space/common/dataprojection/default.hh

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#ifndef DUNE_FEM_HPDG_SPACE_COMMON_DATAPROJECTION_DEFAULT_HH
#define DUNE_FEM_HPDG_SPACE_COMMON_DATAPROJECTION_DEFAULT_HH
 
#include <cassert>
#include <cstddef>
 
#include <functional>
#include <vector>
 
#include <dune/common/dynvector.hh>
 
#include <dune/fem/function/localfunction/localfunction.hh>
#include <dune/fem/function/localfunction/const.hh>
#include <dune/fem/function/localfunction/mutable.hh>
#include <dune/fem/space/common/localinterpolation.hh>
 
#include "dataprojection.hh"
 
namespace Dune
{
 
  namespace Fem
  {
 
    namespace hpDG
    {
 
      // DefaultDataProjection
      // ---------------------
 
      template< class DiscreteFunction >
      class DefaultDataProjection
      : public DataProjection< typename DiscreteFunction::DiscreteFunctionSpaceType, DefaultDataProjection< DiscreteFunction > >
      {
        using ThisType = DefaultDataProjection< DiscreteFunction >;
        using BaseType = DataProjection< typename DiscreteFunction::DiscreteFunctionSpaceType, DefaultDataProjection< DiscreteFunction > >;
 
      public:
        using DiscreteFunctionSpaceType = typename BaseType::DiscreteFunctionSpaceType;
        using BasisFunctionSetType = typename BaseType::BasisFunctionSetType;
        using EntityType = typename BaseType::EntityType;
 
      private:
        using RangeFieldType = typename DiscreteFunction::RangeFieldType;
        using LocalDofVectorType = Dune::DynamicVector< RangeFieldType >;
        using LocalFunctionType = Dune::Fem::LocalFunction< BasisFunctionSetType, LocalDofVectorType >;
 
        static const std::size_t localBlockSize = DiscreteFunctionSpaceType::localBlockSize;
        typedef LocalInterpolation< DiscreteFunctionSpaceType > LocalInterpolationType;
 
      public:
        explicit DefaultDataProjection ( DiscreteFunction &discreteFunction )
          : discreteFunction_( discreteFunction )
        {
          discreteFunction_.get().enableDofCompression();
        }
 
#ifndef DOXYGEN
 
        DefaultDataProjection ( const ThisType & ) = delete;
 
        DefaultDataProjection ( ThisType && ) = default;
 
        ThisType &operator= ( const ThisType & ) = delete;
 
        ThisType &operator= ( ThisType && ) = default;
 
#endif // #ifndef DOXYGEN
 
        void operator() ( const EntityType &entity,
                          const BasisFunctionSetType &prior,
                          const BasisFunctionSetType &present,
                          const std::vector< std::size_t > &origin,
                          const std::vector< std::size_t > &destination )
        {
          LocalFunctionType localFunc( prior );
          read( origin, localFunc.localDofVector() );
 
          assert( present.size() == space().basisFunctionSet( entity ).size() );
          LocalDofVectorType localDofVector( present.size() );
 
          LocalInterpolationType& ip = this->interpolation();
          auto guard = bindGuard( ip, entity );
          ip( localFunc, localDofVector );
 
          write( destination, localDofVector );
        }
 
        template <class TemporaryStorage>
        void operator () ( TemporaryStorage& tmp )
        {
          auto& df = discreteFunction();
 
          // copy dofs to temporary storage, old order still exists
          auto dfit = df.dbegin();
          const auto endtmp = tmp.dend();
          for( auto it = tmp.dbegin(); it != endtmp; ++it, ++dfit )
          {
            assert( dfit != df.dend() );
            *it = *dfit;
          }
 
          ConstLocalFunction< TemporaryStorage > tmpLF( tmp );
          MutableLocalFunction< DiscreteFunction > lf( df );
          LocalInterpolationType interpolation( df.space() );
 
          // interpolate to new space, this can be a
          // Lagrange interpolation or a L2 projection, both locally
          const auto end = df.space().end();
          for( auto it = df.space().begin(); it != end; ++it )
          {
            const auto& entity = *it;
 
            auto tguard = bindGuard( tmpLF, entity );
            auto lguard = bindGuard( lf, entity );
 
            // if size is the same we can just copy the dof values
            if( tmpLF.size() == lf.size() )
            {
              lf.assign( tmpLF );
            }
            else
            {
              auto iguard = bindGuard( interpolation, entity );
              // otherwise a local interpolation is needed
              interpolation( tmpLF, lf );
            }
          }
        }
 
        template< class Communicator >
        void addToList ( Communicator &comm )
        {
          comm.addToList( discreteFunction() );
        }
 
      private:
        template< class LocalDofVector >
        void read ( const std::vector< std::size_t > &blocks, LocalDofVector &localDofVector ) const
        {
          assert( localDofVector.size() == localBlockSize*blocks.size() );
          std::size_t index = 0;
          for( auto i : blocks )
          {
            const auto block = discreteFunction().block( i );
            for( std::size_t j = 0; j < localBlockSize; ++j )
              localDofVector[ index++ ] = (*block)[ j ];
          }
          assert( index == localDofVector.size() );
        }
 
        template< class LocalDofVector >
        void write ( const std::vector< std::size_t > &blocks, const LocalDofVector &localDofVector )
        {
          assert( localDofVector.size() == localBlockSize*blocks.size() );
          std::size_t index = 0;
          for( auto i : blocks )
          {
            auto block = discreteFunction().block( i );
            for( std::size_t j = 0; j < localBlockSize; ++j )
              (*block)[ j ] = localDofVector[ index++ ];
          }
          assert( index == localDofVector.size() );
        }
 
        DiscreteFunction &discreteFunction () { return discreteFunction_.get(); }
 
        const DiscreteFunction &discreteFunction () const { return discreteFunction_.get(); }
 
        const DiscreteFunctionSpaceType &space () const { return discreteFunction().space(); }
        LocalInterpolationType& interpolation ()
        {
          if( ! interpolation_ )
            interpolation_.reset( new LocalInterpolationType( space() ) );
          return *interpolation_;
        }
 
 
        std::reference_wrapper< DiscreteFunction > discreteFunction_;
        std::shared_ptr< LocalInterpolationType > interpolation_;
      };
 
    } // namespace hpDG
 
    // forward types to Fem namespace for convenience
    using hpDG::DefaultDataProjection;
 
  } // namespace Fem
 
} // namespace Dune
 
#endif // #ifndef DUNE_FEM_HPDG_SPACE_COMMON_DATAPROJECTION_DEFAULT_HH