tensor_product_polynomials_const.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2012 - 2018 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, 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 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
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#ifndef dealii_tensor_product_polynomials_const_h
#define dealii_tensor_product_polynomials_const_h


#include <deal.II/base/config.h>

#include <deal.II/base/exceptions.h>
#include <deal.II/base/point.h>
#include <deal.II/base/polynomial.h>
#include <deal.II/base/tensor.h>
#include <deal.II/base/tensor_product_polynomials.h>
#include <deal.II/base/utilities.h>

#include <vector>

DEAL_II_NAMESPACE_OPEN


template <int dim>
class TensorProductPolynomialsConst : public TensorProductPolynomials<dim>
{
public:
  static const unsigned int dimension = dim;

  template <class Pol>
  TensorProductPolynomialsConst(const std::vector<Pol> &pols);

  void
  compute(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;

  double
  compute_value(const unsigned int i, const Point<dim> &p) const;

  template <int order>
  Tensor<order, dim>
  compute_derivative(const unsigned int i, const Point<dim> &p) const;

  Tensor<1, dim>
  compute_grad(const unsigned int i, const Point<dim> &p) const;

  Tensor<2, dim>
  compute_grad_grad(const unsigned int i, const Point<dim> &p) const;

  unsigned int
  n() const;
};

/* ---------------- template and inline functions ---------- */

#ifndef DOXYGEN

template <int dim>
template <class Pol>
inline TensorProductPolynomialsConst<dim>::TensorProductPolynomialsConst(
  const std::vector<Pol> &pols)
  : TensorProductPolynomials<dim>(pols)
{
  // append index for renumbering
  this->index_map.push_back(this->n_tensor_pols);
  this->index_map_inverse.push_back(this->n_tensor_pols);
}



template <int dim>
inline unsigned int
TensorProductPolynomialsConst<dim>::n() const
{
  return this->n_tensor_pols + 1;
}



template <>
inline unsigned int
TensorProductPolynomialsConst<0>::n() const
{
  return numbers::invalid_unsigned_int;
}

template <int dim>
template <int order>
Tensor<order, dim>
TensorProductPolynomialsConst<dim>::compute_derivative(
  const unsigned int i,
  const Point<dim> & p) const
{
  const unsigned int max_indices = this->n_tensor_pols;
  Assert(i <= max_indices, ExcInternalError());

  // treat the regular basis functions
  if (i < max_indices)
    return this
      ->TensorProductPolynomials<dim>::template compute_derivative<order>(i, p);
  else
    // this is for the constant function
    return Tensor<order, dim>();
}


#endif // DOXYGEN
DEAL_II_NAMESPACE_CLOSE

#endif