Line data    Source code

       1              : // Copyright (C) 2015 Technische Universitaet Muenchen
       2              : // This file is part of the Mamico project. For conditions of distribution
       3              : // and use, please see the copyright notice in Mamico's main folder, or at
       4              : // www5.in.tum.de/mamico
       5              : #ifndef _MOLECULARDYNAMICS_COUPLING_ADDITIVEMOMENTUMINSERTION_H_
       6              : #define _MOLECULARDYNAMICS_COUPLING_ADDITIVEMOMENTUMINSERTION_H_
       7              : 
       8              : #include "coupling/MomentumInsertion.h"
       9              : #include "coupling/cell-mappings/ComputeMassMapping.h"
      10              : #include "coupling/cell-mappings/SetMomentumMapping.h"
      11              : #include "coupling/datastructures/CouplingCell.h"
      12              : #include "tarch/la/Vector.h"
      13              : 
      14              : /** @brief everything necessary for coupling operations, is defined in here */
      15              : namespace coupling {
      16              : template <class LinkedCell, unsigned int dim> class AdditiveMomentumInsertion;
      17              : }
      18              : 
      19              : /** This class allows to add momentum to molecules. In each MD timestep, it
      20              :  * takes a respective fraction from the momentum buffer of a coupling cell
      21              :  * and adds this momentum to the molecules of the coupling cell.
      22              :  *  @brief used to manipulate the momentum/velocity of the molecules contained
      23              :  * in a coupling cell.
      24              :  *  @tparam LinkedCell the LinkedCell class is given by the implementation of
      25              :  * linked cells in the molecular dynamics simulation
      26              :  *  @tparam dim the integer dim refers to the spacial dimension of the
      27              :  * simulation, can be 1, 2, or 3
      28              :  *  @author Philipp Neumann
      29              :  */
      30              : template <class LinkedCell, unsigned int dim> class coupling::AdditiveMomentumInsertion : public coupling::MomentumInsertion<LinkedCell, dim> {
      31              : public:
      32              :   /** @brief A simple constructor
      33              :    *   @param mdSolverInterface The interface of the molecular dynamics solver
      34              :    * in application
      35              :    *   @param numberMDTimestepsPerCouplingCycle The number of molecular dynamics
      36              :    * timesteps within one coupling cycle */
      37            0 :   AdditiveMomentumInsertion(coupling::interface::MDSolverInterface<LinkedCell, dim>* const mdSolverInterface, unsigned int numberMDTimestepsPerCouplingCycle)
      38            0 :       : coupling::MomentumInsertion<LinkedCell, dim>(mdSolverInterface), _numberMDTimestepsPerCouplingCycle(numberMDTimestepsPerCouplingCycle) {}
      39              : 
      40              :   /** @brief A simple destructor*/
      41            0 :   ~AdditiveMomentumInsertion() {}
      42              : 
      43              :   /** returns 1 since momentum shall be inserted in every time step
      44              :    *  @brief returns the interval of time steps for momentum insertion
      45              :    *  @returns 1 */
      46            0 :   unsigned int getTimeIntervalPerMomentumInsertion() const override { return 1; }
      47              : 
      48              :   /** inserts the momentum of the coupling cell and distributes it over all
      49              :    * molecules. This method does not conserve the kinetic energy of the
      50              :    * respective coupling cell. To conserve the energy as well, see the
      51              :    * description of MomentumController on details how to do that.
      52              :    *  @brief inserts momentum to the cell
      53              :    *  @param cell coupling cell to insert momentum to
      54              :    *  @param idx coupling cell index of the cell */
      55            0 :   void insertMomentum(coupling::datastructures::CouplingCellWithLinkedCells<LinkedCell, dim>& cell, I02 idx) const override {
      56            0 :     const unsigned int timeIntervalMomentumInsertion = getTimeIntervalPerMomentumInsertion();
      57              :     // determine fraction of momentum that is to be inserted in this frame
      58            0 :     double fraction = 1.0 / ((_numberMDTimestepsPerCouplingCycle / timeIntervalMomentumInsertion) +
      59            0 :                              (_numberMDTimestepsPerCouplingCycle % timeIntervalMomentumInsertion != 0));
      60            0 :     tarch::la::Vector<dim, double> momentum(fraction * cell.getMicroscopicMomentum());
      61            0 :     tarch::la::Vector<dim, double> zeroMomentum(0.0);
      62              : 
      63              :     // if there is some momentum to be transferred, do so
      64            0 :     if (tarch::la::dot(momentum, momentum) != 0.0) {
      65            0 :       coupling::cellmappings::ComputeMassMapping<LinkedCell, dim> computeMassMapping(coupling::MomentumInsertion<LinkedCell, dim>::_mdSolverInterface);
      66            0 :       cell.iterateConstCells(computeMassMapping);
      67              :       unsigned int numberParticles = computeMassMapping.getNumberOfParticles();
      68            0 :       coupling::cellmappings::SetMomentumMapping<LinkedCell, dim> setMomentumMapping(zeroMomentum, momentum, numberParticles,
      69            0 :                                                                                      coupling::MomentumInsertion<LinkedCell, dim>::_mdSolverInterface);
      70            0 :       cell.iterateCells(setMomentumMapping);
      71            0 :     }
      72            0 :   }
      73              : 
      74            0 :   void setInnerImposition(bool enable) override {
      75            0 :     throw std::runtime_error(std::string("coupling::AdditiveMomentumInsertion::setInnerImposition not implemented"));
      76              :   }
      77              : 
      78              : private:
      79              :   const unsigned int _numberMDTimestepsPerCouplingCycle; ///< The number of molecular dynamics
      80              :                                                          ///< timesteps within one coupling
      81              :                                                          ///< cycle */
      82              : };
      83              : #endif // _MOLECULARDYNAMICS_COUPLING_ADDITIVEMOMENTUMINSERTION_H_