Rattle.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 CONSTRAINTS_RATTLE_HPP
#define CONSTRAINTS_RATTLE_HPP
 
#include "brains/SimInfo.hpp"
#include "constraints/ConstraintPair.hpp"
#include "io/ConstraintWriter.hpp"
 
namespace OpenMD {
 
  /**
   * @class Rattle Rattle.hpp "constraints/Rattle.hpp"
   * Velocity Verlet Constraint Algorithm
   */
  class Rattle {
  public:
    enum ConsStatus {
      consFail    = -1,  // Constraint Fail
      consSuccess = 0,   // constrain the pair by moving two elements
      consAlready = 1    // current pair is already constrained, do not need to
                         // move the elements
    };
 
    Rattle(SimInfo* info);
    ~Rattle();
    void constraintA();
    void constraintB();
 
    int getMaxConsIteration() { return maxConsIteration_; }
    void setMaxConsIteration(int iteration) { maxConsIteration_ = iteration; }
 
    RealType getConsTolerance() { return consTolerance_; }
    void setConsTolerance(RealType tolerance) { consTolerance_ = tolerance; }
 
  private:
    typedef int (Rattle::*ConstraintPairFuncPtr)(ConstraintPair*);
    void doConstraint(ConstraintPairFuncPtr func);
    int constraintPairA(ConstraintPair* consPair);
    int constraintPairB(ConstraintPair* consPair);
 
    SimInfo* info_ {nullptr};
    int maxConsIteration_;
    RealType consTolerance_;
    RealType dt_;
    Snapshot* currentSnapshot_ {nullptr};
    bool doRattle_ {false};
    std::string constraintOutputFile_;
    ConstraintWriter* constraintWriter_ {nullptr};
    RealType constraintTime_;
    RealType currConstraintTime_;
  };
}  // namespace OpenMD
 
#endif