Enhance ROM Utilities: Introduce FindNearestNeighbors Utility for ROMs.

applications/RomApplication/custom_python/add_custom_utilities_to_python.cpp

@@ -67,6 +67,8 @@ void AddCustomUtilitiesToPython(pybind11::module& m)
         .def_static("ProjectRomSolutionIncrementToNodes", &RomAuxiliaryUtilities::ProjectRomSolutionIncrementToNodes)
         .def_static("GetElementIdsInModelPart", &RomAuxiliaryUtilities::GetElementIdsInModelPart)
         .def_static("GetConditionIdsInModelPart", &RomAuxiliaryUtilities::GetConditionIdsInModelPart)
+        .def_static("InitializeBins", &RomAuxiliaryUtilities::InitializeBins)
+        .def_static("FindNearestNeighbors", &RomAuxiliaryUtilities::FindNearestNeighbors)
         ;
 }
 

applications/RomApplication/custom_strategies/rom_builder_and_solver.h

@@ -249,7 +249,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
     SizeType GetNumberOfROMModes() const noexcept
     {
         return mNumberOfRomModes;
-    } 
+    }
 
     void ProjectToFineBasis(
         const TSystemVectorType& rRomUnkowns,
@@ -280,7 +280,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
         r_root_mp.GetValue(ROM_SOLUTION_INCREMENT) = ZeroVector(GetNumberOfROMModes());
     }
 
-    
+
     void BuildAndSolve(
         typename TSchemeType::Pointer pScheme,
         ModelPart &rModelPart,
@@ -294,6 +294,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
         RomSystemVectorType brom = ZeroVector(GetNumberOfROMModes());
 
         BuildROM(pScheme, rModelPart, Arom, brom);
+        CalculateReactions(pScheme, rModelPart, A, Dx, b);
         SolveROM(rModelPart, Arom, brom, Dx);
 
         KRATOS_CATCH("")
@@ -414,7 +415,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
     ///@}
     ///@name Protected operators
     ///@{
-    
+
     void BuildRHSNoDirichlet(
         ModelPart& rModelPart,
         TSystemVectorType& rb)
@@ -453,7 +454,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
                     AtomicAdd(r_bi, r_rhs_cond[i]); // Building RHS.
                 }
             });
-        }   
+        }
 
         KRATOS_CATCH("")
 
@@ -536,7 +537,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
 
         KRATOS_CATCH("")
     }
-    
+
     static DofQueue ExtractDofSet(
         typename TSchemeType::Pointer pScheme,
         ModelPart& rModelPart)
@@ -626,7 +627,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
         RomSystemMatrixType aux = {};    // Auxiliary: romA = phi.t * (LHS * phi) := phi.t * aux
     };
 
-    
+
     /**
      * Class to sum-reduce matrices and vectors.
      */
@@ -681,7 +682,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
     }
 
     /**
-     * Builds the reduced system of equations on rank 0 
+     * Builds the reduced system of equations on rank 0
      */
     virtual void BuildROM(
         typename TSchemeType::Pointer pScheme,
@@ -712,7 +713,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
         if(!elements.empty())
         {
             std::tie(rA, rb) =
-            block_for_each<SystemSumReducer>(elements, assembly_tls_container, 
+            block_for_each<SystemSumReducer>(elements, assembly_tls_container,
                 [&](Element& r_element, AssemblyTLS& r_thread_prealloc)
             {
                 return CalculateLocalContribution(r_element, r_thread_prealloc, *pScheme, r_current_process_info);
@@ -726,7 +727,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
             RomSystemVectorType bconditions;
 
             std::tie(Aconditions, bconditions) =
-            block_for_each<SystemSumReducer>(conditions, assembly_tls_container, 
+            block_for_each<SystemSumReducer>(conditions, assembly_tls_container,
                 [&](Condition& r_condition, AssemblyTLS& r_thread_prealloc)
             {
                 return CalculateLocalContribution(r_condition, r_thread_prealloc, *pScheme, r_current_process_info);
@@ -754,7 +755,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
         KRATOS_TRY
 
         RomSystemVectorType dxrom(GetNumberOfROMModes());
-        
+
         const auto solving_timer = BuiltinTimer();
         MathUtils<double>::Solve(rA, dxrom, rb);
         // KRATOS_WATCH(dxrom)
@@ -791,7 +792,7 @@ class ROMBuilderAndSolver : public BuilderAndSolver<TSparseSpace, TDenseSpace, T
     SizeType mNumberOfRomModes;
 
     ///@}
-    ///@name Private operations 
+    ///@name Private operations
     ///@{
 
     /**

applications/RomApplication/custom_utilities/rom_auxiliary_utilities.cpp

@@ -1088,4 +1088,35 @@ void RomAuxiliaryUtilities::GetJPhiElemental(
         }
     }
 
+// Define the static member
+RomAuxiliaryUtilities::NodeBinsType::UniquePointer RomAuxiliaryUtilities::mpBins = nullptr;
+
+
+void RomAuxiliaryUtilities::InitializeBins(NodesPointerSetType& rMasterStructureNodes)
+{
+    NodesPointerSetType::ContainerType& nodes_model_part = rMasterStructureNodes.GetContainer();
+    mpBins = Kratos::make_unique<NodeBinsType>(nodes_model_part.begin(), nodes_model_part.end());
+}
+
+std::unordered_set<int> RomAuxiliaryUtilities::FindNearestNeighbors(std::vector<Node::Pointer> nodesVector)
+{
+    KRATOS_TRY;
+
+    if (!mpBins) {
+        KRATOS_ERROR << "Bins have not been initialized. Call InitializeBins first." << std::endl;
+    }
+
+    std::unordered_set<int> nearestNodeIds; // Using unordered_set for unique node IDs
+
+    for (auto& p_current_node : nodesVector) {
+        NodeType::Pointer found_node = mpBins->SearchNearestPoint(*p_current_node);  // Search for nearest node
+        nearestNodeIds.insert(found_node->Id()); // Insert the found node's ID
+    }
+
+    return nearestNodeIds;
+
+    KRATOS_CATCH("");
+}
+
+
 } // namespace Kratos

applications/RomApplication/custom_utilities/rom_auxiliary_utilities.h

@@ -27,6 +27,7 @@
 #include "includes/ublas_interface.h"
 #include "modified_shape_functions/modified_shape_functions.h"
 #include "processes/find_nodal_neighbours_process.h"
+#include "spatial_containers/bins_dynamic.h"
 
 // Application includes
 #include "rom_application_variables.h"
@@ -58,6 +59,11 @@ class KRATOS_API(ROM_APPLICATION) RomAuxiliaryUtilities
 
     using NodesPointerSetType = ModelPart::NodesContainerType;
 
+    using ResultNodesContainerType = NodesPointerSetType::ContainerType;
+
+    //Bin
+    using NodeBinsType = BinsDynamic<3, NodeType, NodesPointerSetType::ContainerType>;
+
     using ElementFacesMapType = std::unordered_map<
         std::vector<IndexType>,
         std::pair<bool, GeometryPointerType>,
@@ -366,9 +372,37 @@ class KRATOS_API(ROM_APPLICATION) RomAuxiliaryUtilities
         const Element::DofsVectorType& rDofs,
         const Matrix &rJPhi);
 
+    /**
+     * @brief Initializes the bins for the nodes in the master structure.
+     *
+     * This function sets up the spatial bins for efficient nearest neighbor search.
+     *
+     * @param rMasterStructureNodes Reference to the master structure nodes.
+     */
+    static void InitializeBins(NodesPointerSetType& rMasterStructureNodes);
+
+    /**
+     * @brief Finds the nearest neighbors for a set of nodes in a given model part.
+     *
+     * This function locates the closest node in the master structure to each node in the provided vector.
+     * It uses a spatial bin to efficiently search for the nearest neighbor. The IDs of the nearest nodes are
+     * stored in an unordered set to ensure uniqueness.
+     *
+     * @param nodesVector A vector of pointers to the nodes for which the nearest neighbors are to be found.
+     * @return std::unordered_set<int> A set containing unique IDs of the nearest nodes.
+     */
+    static std::unordered_set<int> FindNearestNeighbors(std::vector<Node::Pointer> nodesVector);
+
     ///@}
 
     private:
+        ///@}
+        ///@name Member Variables
+        ///@{
+
+        static NodeBinsType::UniquePointer mpBins;
+
+        ///@}
 
     ///@name Private Static Operations
     ///@{

applications/RomApplication/python_scripts/hrom_training_utility.py

@@ -347,7 +347,6 @@ def AppendHRomWeightsToRomParameters(self):
 
                 # Call the GetConditionIdsNotInHRomModelPart function
                 new_conditions = KratosROM.RomAuxiliaryUtilities.GetConditionIdsNotInHRomModelPart(
-                    root_model_part, # The complete model part
                     conditions_to_include_model_part, # The model part containing the conditions to be included
                     hrom_weights)
 
@@ -384,6 +383,7 @@ def AppendHRomWeightsToRomParameters(self):
 
                 # Call the GetNodalNeighbouringElementIdsNotInHRom function
                 new_nodal_neighbours = KratosROM.RomAuxiliaryUtilities.GetNodalNeighbouringElementIdsNotInHRom(
+                    root_model_part,
                     nodal_neighbours_model_part, # The model part containing the nodal neighbouring elements to be included
                     hrom_weights)