TetrahedronCell.h

// Copyright (C) 2006-2017 Anders Logg
//
// This file is part of DOLFIN.
//
// DOLFIN is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// DOLFIN is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with DOLFIN. If not, see <http://www.gnu.org/licenses/>.
//
// Modified by Johan Hoffman, 2006.
// Modified by Garth N. Wells, 2006.
// Modified by Kristoffer Selim, 2008.
//
// First added:  2006-06-05
// Last changed: 2017-09-26

#ifndef __TETRAHEDRON_CELL_H
#define __TETRAHEDRON_CELL_H

#include <vector>
#include <boost/multi_array.hpp>

#include "CellType.h"

namespace dolfin
{

  class Cell;


  class TetrahedronCell : public CellType
  {
  public:

    TetrahedronCell() : CellType(Type::tetrahedron, Type::triangle) {}

    bool is_simplex() const
    { return true; }

    std::size_t dim() const;

    std::size_t num_entities(std::size_t dim) const;

    std::size_t num_vertices(std::size_t dim) const;

    std::size_t orientation(const Cell& cell) const;

    void create_entities(boost::multi_array<unsigned int, 2>& e,
                         std::size_t dim, const unsigned int* v) const;

    double volume(const MeshEntity& tetrahedron) const;

    double circumradius(const MeshEntity& tetrahedron) const;

    double squared_distance(const Cell& cell, const Point& point) const;

    double normal(const Cell& cell, std::size_t facet, std::size_t i) const;

    Point normal(const Cell& cell, std::size_t facet) const;

    Point cell_normal(const Cell& cell) const;

    double facet_area(const Cell& cell, std::size_t facet) const;

    void order(Cell& cell, const std::vector<std::int64_t>&
               local_to_global_vertex_indices) const;

    bool collides(const Cell& cell, const Point& point) const;

    bool collides(const Cell& cell, const MeshEntity& entity) const;

    std::string description(bool plural) const;

    std::vector<std::int8_t> vtk_mapping() const
    { return {0, 1, 2, 3}; }

  private:

    // Find local index of edge i according to ordering convention
    std::size_t find_edge(std::size_t i, const Cell& cell) const;

    // Check whether point is outside region defined by facet ABC.
    // The fourth vertex is needed to define the orientation.
    bool point_outside_of_plane(const Point& point,
                                const Point& A,
                                const Point& B,
                                const Point& C,
                                const Point& D) const;

  };

}

#endif