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 _COUPLING_CELLMAPPINGS_PERTURBATEVELOCITYMAPPING_H_
       6             : #define _COUPLING_CELLMAPPINGS_PERTURBATEVELOCITYMAPPING_H_
       7             : 
       8             : #include "coupling/interface/MDSolverInterface.h"
       9             : #include "tarch/utils/RandomNumberService.h"
      10             : 
      11             : namespace coupling {
      12             : namespace cellmappings {
      13             : template <class LinkedCell, unsigned int dim> class PerturbateVelocityMapping;
      14             : }
      15             : } // namespace coupling
      16             : 
      17             : /** This class is used to superimpose a random perturbation to the mean velocity
      18             :  *in all directions. It is use for Dynamic MD cases to launch new MD instances
      19             :  *with independent molecular values (velocities)
      20             :  *      @brief This class is used to superimpose a random perturbation to the
      21             :  *mean velocity in all directions.
      22             :  *      @tparam LinkedCell cell type
      23             :  *      @tparam dim Number of dimensions; it can be 1, 2 or 3
      24             :  *  @author Niklas Wittmer
      25             :  */
      26             : template <class LinkedCell, unsigned int dim> class coupling::cellmappings::PerturbateVelocityMapping {
      27             : public:
      28             :   /** Constructor
      29             :    *    @param mdSolverInterface
      30             :    *    @param velocity
      31             :    *    @param temperature
      32             :    */
      33           0 :   PerturbateVelocityMapping(coupling::interface::MDSolverInterface<LinkedCell, dim>* const mdSolverInterface, const tarch::la::Vector<dim, double>& velocity,
      34             :                             const double& temperature)
      35           0 :       : _mdSolverInterface(mdSolverInterface), _molecularMass(mdSolverInterface->getMoleculeMass()), _kB(mdSolverInterface->getKB()), _temperature(temperature),
      36           0 :         _velocity(velocity), _sigma(_mdSolverInterface->getMoleculeSigma()) {}
      37             : 
      38             :   /** Destructor */
      39           0 :   ~PerturbateVelocityMapping() {}
      40             : 
      41             :   /** empty function
      42             :    */
      43             :   void beginCellIteration() {}
      44             :   /** empty function
      45             :    */
      46             :   void endCellIteration() {}
      47             : 
      48             :   /** superimposes a random perturbation to the mean velocity in all directions
      49             :    *    @param cell
      50             :    */
      51           0 :   void handleCell(LinkedCell& cell) {
      52             : 
      53           0 :     double stdDeviation = std::sqrt(dim * _kB * _temperature / _molecularMass);
      54             : 
      55           0 :     tarch::la::Vector<dim, double> randomNumbers(0.0);
      56             : 
      57           0 :     coupling::interface::MoleculeIterator<LinkedCell, dim>* molecule = _mdSolverInterface->getMoleculeIterator(cell);
      58           0 :     molecule->begin();
      59           0 :     while (molecule->continueIteration()) {
      60           0 :       coupling::interface::Molecule<dim>& wrapper(molecule->get());
      61           0 :       randomNumbers[0] = tarch::utils::RandomNumberService::getInstance().getGaussianRandomNumber();
      62           0 :       for (unsigned int d = 1; d < dim; ++d) {
      63           0 :         randomNumbers[d] = tarch::utils::RandomNumberService::getInstance().getGaussianRandomNumber();
      64             :       }
      65             : 
      66           0 :       tarch::la::Vector<dim, double> mVelocity = wrapper.getVelocity();
      67             :       if (dim == 3) {
      68           0 :         mVelocity[0] = _velocity[0] + stdDeviation * (randomNumbers[0] * std::sin(randomNumbers[1]) * std::cos(randomNumbers[2]));
      69           0 :         mVelocity[1] = _velocity[1] + stdDeviation * (randomNumbers[0] * std::sin(randomNumbers[1]) * std::sin(randomNumbers[2]));
      70           0 :         mVelocity[2] = _velocity[2] + stdDeviation * (randomNumbers[0] * std::cos(randomNumbers[1]));
      71             :       } else if (dim == 1) {
      72             :         mVelocity = _velocity + stdDeviation * randomNumbers;
      73             :       } else if (dim == 2) {
      74             :         mVelocity[0] = _velocity[0] + stdDeviation * (randomNumbers[0] * std::cos(randomNumbers[1]));
      75             :         mVelocity[1] = _velocity[1] + stdDeviation * (randomNumbers[0] * std::sin(randomNumbers[1]));
      76             :       }
      77           0 :       wrapper.setVelocity(mVelocity);
      78             : 
      79           0 :       molecule->next();
      80             :     }
      81           0 :     delete molecule;
      82           0 :   }
      83             : 
      84             : private:
      85             :   coupling::interface::MDSolverInterface<LinkedCell, dim>* const _mdSolverInterface;
      86             :   const double _molecularMass;
      87             :   const double _kB;
      88             :   const double _temperature;
      89             :   const tarch::la::Vector<dim, double> _velocity;
      90             :   const double _sigma;
      91             : };
      92             : 
      93             : #endif //_COUPLING_CELLMAPPINGS_VARYCHECKPOINTMAPPING_H_