function/common/localcontribution.hh

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#ifndef DUNE_FEM_FUNCTION_COMMON_LOCALCONTRIBUTION_HH
#define DUNE_FEM_FUNCTION_COMMON_LOCALCONTRIBUTION_HH
 
#include <algorithm>
#include <type_traits>
#include <utility>
#include <vector>
 
#include <dune/common/densevector.hh>
#include <dune/common/ftraits.hh>
 
#include <dune/fem/common/hybrid.hh>
#include <dune/fem/common/localcontribution.hh>
#include <dune/fem/space/common/commoperations.hh>
#include <dune/fem/function/localfunction/temporary.hh>
 
namespace Dune
{
 
  namespace Fem
  {
 
    // External Forward Declarations
    // -----------------------------
 
    template< class >
    struct DiscreteFunctionTraits;
 
    class IsDiscreteFunction;
 
 
 
    namespace Assembly
    {
 
      namespace Global
      {
 
        // AddBase
        // -------
 
        template< class DiscreteFunction >
        struct AddBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
        {
          typedef typename DiscreteFunction::DofType DofType;
 
          static void begin ( DiscreteFunction &df )
          {
            typedef typename DiscreteFunction::DiscreteFunctionSpaceType::LocalBlockIndices LocalBlockIndices;
 
            // clear auxiliary DoFs
            auto &dofVector = df.dofVector();
            for( const auto &auxiliaryDof : df.space().auxiliaryDofs() )
              Hybrid::forEach( LocalBlockIndices(), [ &dofVector, &auxiliaryDof ] ( auto &&j ) { dofVector[ auxiliaryDof ][ j ] = DofType( 0 ); } );
          }
 
          static void end ( DiscreteFunction &df, const bool communicate )
          {
            if ( communicate )
            {
              df.space().communicate( df, DFCommunicationOperation::Add() );
            }
          }
        };
 
 
 
        // SetBase
        // -------
 
        template< class DiscreteFunction >
        struct SetBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
        {
          static void begin ( DiscreteFunction &df ) {}
          static void end ( DiscreteFunction &df, const bool communicate )
          {
            if ( communicate )
            {
              df.space().communicate( df, DFCommunicationOperation::Copy() );
            }
          }
        };
 
      } // namespace Global
 
 
 
      // AddBase
      // -------
 
      template< class DiscreteFunction >
      struct AddBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
      {
        typedef typename DiscreteFunction::DofType DofType;
 
        typedef Global::Add< DiscreteFunction > GlobalOperationType;
 
        template< class Entity, class LocalDofVector >
        void begin ( const Entity &entity, const DiscreteFunction &df, LocalDofVector &localDofVector ) const
        {
          std::fill( localDofVector.begin(), localDofVector.end(), DofType( 0 ) );
        }
 
        template< class Entity, class LocalDofVector >
        void end ( const Entity &entity, LocalDofVector &localDofVector, DiscreteFunction &df ) const
        {
          df.addLocalDofs( entity, localDofVector );
        }
      };
 
 
 
      // AddScaledBase
      // -------------
 
      template< class DiscreteFunction >
      struct AddScaledBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
        : public AddBase< DiscreteFunction >
      {
        AddScaledBase ( typename DiscreteFunction::DofType factor ) : factor_( std::move( factor ) ) {}
 
        template< class Entity, class LocalDofVector >
        void end ( const Entity &entity, LocalDofVector &localDofVector, DiscreteFunction &df ) const
        {
          df.addScaledLocalDofs( entity, factor_, localDofVector );
        }
 
      private:
        typename DiscreteFunction::DofType factor_;
      };
 
 
      namespace detail
      {
 
        template< class DiscreteFunction, const bool getAndSet >
        struct SetAndSelectDFImpl
        {
          typedef typename DiscreteFunction::DofType DofType;
 
          typedef Global::Set< DiscreteFunction > GlobalOperationType;
 
          template< class Entity, class LocalDofVector >
          void begin ( const Entity &entity, const DiscreteFunction &df, LocalDofVector &localDofVector ) const
          {
            if constexpr ( getAndSet )
            {
              // obtain local dofs
              df.getLocalDofs ( entity, localDofVector );
            }
            else
            {
              // reset all dofs
              std::fill( localDofVector.begin(), localDofVector.end(), DofType( 0 ) );
            }
          }
 
          template< class Entity, class LocalDofVector >
          void end ( const Entity &entity, LocalDofVector &localDofVector, DiscreteFunction &df ) const
          {
            df.setLocalDofs( entity, localDofVector );
          }
        };
      }
 
 
      // SetBase
      // -------
 
      template< class DiscreteFunction >
      struct SetBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
        : public detail::SetAndSelectDFImpl< DiscreteFunction, false >
      {};
 
      // SetSelectedBase
      // ---------------
 
      template< class DiscreteFunction >
      struct SetSelectedBase< DiscreteFunction, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
        : public detail::SetAndSelectDFImpl< DiscreteFunction, true >
      {};
 
    } // namespace Assembly
  }
 
  // consistency with Dune::DenseVector and DenseMatrix
  template< class DiscreteFunction, template< class > class AssemblyOperation >
  struct FieldTraits< Fem::LocalContribution< DiscreteFunction,  AssemblyOperation, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > > >
    : public FieldTraits< typename DiscreteFunction::DofType >
  {
  };
 
 
  namespace Fem
  {
 
    // LocalContribution for Discrete Functions
    // ----------------------------------------
 
    template< class DiscreteFunction, template< class > class AssemblyOperation >
    class LocalContribution< DiscreteFunction, AssemblyOperation, std::enable_if_t< std::is_base_of< Fem::IsDiscreteFunction, DiscreteFunction >::value > >
      : public TemporaryLocalFunction< typename DiscreteFunction::DiscreteFunctionSpaceType >
    {
      typedef typename DiscreteFunction::DiscreteFunctionSpaceType  DiscreteFunctionSpaceType;
      typedef LocalContribution< DiscreteFunction, AssemblyOperation >  ThisType;
      typedef TemporaryLocalFunction< DiscreteFunctionSpaceType >       BaseType;
 
    public:
      typedef DiscreteFunction DiscreteFunctionType;
      typedef AssemblyOperation< typename DiscreteFunctionTraits< DiscreteFunctionType >::DiscreteFunctionType > AssemblyOperationType;
 
      typedef typename DiscreteFunctionType::DiscreteFunctionSpaceType::BasisFunctionSetType BasisFunctionSetType;
      typedef typename DiscreteFunctionType::DofType DofType;
 
      typedef typename DiscreteFunctionType::RangeType RangeType;
      typedef typename RangeType::field_type RangeFieldType;
      typedef typename DiscreteFunctionType::JacobianRangeType JacobianRangeType;
 
      typedef typename BaseType :: LocalDofVectorType  LocalDofVectorType;
      typedef typename LocalDofVectorType::size_type SizeType;
 
      typedef typename BasisFunctionSetType::EntityType EntityType;
 
      using BaseType::entity;
      using BaseType::localDofVector;
      using BaseType::axpy;
 
      template< class... Args >
      explicit LocalContribution ( DiscreteFunctionType &discreteFunction, const bool communicate, Args &&... args )
        : BaseType( discreteFunction.space() ),
          discreteFunction_( discreteFunction ),
          assemblyOperation_( std::forward< Args >( args )... ),
          communicate_( communicate ),
          bound_( false )
      {
        discreteFunction.template beginAssemble< typename AssemblyOperationType::GlobalOperationType >();
      }
 
      template< class... Args >
      explicit LocalContribution ( DiscreteFunctionType &discreteFunction, Args &&... args )
        : LocalContribution( discreteFunction, /* communicate */ true, args... )
      {}
 
      LocalContribution ( const ThisType & ) = delete;
      LocalContribution ( ThisType && ) = delete;
 
      ~LocalContribution () { discreteFunction().template endAssemble< typename AssemblyOperationType::GlobalOperationType >( communicate_ ); }
 
      ThisType &operator= ( const ThisType & ) = delete;
      ThisType &operator= ( ThisType && ) = delete;
 
      const DiscreteFunctionType& discreteFunction () const { return discreteFunction_; }
      DiscreteFunctionType& discreteFunction () { return discreteFunction_; }
 
      void bind ( const EntityType &entity )
      {
        BaseType::bind( entity );
        bound_ = true;
        assemblyOperation_.begin( entity, discreteFunction(), localDofVector() );
      }
 
      void unbind ()
      {
        if (bound_)
        {
          // write back dofs to discrete function
          assemblyOperation_.end( entity(), localDofVector(), discreteFunction() );
          // unbind local contribution
          BaseType::unbind();
        }
      }
 
    protected:
      // LocalContribution is not a LocalFunction,
      // thus disable evaluate,jacobian and hessian methods
      using BaseType::evaluate;
      using BaseType::evaluateQuadrature;
      using BaseType::jacobian;
      using BaseType::hessian;
 
    protected:
      DiscreteFunctionType& discreteFunction_;
      AssemblyOperationType assemblyOperation_;
      const bool communicate_;
      bool bound_;
    };
 
  } // namespace Fem
 
} // namespace Dune
 
#endif // #ifndef DUNE_FEM_FUNCTION_COMMON_LOCALCONTRIBUTION_HH