quadrature.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2018 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// This library 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 2.1 of the License, or (at your option) any later version.

// This library 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 this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



#ifndef LIBMESH_QUADRATURE_H
#define LIBMESH_QUADRATURE_H

// Local includes
#include "libmesh/libmesh_common.h"
#include "libmesh/reference_counted_object.h"
#include "libmesh/point.h"
#include "libmesh/enum_elem_type.h" // INVALID_ELEM
#include "libmesh/enum_order.h" // INVALID_ORDER
#include "libmesh/auto_ptr.h" // deprecated

#ifdef LIBMESH_FORWARD_DECLARE_ENUMS
namespace libMesh
{
enum QuadratureType : int;
}
#else
#include "libmesh/enum_quadrature_type.h"
#endif

// C++ includes
#include <vector>
#include <string>
#include <utility>
#include <memory>

namespace libMesh
{

// forward declarations
class Elem;

class QBase : public ReferenceCountedObject<QBase>
{
protected:

  QBase (unsigned int dim,
         Order order=INVALID_ORDER);

public:

  QBase (const QBase &) = default;
  QBase (QBase &&) = default;
  QBase & operator= (const QBase &) = default;
  QBase & operator= (QBase &&) = default;
  virtual ~QBase() = default;

  virtual QuadratureType type() const = 0;

  static std::unique_ptr<QBase> build (const std::string & name,
                                       const unsigned int dim,
                                       const Order order=INVALID_ORDER);

  static std::unique_ptr<QBase> build (const QuadratureType qt,
                                       const unsigned int dim,
                                       const Order order=INVALID_ORDER);

  ElemType get_elem_type() const { return _type; }

  unsigned int get_p_level() const { return _p_level; }

  unsigned int n_points() const
  {
    libmesh_assert (!_points.empty());
    return cast_int<unsigned int>(_points.size());
  }

  unsigned int get_dim() const { return _dim; }

  const std::vector<Point> & get_points() const { return _points; }

  std::vector<Point> & get_points() { return _points; }

  const std::vector<Real> & get_weights() const { return _weights; }

  std::vector<Real> & get_weights() { return _weights; }

  Point qp(const unsigned int i) const
  {
    libmesh_assert_less (i, _points.size());
    return _points[i];
  }

  Real w(const unsigned int i) const
  {
    libmesh_assert_less (i, _weights.size());
    return _weights[i];
  }

  virtual void init (const ElemType type=INVALID_ELEM,
                     unsigned int p_level=0);

  virtual void init (const Elem & elem,
                     const std::vector<Real> & vertex_distance_func,
                     unsigned int p_level=0);

  Order get_order() const { return static_cast<Order>(_order + _p_level); }

  void print_info(std::ostream & os=libMesh::out) const;

  void scale(std::pair<Real, Real> old_range,
             std::pair<Real, Real> new_range);

  friend std::ostream & operator << (std::ostream & os, const QBase & q);

  virtual bool shapes_need_reinit() { return false; }

  bool allow_rules_with_negative_weights;

protected:


  virtual void init_0D (const ElemType type=INVALID_ELEM,
                        unsigned int p_level=0);

  virtual void init_1D (const ElemType type=INVALID_ELEM,
                        unsigned int p_level=0) = 0;

  virtual void init_2D (const ElemType,
                        unsigned int = 0)
  {
#ifdef DEBUG
    libmesh_error_msg("ERROR: Seems as if this quadrature rule \nis not implemented for 2D.");
#endif
  }

  virtual void init_3D (const ElemType,
                        unsigned int = 0)
  {
#ifdef DEBUG
    libmesh_error_msg("ERROR: Seems as if this quadrature rule \nis not implemented for 3D.");
#endif
  }

  void tensor_product_quad (const QBase & q1D);

  void tensor_product_hex (const QBase & q1D);

  void tensor_product_prism (const QBase & q1D, const QBase & q2D);

  unsigned int _dim;

  Order _order;

  ElemType _type;

  unsigned int _p_level;

  std::vector<Point> _points;

  std::vector<Real> _weights;
};



// ------------------------------------------------------------
// QBase class members

inline
QBase::QBase(unsigned int d,
             Order o) :
  allow_rules_with_negative_weights(true),
  _dim(d),
  _order(o),
  _type(INVALID_ELEM),
  _p_level(0)
{
}




inline
void QBase::print_info(std::ostream & os) const
{
  libmesh_assert(!_points.empty());
  libmesh_assert(!_weights.empty());

  Real summed_weights=0;
  os << "N_Q_Points=" << this->n_points() << std::endl << std::endl;
  for (unsigned int qpoint=0; qpoint<this->n_points(); qpoint++)
    {
      os << " Point " << qpoint << ":\n"
         << "  "
         << _points[qpoint]
         << "\n Weight:\n "
         << "  w=" << _weights[qpoint] << "\n" << std::endl;

      summed_weights += _weights[qpoint];
    }
  os << "Summed Weights: " << summed_weights << std::endl;
}

} // namespace libMesh

#endif // LIBMESH_QUADRATURE_H