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             : #ifndef LIBMESH_CENTROID_PARTITIONER_H
      20             : #define LIBMESH_CENTROID_PARTITIONER_H
      21             : 
      22             : // Local includes
      23             : #include "libmesh/partitioner.h"
      24             : #include "libmesh/point.h"
      25             : 
      26             : // C++ includes
      27             : #include <memory>
      28             : #include <utility> // pair
      29             : #include <vector>
      30             : 
      31             : namespace libMesh
      32             : {
      33             : 
      34             : // Forward declarations
      35             : class Elem;
      36             : 
      37             : /**
      38             :  * Partitions the Mesh based on the locations of element vertex averages.
      39             :  * You must define what you mean by "less than" for the list of
      40             :  * element vertex averages, e.g. if you only care about distance in the
      41             :  * z-direction, you would define "less than" differently than if you
      42             :  * cared about radial distance.
      43             :  *
      44             :  * \note The name of this partitioner is historical: we do not
      45             :  * partition based on the "true" geometric centroid since the vertex
      46             :  * average is much easier to compute and works just as well as far as
      47             :  * partitioning is concerned.
      48             :  *
      49             :  * \author John W. Peterson
      50             :  * \author Benjamin S. Kirk
      51             :  * \date 2003
      52             :  */
      53             : class CentroidPartitioner : public Partitioner
      54             : {
      55             : public:
      56             : 
      57             :   /**
      58             :    * A typedef which controls the sorting method used for ordering the
      59             :    * vertex averages. If e.g. \p X is chosen, then the vertex averages will be
      60             :    * sorted according to their x-coordinate.
      61             :    */
      62             :   enum CentroidSortMethod {X=0,
      63             :                            Y,
      64             :                            Z,
      65             :                            RADIAL,
      66             :                            INVALID_METHOD};
      67             : 
      68             :   /**
      69             :    * Constructor.  Takes the \p CentroidSortMethod to use, which
      70             :    * defaults to \p X ordering.
      71             :    */
      72             :   explicit
      73          80 :   CentroidPartitioner (const CentroidSortMethod sm=X) : _sort_method(sm) {}
      74             : 
      75             :   /**
      76             :    * Copy/move ctor, copy/move assignment operator, and destructor are
      77             :    * all explicitly defaulted for this class.
      78             :    */
      79          56 :   CentroidPartitioner (const CentroidPartitioner &) = default;
      80             :   CentroidPartitioner (CentroidPartitioner &&) = default;
      81             :   CentroidPartitioner & operator= (const CentroidPartitioner &) = default;
      82             :   CentroidPartitioner & operator= (CentroidPartitioner &&) = default;
      83         144 :   virtual ~CentroidPartitioner() = default;
      84             : 
      85             :   virtual PartitionerType type () const override;
      86             : 
      87             :   /**
      88             :    * \returns A copy of this partitioner wrapped in a smart pointer.
      89             :    */
      90          56 :   virtual std::unique_ptr<Partitioner> clone () const override
      91             :   {
      92          56 :     return std::make_unique<CentroidPartitioner>(*this);
      93             :   }
      94             : 
      95             :   /**
      96             :    * Elements are assigned from a sort of their vertex averages, with no reference to the
      97             :    * partitioning the mesh arrives with.
      98             :    */
      99         301 :   virtual bool partitions_from_scratch () const override { return true; }
     100             : 
     101             :   /**
     102             :    * Getter for the current sorting method.
     103             :    */
     104         196 :   CentroidSortMethod sort_method () const { return _sort_method; }
     105             : 
     106             :   /**
     107             :    * Setter for the current sorting method.
     108             :    */
     109             :   void set_sort_method (const CentroidSortMethod sm) { _sort_method = sm; }
     110             : 
     111             :   /**
     112             :    * Called by the SubdomainPartitioner to partition elements in the range (it, end).
     113             :    */
     114             :   virtual void partition_range(MeshBase & mesh,
     115             :                                MeshBase::element_iterator it,
     116             :                                MeshBase::element_iterator end,
     117             :                                const unsigned int n) override;
     118             : 
     119             : protected:
     120             : 
     121             :   /**
     122             :    * Partitions the mesh into n subdomains.
     123             :    */
     124             :   virtual void _do_partition (MeshBase & mesh,
     125             :                               const unsigned int n) override;
     126             : 
     127             : private:
     128             : 
     129             :   /**
     130             :    * Computes a list of element vertex averages for the mesh.
     131             :    */
     132             :   void compute_vertex_avgs (MeshBase::element_iterator it,
     133             :                             MeshBase::element_iterator end);
     134             : 
     135             :   /**
     136             :    * Helper function which sorts by the vertex average's x-coordinate in the
     137             :    * internal std::sort call.
     138             :    */
     139             :   static bool sort_x (const std::pair<Point, Elem *> & lhs,
     140             :                       const std::pair<Point, Elem *> & rhs);
     141             : 
     142             :   /**
     143             :    * Helper function which sorts by the vertex average's y-coordinate in the
     144             :    * internal std::sort call.
     145             :    */
     146             :   static bool sort_y (const std::pair<Point, Elem *> & lhs,
     147             :                       const std::pair<Point, Elem *> & rhs);
     148             : 
     149             :   /**
     150             :    * Helper function which sorts by the vertex average's z-coordinate in the
     151             :    * internal std::sort call.
     152             :    */
     153             :   static bool sort_z (const std::pair<Point, Elem *> & lhs,
     154             :                       const std::pair<Point, Elem *> & rhs);
     155             : 
     156             :   /**
     157             :    * Helper function which sorts by the vertex averages's distance from the
     158             :    * origin in the internal std::sort call.
     159             :    */
     160             :   static bool sort_radial (const std::pair<Point, Elem *> & lhs,
     161             :                            const std::pair<Point, Elem *> & rhs);
     162             : 
     163             :   /**
     164             :    * Flag indicating the type of sort method we are using.
     165             :    */
     166             :   CentroidSortMethod _sort_method;
     167             : 
     168             :   /**
     169             :    * Vector which holds pairs of vertex averages and their respective
     170             :    * element pointers.
     171             :    */
     172             :   std::vector<std::pair<Point, Elem *>> _elem_vertex_avgs;
     173             : };
     174             : 
     175             : } // namespace libMesh
     176             : 
     177             : #endif // LIBMESH_CENTROID_PARTITIONER_H