CoordinateElement.h

// Copyright (C) 2018-2020 Garth N. Wells and Chris N. Richardson
//
// This file is part of DOLFINx (https://www.fenicsproject.org)
//
// SPDX-License-Identifier:    LGPL-3.0-or-later
 
#pragma once
 
#include "ElementDofLayout.h"
#include <cstdint>
#include <dolfinx/mesh/cell_types.h>
#include <functional>
#include <memory>
#include <xtensor/xtensor.hpp>
#include <xtl/xspan.hpp>
 
namespace basix
{
class FiniteElement;
}
 
namespace dolfinx::fem
{
 
// FIXME: A dof layout on a reference cell needs to be defined.
 
class CoordinateElement
{
public:
  explicit CoordinateElement(std::shared_ptr<basix::FiniteElement> element);
 
  CoordinateElement(mesh::CellType celltype, int degree);
 
  virtual ~CoordinateElement() = default;
 
  mesh::CellType cell_shape() const;
 
  int topological_dimension() const;
 
  xt::xtensor<double, 4> tabulate(int n, const xt::xtensor<double, 2>& X) const;
 
  void compute_jacobian(const xt::xtensor<double, 4>& dphi,
                        const xt::xtensor<double, 2>& cell_geometry,
                        xt::xtensor<double, 3>& J) const;
 
  void compute_jacobian_inverse(const xt::xtensor<double, 3>& J,
                                xt::xtensor<double, 3>& K) const;
 
  void compute_jacobian_determinant(const xt::xtensor<double, 3>& J,
                                    xt::xtensor<double, 1>& detJ) const;
 
  ElementDofLayout dof_layout() const;
 
  static void push_forward(xt::xtensor<double, 2>& x,
                           const xt::xtensor<double, 2>& cell_geometry,
                           const xt::xtensor<double, 2>& phi);
 
  void pull_back(xt::xtensor<double, 2>& X, xt::xtensor<double, 3>& J,
                 xt::xtensor<double, 1>& detJ, xt::xtensor<double, 3>& K,
                 const xt::xtensor<double, 2>& x,
                 const xt::xtensor<double, 2>& cell_geometry) const;
 
  void permute_dofs(xtl::span<std::int32_t> dofs,
                    const std::uint32_t cell_perm) const;
 
  void unpermute_dofs(xtl::span<std::int32_t> dofs,
                      const std::uint32_t cell_perm) const;
 
  bool needs_dof_permutations() const;
 
  double non_affine_atol = 1.0e-8;
 
  int non_affine_max_its = 10;
 
private:
  // Flag denoting affine map
  bool _is_affine;
 
  // Basix Element
  std::shared_ptr<basix::FiniteElement> _element;
};
} // namespace dolfinx::fem