ReferenceVariableStochasticDynamics.h

/* Portions copyright (c) 2006-2012 Stanford University and Simbios.
 * Contributors: Pande Group
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#ifndef __ReferenceVariableStochasticDynamics_H__
#define __ReferenceVariableStochasticDynamics_H__

#include "ReferenceDynamics.h"

namespace OpenMM {

class ReferenceVariableStochasticDynamics : public ReferenceDynamics {

   private:

      std::vector<OpenMM::RealVec> xPrime;
      std::vector<RealOpenMM> inverseMasses;
      RealOpenMM _tau, _accuracy;

   public:

      /**---------------------------------------------------------------------------------------

         Constructor

         @param numberOfAtoms  number of atoms
         @param tau            viscosity
         @param temperature    temperature
         @param accuracy       required accuracy

         --------------------------------------------------------------------------------------- */

       ReferenceVariableStochasticDynamics( int numberOfAtoms, RealOpenMM tau, RealOpenMM temperature, RealOpenMM accuracy );

      /**---------------------------------------------------------------------------------------

         Destructor

         --------------------------------------------------------------------------------------- */

       ~ReferenceVariableStochasticDynamics( );

      /**---------------------------------------------------------------------------------------

         Get tau

         @return tau

         --------------------------------------------------------------------------------------- */

      RealOpenMM getTau( void ) const;
      
      /**---------------------------------------------------------------------------------------

         Get the required accuracy

         @return accuracy

         --------------------------------------------------------------------------------------- */

      RealOpenMM getAccuracy( void ) const;

      /**---------------------------------------------------------------------------------------

         Set the required accuracy

         --------------------------------------------------------------------------------------- */

      void setAccuracy( RealOpenMM accuracy );

      /**---------------------------------------------------------------------------------------

         Update

         @param system              the System to be integrated
         @param atomCoordinates     atom coordinates
         @param velocities          velocities
         @param forces              forces
         @param masses              atom masses
         @param maxStepSize         maximum time step
         @param tolerance           the constraint tolerance

         --------------------------------------------------------------------------------------- */

      void update(const OpenMM::System& system, std::vector<OpenMM::RealVec>& atomCoordinates,
                  std::vector<OpenMM::RealVec>& velocities, std::vector<OpenMM::RealVec>& forces, std::vector<RealOpenMM>& masses, RealOpenMM maxStepSize, RealOpenMM tolerance);

      /**---------------------------------------------------------------------------------------

         First update; based on code in update.c do_update_sd() Gromacs 3.1.4

         @param numberOfAtoms       number of atoms
         @param atomCoordinates     atom coordinates
         @param velocities          velocities
         @param forces              forces
         @param masses              atom masses
         @param inverseMasses       inverse atom masses
         @param xPrime              xPrime
         @param maxStepSize         maximum time step

         --------------------------------------------------------------------------------------- */

      void updatePart1( int numberOfAtoms, std::vector<OpenMM::RealVec>& atomCoordinates, std::vector<OpenMM::RealVec>& velocities,
                       std::vector<OpenMM::RealVec>& forces, std::vector<RealOpenMM>& masses, std::vector<RealOpenMM>& inverseMasses,
                       std::vector<OpenMM::RealVec>& xPrime, RealOpenMM maxStepSize );

      /**---------------------------------------------------------------------------------------

         Second update

         @param numberOfAtoms       number of atoms
         @param atomCoordinates     atom coordinates
         @param velocities          velocities
         @param forces              forces
         @param masses              atom masses

         --------------------------------------------------------------------------------------- */

      void updatePart2( int numberOfAtoms, std::vector<OpenMM::RealVec>& atomCoordinates, std::vector<OpenMM::RealVec>& velocities,
                       std::vector<OpenMM::RealVec>& forces, std::vector<RealOpenMM>& inverseMasses,
                       std::vector<OpenMM::RealVec>& xPrime );
      
};

} // namespace OpenMM

#endif // __ReferenceVariableStochasticDynamics_H__