MeshNodes.hpp

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#pragma once
 
#include <polyfem/mesh/Mesh.hpp>
#include <polyfem/utils/Types.hpp>
 
#include <polyfem/mesh/mesh2D/Navigation.hpp>
#include <polyfem/mesh/mesh3D/Navigation3D.hpp>
 
#include <Eigen/Dense>
 
namespace polyfem
{
    namespace mesh
    {
 
        // Wrapper for lazy assignment of node ids
        class MeshNodes
        {
        public:
            MeshNodes(const Mesh &mesh, const bool has_poly, const bool connect_nodes, const int max_nodes_per_edge, const int max_nodes_per_face, const int max_nodes_per_cell = 0);
 
            // Number of currently assigned nodes
            int n_nodes() const { return node_to_primitive_.size(); }
 
            // Lazy retrieval of node ids
            int node_id_from_vertex(int v);
            int node_id_from_edge(int e);
            int node_id_from_face(int f);
            int node_id_from_cell(int c);
            int node_id_from_primitive(int primitive_id);
 
            std::vector<int> node_ids_from_edge(const Navigation::Index &index, const int n_new_nodes);
            std::vector<int> node_ids_from_face(const Navigation::Index &index, const int n_new_nodes);
 
            std::vector<int> node_ids_from_edge(const Navigation3D::Index &index, const int n_new_nodes);
            std::vector<int> node_ids_from_face(const Navigation3D::Index &index, const int n_new_nodes);
            std::vector<int> node_ids_from_cell(const Navigation3D::Index &index, const int n_new_nodes);
 
            // Packed id from primitive
            int primitive_from_vertex(int v) const { return v; }
            int primitive_from_edge(int e) const { return edge_offset_ + e; }
            int primitive_from_face(int f) const { return face_offset_ + f; }
            int primitive_from_cell(int c) const { return cell_offset_ + c; }
 
            bool is_vertex_node(int i) const { return i >= 0 && i < edge_offset_; }
            bool is_edge_node(int i) const { return i >= edge_offset_ && i < face_offset_; }
            bool is_face_node(int i) const { return i >= face_offset_ && i < cell_offset_; }
            bool is_cell_node(int i) const { return i >= cell_offset_; }
 
            int num_vertex_nodes() const { return count_nonnegative_nodes(0, edge_offset_); }
            int num_edge_nodes() const { return count_nonnegative_nodes(edge_offset_, face_offset_); }
            int num_face_nodes() const { return count_nonnegative_nodes(face_offset_, cell_offset_); }
            int num_cell_nodes() const { return count_nonnegative_nodes(cell_offset_, n_nodes()); }
 
            // Primitive id from node id
            int vertex_from_node_id(int node_id) const;
            int edge_from_node_id(int node_id) const;
            int face_from_node_id(int node_id) const;
            int cell_from_node_id(int node_id) const;
 
            const std::vector<int> &primitive_to_node() const { return primitive_to_node_; }
            const std::vector<int> &node_to_primitive_gid() const { return node_to_primitive_gid_; }
            const std::vector<int> &node_to_primitive() const { return node_to_primitive_; }
 
            // Node position from node id
            RowVectorNd node_position(int node_id) const { return nodes_.row(node_to_primitive_[node_id]); }
 
            // Whether a node is on the mesh boundary or not
            bool is_boundary(int node_id) const { return is_boundary_[node_to_primitive_[node_id]]; }
            bool is_primitive_boundary(int primitive) const { return is_boundary_[primitive]; }
 
            // Whether an edge node (in 2D) or face node (in 3D) is at the interface with a polytope
            bool is_interface(int node_id) const { return is_interface_[node_to_primitive_[node_id]]; }
            bool is_primitive_interface(int primitive) const { return is_interface_[primitive]; }
 
            // Either boundary or interface
            bool is_boundary_or_interface(const int node_id) const { return is_boundary(node_id) || is_interface(node_id); }
 
            // Retrieve a list of nodes which are marked as boundary
            std::vector<int> boundary_nodes() const;
 
        private:
            int count_nonnegative_nodes(int start_i, int end_i) const;
 
            const Mesh &mesh_;
            const bool connect_nodes_;
            // Offset to pack primitives ids into a single vector
            const int edge_offset_;
            const int face_offset_;
            const int cell_offset_;
 
            const int max_nodes_per_edge_;
            const int max_nodes_per_face_;
            const int max_nodes_per_cell_;
 
            // Map primitives to nodes back and forth
            std::vector<int> primitive_to_node_;     // #v + #e + #f + #c
            std::vector<int> node_to_primitive_;     // #assigned nodes
            std::vector<int> node_to_primitive_gid_; // #assigned nodes
 
            // Precomputed node data (#v + #e + #f + #c)
            Eigen::MatrixXd nodes_;
            std::vector<bool> is_boundary_;
            std::vector<bool> is_interface_;
        };
    } // namespace mesh
} // namespace polyfem