quadrature.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2025 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

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

// We used to have additional arguments to the init_0D, init_1D, etc.
// classes, but they became unused after QBase members made them
// redundant, so they were deprecated and eventually removed.  Users'
// derived classes that need to compile against both old and new
// libMesh version can test this macro to determine what signature
// their overrides should have.
#define LIBMESH_QBASE_INIT_ARGUMENTS_REMOVED

namespace libMesh
{

// forward declarations
class Elem;
enum QuadratureType : int;

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 std::unique_ptr<QBase> clone() const;

  virtual QuadratureType type() const = 0;

  static std::unique_ptr<QBase> build (std::string_view 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 size() const
  {
    return n_points();
  }

  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 Elem & e,
                     unsigned int p_level=invalid_uint);

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

  virtual void init (const QBase & other_rule);

  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 + 2 * _p_level); }

  Order get_base_order() const { return static_cast<Order>(_order); }

  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;

  bool allow_nodal_pyramid_quadrature;

protected:


  virtual void init_0D ();

  virtual void init_1D () = 0;

  virtual void init_2D ();

  virtual void init_3D ();

  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;

  const Elem * _elem;

  unsigned int _p_level;

  std::vector<Point> _points;

  std::vector<Real> _weights;
};

} // namespace libMesh

#endif // LIBMESH_QUADRATURE_H