macrogrid.hh

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// SPDX-FileCopyrightText: Copyright © DUNE Project contributors, see file LICENSE.md in module root
// SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception
// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_DGF_MACROGRID_HH
#define DUNE_DGF_MACROGRID_HH
 
 
#include <iostream>
 
#include <dune/common/parallel/mpihelper.hh>
#include <dune/grid/io/file/dgfparser/parser.hh>
 
 
namespace Dune
{
  // forward declarations
  // --------------------
  class DuneGridFormatParser;
 
  class MacroGrid
    : protected DuneGridFormatParser
  {
    template< class GridType >
    friend struct DGFGridFactory;
 
  public:
    typedef MPIHelper::MPICommunicator MPICommunicatorType;
 
  protected:
    MacroGrid(const char* filename, MPICommunicatorType MPICOMM = MPIHelper::getCommunicator())
      : DuneGridFormatParser( rank(MPICOMM), size(MPICOMM) )
        , filename_(filename)
        , MPICOMM_(MPICOMM) {}
 
    MacroGrid(MPICommunicatorType MPICOMM = MPIHelper::getCommunicator())
      : DuneGridFormatParser( rank(MPICOMM), size(MPICOMM) )
        , filename_(0)
        , MPICOMM_(MPICOMM) {}
 
    template <class GridType>
    inline GridType * createGrid ()
    {
      return Impl<GridType>::generate(*this,filename_,MPICOMM_);
    }
  private:
    static int rank( [[maybe_unused]] MPICommunicatorType MPICOMM )
    {
      int rank = 0;
#if HAVE_MPI
      MPI_Comm_rank( MPICOMM, &rank );
#endif
      return rank;
    }
    static int size( [[maybe_unused]] MPICommunicatorType MPICOMM )
    {
      int size = 1;
#if HAVE_MPI
      MPI_Comm_size( MPICOMM, &size );
#endif
      return size;
    }
    template< class GridType >
    struct Impl
    {
      static const bool hasDGFFactory = (GridType::dimension<0);
      static GridType* generate(MacroGrid& /*mg*/,
                                const char* /*filename*/, [[maybe_unused]] MPICommunicatorType MPICOMM = MPIHelper::getCommunicator() )
      {
        // make assertion depend on the template argument but always evaluate to false
        static_assert( hasDGFFactory, "DGF grid factory missing. Did you forget to add the corresponding dgf header?");
      }
    };
 
    const char* filename_;
    MPICommunicatorType MPICOMM_;
 
    // provide check to see if Impl<GridType> was overloaded
    template<class T, class = void>
    struct ImplHasDGFFactory : std::true_type {}; // absent: specialized Impl, assume available
    template<class T>
    struct ImplHasDGFFactory<T, std::void_t<decltype(Impl<T>::hasDGFFactory)> > : std::bool_constant<Impl<T>::hasDGFFactory> {};
 
    public:
    template<class GridType> static constexpr bool noDGFFactory = !ImplHasDGFFactory<GridType>::value;
  };
 
} // end namespace Dune
 
#endif