/* Portions copyright (c) 2006 Stanford University and Simbios.
 * Contributors: Pande Group
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject
 * to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS, CONTRIBUTORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#ifndef __ReferenceStochasticDynamics_H__
#define __ReferenceStochasticDynamics_H__

#include "ReferenceDynamics.h"

// ---------------------------------------------------------------------------------------

class ReferenceStochasticDynamics : public ReferenceDynamics {

   private:

      enum TwoDArrayIndicies { xPrime2D, Max2DArrays };
      enum OneDArrayIndicies { InverseMasses, Max1DArrays };

      RealOpenMM _tau;
      
   public:

      /**---------------------------------------------------------------------------------------
      
         Constructor

         @param numberOfAtoms  number of atoms
         @param deltaT         delta t for dynamics
         @param tau            viscosity
         @param temperature    temperature
      
         --------------------------------------------------------------------------------------- */

       ReferenceStochasticDynamics( int numberOfAtoms, RealOpenMM deltaT, RealOpenMM tau, RealOpenMM temperature );

      /**---------------------------------------------------------------------------------------
      
         Destructor
      
         --------------------------------------------------------------------------------------- */

       ~ReferenceStochasticDynamics( );

      /**---------------------------------------------------------------------------------------
      
         Get tau
      
         @return tau
      
         --------------------------------------------------------------------------------------- */
      
      RealOpenMM getTau( void ) const;
      
      /**---------------------------------------------------------------------------------------
      
         Update
      
         @param numberOfAtoms       number of atoms
         @param atomCoordinates     atom coordinates
         @param velocities          velocities
         @param forces              forces
         @param masses              atom masses
      
         @return ReferenceDynamics::DefaultReturn
      
         --------------------------------------------------------------------------------------- */
     
      int update( int numberOfAtoms, RealOpenMM** atomCoordinates,
                  RealOpenMM** velocities, RealOpenMM** forces, RealOpenMM* masses );
     
      /**---------------------------------------------------------------------------------------
      
         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 inverseMasses       inverse atom masses
         @param xPrime              xPrime
      
         @return ReferenceDynamics::DefaultReturn
      
         --------------------------------------------------------------------------------------- */
      
      int updatePart1( int numberOfAtoms, RealOpenMM** atomCoordinates, RealOpenMM** velocities,
                       RealOpenMM** forces, RealOpenMM* inverseMasses, RealOpenMM** xPrime );
      
      /**---------------------------------------------------------------------------------------
      
         Second update
      
         @param numberOfAtoms       number of atoms
         @param atomCoordinates     atom coordinates
         @param velocities          velocities
         @param forces              forces
         @param masses              atom masses
      
         @return ReferenceDynamics::DefaultReturn
      
         --------------------------------------------------------------------------------------- */
      
      int updatePart2( int numberOfAtoms, RealOpenMM** atomCoordinates, RealOpenMM** velocities,
                       RealOpenMM** forces, RealOpenMM* inverseMasses, RealOpenMM** xPrime );
      
};

// ---------------------------------------------------------------------------------------

#endif // __ReferenceStochasticDynamics_H__