Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2026 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : 
      20             : #ifndef LIBMESH_QUADRATURE_GRID_H
      21             : #define LIBMESH_QUADRATURE_GRID_H
      22             : 
      23             : // Local includes
      24             : #include "libmesh/quadrature.h"
      25             : 
      26             : namespace libMesh
      27             : {
      28             : 
      29             : /**
      30             :  * This class creates quadrature points on a uniform grid with
      31             :  * order+1 intervals per edge.  On edges, quadrilaterals, and
      32             :  * hexahedra, the points are the midpoints of the grid cells, giving
      33             :  * (order+1)^dim points.  On triangles, tetrahedra, and pyramids, the
      34             :  * element is uniformly refined into congruent or equal-volume
      35             :  * triangles or tetrahedra, and the points are their centroids:
      36             :  * (order+1)^2 points on triangles, (order+1)^3 on tetrahedra, and
      37             :  * 2*(order+1)^3 on pyramids.  Prisms use the tensor product of the
      38             :  * edge and triangle rules.  In every case all points are strictly
      39             :  * interior and have equal weights, and linear functions are
      40             :  * integrated exactly.
      41             :  *
      42             :  * Unlike most libMesh quadrature rules, QGrid does *not* reduce the
      43             :  * integration error exponentially on smooth functions as you increase
      44             :  * the quadrature order.  Instead, it reduces the error quadratically.
      45             :  * However, this error reduction is more reliable on non-smooth
      46             :  * functions.
      47             :  *
      48             :  * This quadrature type may be useful if you are integrating functions
      49             :  * which have discontinuities or discontinuous derivatives on scales
      50             :  * smaller than your element size.
      51             :  *
      52             :  * \author Roy Stogner
      53             :  * \date 2005
      54             :  * \brief Implements grid-based quadrature rules suitable for non-smooth functions.
      55             :  */
      56             : class QGrid final : public QBase
      57             : {
      58             : public:
      59             : 
      60             :   /**
      61             :    * Constructor.  Declares the order of the quadrature rule.
      62             :    */
      63      160972 :   QGrid (unsigned int dim,
      64      160972 :          Order order=INVALID_ORDER) :
      65      160972 :     QBase(dim, order)
      66             :   {
      67      160972 :     if (dim == 1)
      68        2689 :       init(EDGE2);
      69      160972 :   }
      70             : 
      71             :   /**
      72             :    * Copy/move ctor, copy/move assignment operator, and destructor are
      73             :    * all explicitly defaulted for this simple class.
      74             :    */
      75           0 :   QGrid (const QGrid &) = default;
      76             :   QGrid (QGrid &&) = default;
      77             :   QGrid & operator= (const QGrid &) = default;
      78             :   QGrid & operator= (QGrid &&) = default;
      79      161138 :   virtual ~QGrid() = default;
      80             : 
      81             :   /**
      82             :    * \returns \p QGRID.
      83             :    */
      84             :   virtual QuadratureType type() const override;
      85             : 
      86             :   virtual std::unique_ptr<QBase> clone() const override;
      87             : 
      88             : private:
      89             : 
      90             :   virtual void init_1D () override;
      91             :   virtual void init_2D () override;
      92             :   virtual void init_3D () override;
      93             : };
      94             : 
      95             : } // namespace libMesh
      96             : 
      97             : #endif // LIBMESH_QUADRATURE_GRID_H