t8_geometry_lagrange.hxx

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/*
  This file is part of t8code.
  t8code is a C library to manage a collection (a forest) of multiple
  connected adaptive space-trees of general element classes in parallel.
 
  Copyright (C) 2024 the developers
 
  t8code is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.
 
  t8code 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 General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with t8code; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
 
#ifndef T8_GEOMETRY_LAGRANGE_HXX
#define T8_GEOMETRY_LAGRANGE_HXX
 
#include <array>
#include <string>
#include <vector>
 
#include <t8.h>
#include <t8_cmesh/t8_cmesh_types.h>
#include <t8_forest/t8_forest_general.h>
#include <t8_geometry/t8_geometry_with_vertices.hxx>
#include <t8_geometry/t8_geometry_with_vertices.h>
 
#define T8_GEOMETRY_MAX_POLYNOMIAL_DEGREE 2
 
struct t8_geometry_lagrange: public t8_geometry_with_vertices
{
 public:
  t8_geometry_lagrange (int dim);
 
  /* Base constructor with no arguments. We need this since it
   * is called from derived class constructors.
   * Sets dimension and name to invalid values. */
  t8_geometry_lagrange (): t8_geometry_with_vertices ()
  {
  }
 
  virtual ~t8_geometry_lagrange ();
 
  inline t8_geometry_type_t
  t8_geom_get_type () const
  {
    return T8_GEOMETRY_TYPE_LAGRANGE;
  };
 
  void
  t8_geom_evaluate (t8_cmesh_t cmesh, t8_gloidx_t gtreeid, const double *ref_coords, const size_t num_points,
                    double *out_coords) const;
 
  virtual void
  t8_geom_evaluate_jacobian (t8_cmesh_t cmesh, t8_gloidx_t gtreeid, const double *ref_coords, const size_t num_points,
                             double *jacobian) const;
 
  virtual void
  t8_geom_load_tree_data (t8_cmesh_t cmesh, t8_gloidx_t gtreeid);
 
 private:
  inline std::vector<double>
  t8_geom_compute_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_s2_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_s3_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_t3_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_t6_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_q4_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_q9_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_h8_basis (const double *ref_point) const;
 
  inline std::vector<double>
  t8_geom_h27_basis (const double *ref_point) const;
 
  const int *degree;
};
 
template <typename T>
std::vector<T>
flatten (const std::vector<std::vector<T>> &vec)
{
  std::vector<T> flattened;
  for (auto const &v : vec) {
    flattened.insert (flattened.end (), v.begin (), v.end ());
  }
  return flattened;
}
 
class t8_lagrange_element {
 public:
  t8_lagrange_element (t8_eclass_t eclass, uint32_t degree, std::vector<double> &nodes);
 
  ~t8_lagrange_element ()
  {
    t8_cmesh_destroy (&cmesh);
  };
 
  t8_eclass_t
  get_type () const;
 
  std::vector<t8_eclass_t>
  face_classes () const;
 
  std::vector<double>
  get_node_coords (uint32_t node) const;
 
  std::vector<std::vector<double>>
  get_node_coords (std::vector<uint32_t> &nodes) const;
 
  std::vector<std::vector<uint32_t>>
  get_face_nodes () const;
 
  std::vector<t8_lagrange_element>
  decompose () const;
 
  std::array<double, T8_ECLASS_MAX_DIM>
  evaluate (const std::array<double, T8_ECLASS_MAX_DIM> &ref_point) const;
 
  std::vector<std::array<double, T8_ECLASS_MAX_DIM>>
  sample (uint32_t n_point) const;
 
  std::array<double, T8_ECLASS_MAX_DIM>
  map_on_face (t8_eclass eclass, const int face_id, const std::array<double, T8_ECLASS_MAX_DIM> &coord) const;
 
  void
  write () const;
 
 private:
  t8_eclass_t eclass;
  const uint32_t degree;
  const std::vector<double> nodes;
  t8_cmesh_t cmesh;
  static constexpr uint32_t lagrange_nodes[T8_ECLASS_COUNT][2] = { { 1, 1 }, { 2, 3 }, { 4, 9 }, { 3, 6 }, { 8, 27 } };
 
  t8_forest_t
  create_uniform_forest (t8_cmesh_t cmesh, uint32_t level) const;
};
 
#endif /* !T8_GEOMETRY_LAGRANGE_HXX */