scalar_polynomials_base.h

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// ------------------------------------------------------------------------
//
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2019 - 2024 by the deal.II authors
//
// This file is part of the deal.II library.
//
// Part of the source code is dual licensed under Apache-2.0 WITH
// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
// governing the source code and code contributions can be found in
// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
//
// ------------------------------------------------------------------------
 
#ifndef dealii_scalar_polynomials_base_h
#define dealii_scalar_polynomials_base_h
 
 
#include <deal.II/base/config.h>
 
#include <deal.II/base/exceptions.h>
#include <deal.II/base/point.h>
#include <deal.II/base/tensor.h>
 
#include <memory>
#include <string>
#include <vector>
 
DEAL_II_NAMESPACE_OPEN
 
template <int dim>
class ScalarPolynomialsBase
{
public:
  ScalarPolynomialsBase(const unsigned int deg,
                        const unsigned int n_polynomials);
 
  ScalarPolynomialsBase(ScalarPolynomialsBase<dim> &&) = default; // NOLINT
 
  ScalarPolynomialsBase(const ScalarPolynomialsBase<dim> &) = default;
 
  virtual ~ScalarPolynomialsBase() = default;
 
  virtual void
  evaluate(const Point<dim>            &unit_point,
           std::vector<double>         &values,
           std::vector<Tensor<1, dim>> &grads,
           std::vector<Tensor<2, dim>> &grad_grads,
           std::vector<Tensor<3, dim>> &third_derivatives,
           std::vector<Tensor<4, dim>> &fourth_derivatives) const = 0;
 
  virtual double
  compute_value(const unsigned int i, const Point<dim> &p) const = 0;
 
  template <int order>
  Tensor<order, dim>
  compute_derivative(const unsigned int i, const Point<dim> &p) const;
 
  virtual Tensor<1, dim>
  compute_1st_derivative(const unsigned int i, const Point<dim> &p) const = 0;
 
  virtual Tensor<2, dim>
  compute_2nd_derivative(const unsigned int i, const Point<dim> &p) const = 0;
 
  virtual Tensor<3, dim>
  compute_3rd_derivative(const unsigned int i, const Point<dim> &p) const = 0;
 
  virtual Tensor<4, dim>
  compute_4th_derivative(const unsigned int i, const Point<dim> &p) const = 0;
 
  virtual Tensor<1, dim>
  compute_grad(const unsigned int /*i*/, const Point<dim> & /*p*/) const = 0;
 
  virtual Tensor<2, dim>
  compute_grad_grad(const unsigned int /*i*/,
                    const Point<dim> & /*p*/) const = 0;
 
  unsigned int
  n() const;
 
  virtual unsigned int
  degree() const;
 
  virtual std::unique_ptr<ScalarPolynomialsBase<dim>>
  clone() const = 0;
 
  virtual std::string
  name() const = 0;
 
  virtual std::size_t
  memory_consumption() const;
 
private:
  const unsigned int polynomial_degree;
 
  const unsigned int n_pols;
};
 
 
 
template <int dim>
inline unsigned int
ScalarPolynomialsBase<dim>::n() const
{
  return n_pols;
}
 
 
 
template <int dim>
inline unsigned int
ScalarPolynomialsBase<dim>::degree() const
{
  return polynomial_degree;
}
 
 
 
template <int dim>
template <int order>
inline Tensor<order, dim>
ScalarPolynomialsBase<dim>::compute_derivative(const unsigned int i,
                                               const Point<dim>  &p) const
{
  if (order == 1)
    {
      auto derivative = compute_1st_derivative(i, p);
      return *reinterpret_cast<Tensor<order, dim> *>(&derivative);
    }
  if (order == 2)
    {
      auto derivative = compute_2nd_derivative(i, p);
      return *reinterpret_cast<Tensor<order, dim> *>(&derivative);
    }
  if (order == 3)
    {
      auto derivative = compute_3rd_derivative(i, p);
      return *reinterpret_cast<Tensor<order, dim> *>(&derivative);
    }
  if (order == 4)
    {
      auto derivative = compute_4th_derivative(i, p);
      return *reinterpret_cast<Tensor<order, dim> *>(&derivative);
    }
  DEAL_II_NOT_IMPLEMENTED();
  Tensor<order, dim> empty;
  return empty;
}
 
DEAL_II_NAMESPACE_CLOSE
 
#endif