ZconstraintForceModifier.hpp

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 * SUPPORT OPEN SCIENCE!  If you use OpenMD or its source code in your
 * research, please cite the following paper when you publish your work:
 *
 * [1] Drisko et al., J. Open Source Softw. 9, 7004 (2024).
 *
 * Good starting points for code and simulation methodology are:
 *
 * [2] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
 * [3] Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).
 * [4] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
 * [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
 * [6] Kuang & Gezelter, Mol. Phys., 110, 691-701 (2012).
 * [7] Lamichhane, Gezelter & Newman, J. Chem. Phys. 141, 134109 (2014).
 * [8] Bhattarai, Newman & Gezelter, Phys. Rev. B 99, 094106 (2019).
 * [9] Drisko & Gezelter, J. Chem. Theory Comput. 20, 4986-4997 (2024).
 */
 
#ifndef CONSTRAINTS_ZCONSTRAINTFORCEMODIFIER_HPP
#define CONSTRAINTS_ZCONSTRAINTFORCEMODIFIER_HPP
 
#include <list>
#include <string>
#include <vector>
 
#include "brains/ForceModifier.hpp"
#include "constraints/ZconsStruct.hpp"
#include "io/ZConsWriter.hpp"
 
namespace OpenMD {
 
  class ZConstraintForceModifier : public ForceModifier {
  public:
    ZConstraintForceModifier(SimInfo* info);
    ~ZConstraintForceModifier();
 
    void modifyForces() override;
 
    RealType getZConsTime() { return zconsTime_; }
    std::string getZConsOutput() { return zconsOutput_; }
 
  private:
    RealType getZTargetPos(int index);
    void update();
    void calcTotalMassMovingZMols();
    bool isZMol(Molecule* mol);
    void updateZPos();
    bool checkZConsState();
    void zeroVelocity();
    bool haveFixedZMols();
    void doZconstraintForce();
    RealType getZFOfFixedZMols(Molecule* mol, StuntDouble* sd,
                               RealType totalForce);
    RealType getZFOfMovingMols(Molecule* mol, RealType totalForce);
    bool haveMovingZMols();
    void doHarmonic();
    RealType getHFOfFixedZMols(Molecule* mol, StuntDouble* sd,
                               RealType totalForce);
    RealType getHFOfUnconsMols(Molecule* mol, RealType totalForce);
 
    // void updateCantPos();
 
    std::list<ZconstraintMol> movingZMols_; /**< moving zconstraint molecules */
    std::list<ZconstraintMol> fixedZMols_;  /**< fixed zconstraint molecules */
    std::vector<Molecule*> unzconsMols_;    /**< free molecules */
 
    RealType zconsTime_;
    std::string zconsOutput_;
    RealType zconsTol_;
    bool usingSMD_;
    RealType zconsFixingTime_;
    RealType zconsGap_;
    bool usingZconsGap_;
    RealType dt_;
 
    const static int whichDirection = 2;
 
    std::map<int, ZconstraintParam> allZMolIndices_;
 
    Snapshot* currSnapshot_;
    RealType currZconsTime_;
 
    RealType totMassMovingZMols_;
    RealType totMassUnconsMols_; /**< mass of unconstrained molecules
                                     in the system (never changes) */
 
    ZConsWriter* fzOut;
    const RealType infiniteTime;
  };
}  // namespace OpenMD
 
#endif  // CONSTRAINTS_ZCONSTRAINTFORCEMODIFIER_HPP