LDForceModifier.hpp

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 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the appropriate papers when you publish your
 * work.  Good starting points are:
 *
 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
 * [2] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
 * [4] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 * [5] Kuang & Gezelter, Mol. Phys., 110, 691-701 (2012).
 * [6] Lamichhane, Gezelter & Newman, J. Chem. Phys. 141, 134109 (2014).
 * [7] Lamichhane, Newman & Gezelter, J. Chem. Phys. 141, 134110 (2014).
 * [8] Bhattarai, Newman & Gezelter, Phys. Rev. B 99, 094106 (2019).
 */
 
#ifndef INTEGRATOR_LDFORCEMODIFIER_HPP
#define INTEGRATOR_LDFORCEMODIFIER_HPP
 
#include <map>
#include <memory>
#include <random>
#include <string>
#include <vector>
 
#include "brains/ForceModifier.hpp"
#include "brains/Velocitizer.hpp"
#include "hydrodynamics/Shape.hpp"
#include "primitives/Molecule.hpp"
#include "utils/RandNumGen.hpp"
 
namespace OpenMD {
 
  struct SDShape {
    StuntDouble* sd;
    Shape* shape;
  };
 
  struct MomentData {
    Vector3d rcr;   /**< Distance between CoM and Center of Resistance */
    Mat3x3d Icr;    /**< Moment of Inertia at Center of Resistance */
    Mat3x3d IcrInv; /**< Icr^{-1}  */
  };
 
  /**
   * @class LDForceModifier
   * Force modifier for Langevin Dynamics applying friction and random
   * forces as well as torques.
   */
  class LDForceModifier : public ForceModifier {
  public:
    LDForceModifier(SimInfo* info);
 
    void modifyForces() override;
    int getMaxIterationNumber() { return maxIterNum_; }
    void setMaxIterationNumber(int maxIter) { maxIterNum_ = maxIter; }
    RealType getForceTolerance() { return forceTolerance_; }
    void setForceTolerance(RealType tol) { forceTolerance_ = tol; }
 
  private:
    MomentData* getMomentData(StuntDouble* sd);
    void genRandomForceAndTorque(Vector3d& force, Vector3d& torque,
                                 unsigned int index);
 
    std::map<std::string, HydroProp*> hydroPropMap_;
    std::vector<HydroProp*> hydroProps_;
 
    std::map<std::string, MomentData*> momentsMap_;
    std::vector<MomentData*> moments_;
 
    // convergence parameters:
    int maxIterNum_;
    RealType forceTolerance_;
    RealType dt2_;
 
    // random number generation:
    Utils::RandNumGenPtr randNumGen_;
    std::normal_distribution<RealType> forceDistribution_;
 
    RealType langevinBufferRadius_;
    RealType frozenBufferRadius_;
    bool sphericalBoundaryConditions_;
    Globals* simParams_;
    std::unique_ptr<Velocitizer> veloMunge_ {nullptr};
  };
}  // namespace OpenMD
 
#endif  // INTEGRATOR_LDFORCEMODIFIER_HPP