/*   []----------------------------------------[]
      |                PointPair.h             |
     []----------------------------------------[]
      |                                        |
      |   AUTHOR:    MFSomers 2005.            |
      |   USE:       Point pair interaction    |
      |               definitions...           |      
      |                                        |
     []----------------------------------------[]
*/

// Copyright (C) 2005 M.F. Somers, Theoretical Chemistry Department, Leiden University
//
// This is free software; you can redistribute it and/or modify it under the terms of
// the GNU Lesser General Public License as published by the Free Software Foundation.
//
// http://www.gnu.org/licenses/lgpl.txt

#if !defined(__POINTPAIRINTERACTION_INCLUDED__)

#define __POINTPAIRINTERACTION_INCLUDED__

#include <vector>

#include "Global.h"
#include "Vector.h"
#include "Constants.h"
#include "ClassicalDynamics.h"
       
/* ----------------------------------------------------------------------- */       
/* Definition of a point pair interaction */

class   PointPairInteraction;
typedef PointPairInteraction *PointPairInteractionPointer;

class PointPairInteraction : public Interaction
                             {
		              public:
			     
			      inline PointPairInteraction( unsigned int TheId = GET_NEW_ID, Vector *UsePeriodicBox = NULL ) : Interaction( TheId, UsePeriodicBox )
			      {
			       Type = AGeneralPointPairInteraction;
			      };

			      inline PointPairInteraction( PointPairInteraction& I ) : Interaction( I )
			      {
			      }
			      
			      virtual PointPairInteractionPointer Clone()
		              {
		               return( new PointPairInteraction( (*this) ) );
		              }
		              virtual PointPairInteractionPointer Create( unsigned int TheId = GET_NEW_ID, Vector *UsePeriodicBox = NULL )
		              {
		               return( new PointPairInteraction( TheId ) );
		              }
			      
			      virtual double PointPairPotential( Particle& P1, Particle& P2 );
			      virtual Vector PointPairForce( Particle& P1, Particle& P2 );
			   
			      double PointPairPotential( unsigned int ID1, unsigned int ID2 );
			      Vector PointPairForce( unsigned int ID1, unsigned int ID2 );
			     
		              virtual double InteractionPotential( void );
			      virtual Vector InteractionForce( unsigned int ID );   
			     };

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

#endif