SetMomentumMapping.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_CELLMAPPINGS_SETMOMENTUMMAPPING_H_
#define _MOLECULARDYNAMICS_COUPLING_CELLMAPPINGS_SETMOMENTUMMAPPING_H_
 
#include "coupling/interface/MDSolverInterface.h"
#include "coupling/interface/Molecule.h"
#include <iostream>
 
namespace coupling {
namespace cellmappings {
template <class LinkedCell, unsigned int dim> class SetMomentumMapping;
}
} // namespace coupling

template <class LinkedCell, unsigned int dim> class coupling::cellmappings::SetMomentumMapping {
public:
  SetMomentumMapping(const tarch::la::Vector<dim, double>& oldMomentum, const tarch::la::Vector<dim, double>& newMomentum, const unsigned int& numberParticles,
                     coupling::interface::MDSolverInterface<LinkedCell, dim>* const mdSolverInterface)
      : _mdSolverInterface(mdSolverInterface), _oldVelocity(getVelocity(numberParticles, oldMomentum)),
        _newVelocity(getVelocity(numberParticles, newMomentum)) {}

  ~SetMomentumMapping() {}

  void beginCellIteration() {}

  void endCellIteration() {}

  void handleCell(LinkedCell& cell) {
    coupling::interface::MoleculeIterator<LinkedCell, dim>* it = _mdSolverInterface->getMoleculeIterator(cell);
    it->begin();
    while (it->continueIteration()) {
      coupling::interface::Molecule<dim>& wrapper(it->get());
      tarch::la::Vector<dim, double> velocity = wrapper.getVelocity();
      velocity = velocity - _oldVelocity + _newVelocity;
      wrapper.setVelocity(velocity);
 
      it->next();
    }
    delete it;
  }
 
private:
  tarch::la::Vector<dim, double> getVelocity(const unsigned int& numberParticles, const tarch::la::Vector<dim, double>& momentum) const {
    if (numberParticles != 0) {
      return (1.0 / (numberParticles * _mdSolverInterface->getMoleculeMass())) * momentum;
    } else {
      return tarch::la::Vector<dim, double>(0.0);
    }
  }
 
  coupling::interface::MDSolverInterface<LinkedCell, dim>* const _mdSolverInterface;
  tarch::la::Vector<dim, double> _oldVelocity;
  tarch::la::Vector<dim, double> _newVelocity;
};
#endif // _MOLECULARDYNAMICS_COUPLING_CELLMAPPINGS_SETMOMENTUMMAPPING_H_