Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : 
      20             : #ifndef LIBMESH_CELL_TET4_H
      21             : #define LIBMESH_CELL_TET4_H
      22             : 
      23             : // Local includes
      24             : #include "libmesh/cell_tet.h"
      25             : 
      26             : namespace libMesh
      27             : {
      28             : 
      29             : /**
      30             :  * The \p Tet4 is an element in 3D composed of 4 nodes.  It is
      31             :  * numbered like this:
      32             :  *
      33             :  * \verbatim
      34             :  *   TET4:
      35             :  *         3
      36             :  *         o                 zeta
      37             :  *        /|\                 ^
      38             :  *       / | \                |
      39             :  *      /  |  \               |
      40             :  *   0 o...|...o 2            o---> eta
      41             :  *      \  |  /                \
      42             :  *       \ | /                  \
      43             :  *        \|/                    xi (out of page)
      44             :  *         o
      45             :  *         1
      46             :  * \endverbatim
      47             :  *
      48             :  * (xi, eta, zeta): { 0 <= xi   <= 1
      49             :  *                  { 0 <= eta  <= 1
      50             :  *                  { 0 <= zeta <= 1
      51             :  *                  { xi + eta + zeta <= 1
      52             :  * are the reference element coordinates associated with the given
      53             :  * numbering.
      54             :  *
      55             :  * \author Benjamin S. Kirk
      56             :  * \date 2002
      57             :  * \brief A 3D tetrahedral element with 4 nodes.
      58             :  */
      59             : class Tet4 final : public Tet
      60             : {
      61             : public:
      62             : 
      63             :   /**
      64             :    * Constructor.  By default this element has no parent.
      65             :    */
      66             :   explicit
      67    14819362 :   Tet4 (Elem * p=nullptr) :
      68    14819362 :     Tet(num_nodes, p, _nodelinks_data)
      69    14819362 :   {}
      70             : 
      71             :   Tet4 (Tet4 &&) = delete;
      72             :   Tet4 (const Tet4 &) = delete;
      73             :   Tet4 & operator= (const Tet4 &) = delete;
      74             :   Tet4 & operator= (Tet4 &&) = delete;
      75    15669437 :   virtual ~Tet4() = default;
      76             : 
      77             :   /**
      78             :    * \returns \p TET4.
      79             :    */
      80   189028297 :   virtual ElemType type () const override { return TET4; }
      81             : 
      82             :   /**
      83             :    * \returns 4.
      84             :    */
      85   131548740 :   virtual unsigned int n_nodes() const override { return num_nodes; }
      86             : 
      87             :   /**
      88             :    * \returns 1.
      89             :    */
      90        8685 :   virtual unsigned int n_sub_elem() const override { return 1; }
      91             : 
      92             :   /**
      93             :    * \returns \p true if the specified (local) node number is a vertex.
      94             :    */
      95             :   virtual bool is_vertex(const unsigned int i) const override;
      96             : 
      97             :   /**
      98             :    * \returns \p true if the specified (local) node number is an edge.
      99             :    */
     100             :   virtual bool is_edge(const unsigned int i) const override;
     101             : 
     102             :   /**
     103             :    * \returns \p true if the specified (local) node number is a face.
     104             :    */
     105             :   virtual bool is_face(const unsigned int i) const override;
     106             : 
     107             :   /**
     108             :    * \returns \p true if the specified (local) node number is on the
     109             :    * specified side.
     110             :    */
     111             :   virtual bool is_node_on_side(const unsigned int n,
     112             :                                const unsigned int s) const override;
     113             : 
     114             :   virtual std::vector<unsigned int> nodes_on_side(const unsigned int s) const override;
     115             : 
     116             :   virtual std::vector<unsigned int> nodes_on_edge(const unsigned int e) const override;
     117             : 
     118             :   /**
     119             :    * \returns \p true if the specified (local) node number is on the
     120             :    * specified edge.
     121             :    */
     122             :   virtual bool is_node_on_edge(const unsigned int n,
     123             :                                const unsigned int e) const override;
     124             : 
     125             :   /**
     126             :    * \returns \p true if the specified child is on the
     127             :    * specified side.
     128             :    */
     129             :   virtual bool is_child_on_side(const unsigned int c,
     130             :                                 const unsigned int s) const override;
     131             : 
     132             :   /**
     133             :    * \returns \p true if the element map is definitely affine within
     134             :    * numerical tolerances.
     135             :    */
     136     2106316 :   virtual bool has_affine_map () const override { return true; }
     137             : 
     138             :   /**
     139             :    * \returns \p true if the element has non-zero volume(), false otherwise.
     140             :    */
     141             :   virtual bool has_invertible_map(Real tol) const override;
     142             : 
     143             :   /**
     144             :    * \returns \p true if the Lagrange shape functions on this element
     145             :    * are linear.
     146             :    */
     147      156914 :   virtual bool is_linear () const override { return true; }
     148             : 
     149             :   /**
     150             :    * \returns FIRST.
     151             :    */
     152             :   virtual Order default_order() const override;
     153             : 
     154             :   /**
     155             :    * Builds a \p TRI3 built coincident with face i.
     156             :    * The \p std::unique_ptr<Elem> handles the memory aspect.
     157             :    */
     158             :   virtual std::unique_ptr<Elem> build_side_ptr (const unsigned int i) override;
     159             : 
     160             :   /**
     161             :    * Rebuilds a TRI3 built coincident with face i.
     162             :    */
     163             :   virtual void build_side_ptr (std::unique_ptr<Elem> & elem,
     164             :                                const unsigned int i) override;
     165             : 
     166             :   // Avoid hiding deprecated version with different signature
     167             :   using Elem::build_side_ptr;
     168             : 
     169             :   /**
     170             :    * Builds a \p EDGE2 built coincident with face i.
     171             :    * The \p std::unique_ptr<Elem> handles the memory aspect.
     172             :    */
     173             :   virtual std::unique_ptr<Elem> build_edge_ptr (const unsigned int i) override;
     174             : 
     175             :   /**
     176             :    * Rebuilds a \p EDGE2 coincident with edge i.
     177             :    */
     178             :   virtual void build_edge_ptr (std::unique_ptr<Elem> & edge, const unsigned int i) override;
     179             : 
     180             :   virtual void connectivity(const unsigned int sc,
     181             :                             const IOPackage iop,
     182             :                             std::vector<dof_id_type> & conn) const override;
     183             : 
     184             :   /**
     185             :    * Geometric constants for Tet4.
     186             :    */
     187             :   static const int num_nodes = 4;
     188             :   static const int nodes_per_side = 3;
     189             :   static const int nodes_per_edge = 2;
     190             : 
     191             :   /**
     192             :    * This maps the \f$ j^{th} \f$ node of the \f$ i^{th} \f$ side to
     193             :    * element node numbers.
     194             :    */
     195             :   static const unsigned int side_nodes_map[num_sides][nodes_per_side];
     196             : 
     197             :   /**
     198             :    * This maps the \f$ j^{th} \f$ node of the \f$ i^{th} \f$ edge to
     199             :    * element node numbers.
     200             :    */
     201             :   static const unsigned int edge_nodes_map[num_edges][nodes_per_edge];
     202             : 
     203             :   /**
     204             :    * The centroid of a 4-node tetrahedron is simply given by the
     205             :    * average of its vertex positions.
     206             :    */
     207             :   virtual Point true_centroid () const override;
     208             : 
     209             :   /**
     210             :    * An optimized method for computing the area of a
     211             :    * 4-node tetrahedron.
     212             :    */
     213             :   virtual Real volume () const override;
     214             : 
     215             :   /**
     216             :    * \returns The min and max *dihedral* angles for the tetrahedron.
     217             :    *
     218             :    * \note There are 6 dihedral angles (angles between the planar
     219             :    * faces) for the Tet4.  Dihedral angles near 180 deg. are generally
     220             :    * bad for interpolation.  Small dihedral angles are not necessarily
     221             :    * bad for interpolation, but they can affect the stiffness matrix
     222             :    * condition number.
     223             :    */
     224             :   std::pair<Real, Real> min_and_max_angle() const;
     225             : 
     226             :   /**
     227             :    * Don't hide Tet::key(side) defined in the base class.
     228             :    */
     229             :   using Tet::key;
     230             : 
     231             :   /**
     232             :    * \returns An id associated with the global node ids of this
     233             :    * element.  The id is not necessarily unique, but should be
     234             :    * close.
     235             :    */
     236             :   virtual dof_id_type key () const override;
     237             : 
     238             :   /**
     239             :    * Uses simple geometric tests to determine if the point p is inside
     240             :    * the tetrahedron.
     241             :    */
     242             :   virtual bool contains_point (const Point & p, Real tol) const override;
     243             : 
     244             :   virtual void permute(unsigned int perm_num) override final;
     245             : 
     246             :   virtual void flip(BoundaryInfo *) override final;
     247             : 
     248             :   ElemType side_type (const unsigned int s) const override final;
     249             : 
     250             : protected:
     251             : 
     252             :   /**
     253             :    * Data for links to nodes.
     254             :    */
     255             :   Node * _nodelinks_data[num_nodes];
     256             : 
     257             : 
     258             : 
     259             : #ifdef LIBMESH_ENABLE_AMR
     260             : 
     261             :   /**
     262             :    * Matrix used to create the elements children.
     263             :    */
     264             :   virtual Real embedding_matrix (const unsigned int i,
     265             :                                  const unsigned int j,
     266             :                                  const unsigned int k) const override;
     267             : 
     268             :   /**
     269             :    * Matrix that computes new nodal locations/solution values
     270             :    * from current nodes/solution.
     271             :    */
     272             :   static const Real _embedding_matrix[num_children][num_nodes][num_nodes];
     273             : 
     274     7014604 :   LIBMESH_ENABLE_TOPOLOGY_CACHES;
     275             : 
     276             : #endif
     277             : 
     278             : };
     279             : 
     280             : } // namespace libMesh
     281             : 
     282             : 
     283             : #endif // LIBMESH_CELL_TET4_H