DifferenceTransferStrategy.h

// Copyright (C) 2015 Technische Universitaet Muenchen
// This file is part of the Mamico project. For conditions of distribution
// and use, please see the copyright notice in Mamico's main folder, or at
// www5.in.tum.de/mamico
#ifndef _MOLECULARDYNAMICS_COUPLING_TRANSFERSTRATEGIES_DIFFERENCETRANSFERSTRATEGY_H_
#define _MOLECULARDYNAMICS_COUPLING_TRANSFERSTRATEGIES_DIFFERENCETRANSFERSTRATEGY_H_
 
#include "coupling/cell-mappings/ComputeMassMapping.h"
#include "coupling/cell-mappings/ComputeMomentumMapping.h"
#include "coupling/transferstrategies/TransferStrategy.h"
#include "tarch/la/Vector.h"
 
namespace coupling {
namespace transferstrategies {
template <class LinkedCell, unsigned int dim> class DifferenceTransferStrategy;
}
} // namespace coupling

template <class LinkedCell, unsigned int dim>
class coupling::transferstrategies::DifferenceTransferStrategy : public coupling::transferstrategies::TransferStrategy<LinkedCell, dim> {
public:
  DifferenceTransferStrategy(coupling::interface::MDSolverInterface<LinkedCell, dim>* const mdSolverInterface, unsigned int numberMDsteps)
      : coupling::transferstrategies::TransferStrategy<LinkedCell, dim>(mdSolverInterface), _numberMDsteps(numberMDsteps), _zero(0.0),
        _massMapping(mdSolverInterface), _momentumMapping(mdSolverInterface) {}

  virtual ~DifferenceTransferStrategy() {}

  void processInnerCouplingCellBeforeReceivingMacroscopicSolverData(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell,
                                                                    I02 index) override {
    // reset quantities
    cell.setMicroscopicMass(0.0);
    cell.setMicroscopicMomentum(_zero);
  }

  void processOuterCouplingCellBeforeReceivingMacroscopicSolverData(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell,
                                                                    I02 index) override {
    // reset quantities
    cell.setMicroscopicMass(0.0);
    cell.setMicroscopicMomentum(_zero);
  }

  void processInnerCouplingCellAfterReceivingMacroscopicSolverData(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell,
                                                                   I02 index) override {
    // compute difference between macroscopic and microscopic mass and momentum
    // values; this value is set in the microscopic data buffer of the
    // coupling cell.
    const double diffMass = cell.getMicroscopicMass() - cell.getMacroscopicMass();
    const tarch::la::Vector<dim, double> diffMomentum = cell.getMicroscopicMomentum() - cell.getMacroscopicMomentum();
    cell.setMicroscopicMass(diffMass);
    cell.setMicroscopicMomentum(diffMomentum);
    // reset coupling cell buffers
    cell.setMacroscopicMass(0.0);
    cell.setMacroscopicMomentum(_zero);
  }

  void processInnerCouplingCellBeforeSendingMDSolverData(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell, I02 index) override {
    // average quantities
    const double mass = cell.getMacroscopicMass() / ((double)_numberMDsteps);
    const tarch::la::Vector<dim, double> momentum = cell.getMacroscopicMomentum() * (1.0 / ((double)_numberMDsteps));
    cell.setMacroscopicMass(mass);
    cell.setMacroscopicMomentum(momentum);
  }

  void processInnerCouplingCellAfterMDTimestep(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell, I02 index) override {
    cell.iterateConstCells(_massMapping);
    const double mass = _massMapping.getMass();
    cell.iterateConstCells(_momentumMapping);
    const tarch::la::Vector<dim, double> momentum = _momentumMapping.getMomentum();
    cell.addMacroscopicMass(mass);
    cell.addMacroscopicMomentum(momentum);
  }
 
private:
  const unsigned int _numberMDsteps;
  const tarch::la::Vector<dim, double> _zero;
  coupling::cellmappings::ComputeMassMapping<LinkedCell, dim> _massMapping;
  coupling::cellmappings::ComputeMomentumMapping<LinkedCell, dim> _momentumMapping;
};
#endif // _MOLECULARDYNAMICS_COUPLING_TRANSFERSTRATEGIES_DIFFERENCETRANSFERSTRATEGY_H_