed_mass;
 export import :operators.context.gravity_field;
 export import :operators.prepared_constraint;
@@ -187,14 +189,13 @@ export namespace mean_field::operators {
         [[nodiscard]] const context::gravity_field::GravityFieldLinearizationContext &
         GetGravityContext() const noexcept;
 
-    private:
-        struct QuadraturePointData final {
-            mfem::IntegrationPoint integrationPoint;
-            mfem::Vector densityShape;
-            mapping::VolumeMappingContext mappingContext;
-            double density{0.0};
-        };
+        template <typename Visitor> void VisitMappedGeometryRules(Visitor &&visitor) const {
+            for (const ElementPAData &data : m_elements) {
+                visitor(data.elementId, *data.integrationRule);
+            }
+        }
 
+    private:
         struct ElementPAData final {
             int elementId{-1};
 
@@ -206,10 +207,15 @@ export namespace mean_field::operators {
             mfem::DofTransformation *displacementDofTransformation{nullptr};
             mfem::DofTransformation *compactificationDofTransformation{nullptr};
 
+            const mfem::IntegrationRule *integrationRule{nullptr};
+
             mfem::Vector baseDisplacement;
             mfem::Vector compactification;
 
-            std::vector<QuadraturePointData> quadraturePoints;
+            std::shared_ptr<const fem::ScalarReferenceTable> densityBasis;
+            mapping::VolumeMappingCache mappingContexts;
+            mfem::Vector density;
+            mfem::Vector quadratureWeights;
         };
 
         void BuildStaticPlan();