preconditionfunctionwrapper.hh

#ifndef DUNE_FEM_SOLVER_PRECONDITIONFUNCTIONWRAPPER_HH
#define DUNE_FEM_SOLVER_PRECONDITIONFUNCTIONWRAPPER_HH
 
#include <functional>
 
#include <dune/fem/operator/common/operator.hh>
 
namespace Dune
{
  namespace Fem
  {
    template <class DomainFunction, class RangeFunction = DomainFunction>
    class PreconditionerFunctionWrapper
      : public virtual Operator< DomainFunction, RangeFunction >
    {
    public:
      typedef DomainFunction  DomainFunctionType;
      typedef RangeFunction   RangeFunctionType;
 
      typedef std::reference_wrapper< const DomainFunctionType >  ConstDomainDFType;
      typedef std::reference_wrapper< RangeFunctionType >         RangeDFType;
      typedef std::function< void( ConstDomainDFType& , RangeDFType& ) > PreconditionerFunctionType;
 
    protected:
      const PreconditionerFunctionType& preconditioner_; // function given from Python side
    public:
      PreconditionerFunctionWrapper( const PreconditionerFunctionType& pre )
        : preconditioner_( pre ) {}
 
      virtual void operator() ( const DomainFunctionType &u, RangeFunctionType &v ) const final override
      {
        // convert to reference_wrapper to avoid copying
        ConstDomainDFType uR( u );
        RangeDFType vR( v );
 
        // callback to python applying preconditioner
        preconditioner_( uR, vR );
      }
    };
 
  } // end namespace Fem
 
} // end namespace Dune
#endif