/*   []----------------------------------------[]
      |                Coulomb.h               |
     []----------------------------------------[]
      |                                        |
      |   AUTHOR:    MFSomers 2005.            |
      |   USE:       Defines a coulomb type    |
      |               interaction...           |
      |                                        |
     []----------------------------------------[]
*/

// 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(__COULOMB_INCLUDED__)

#define __COULOMB_INCLUDED__

#include "Global.h"
#include "Vector.h"
#include "Constants.h"
#include "ClassicalDynamics.h"
#include "PointPair.h"

#define COULOMB_VACUUM_CONSTANT (1.0/(4.0*CONST_PI*CONST_VACUUM_PERMITTIVITY))

/* --------------------------------------------------------- */
/* Defines a coulomb pointpair interaction between particles */

class   CoulombInteraction;
typedef CoulombInteraction *CoulombInteractionPointer;

class CoulombInteraction : public PointPairInteraction
                           {
			    public:
			     
			    inline CoulombInteraction( double TheFactor = COULOMB_VACUUM_CONSTANT, unsigned int TheId = GET_NEW_ID, Vector *UsePeriodicBox = NULL ) : PointPairInteraction( TheId, UsePeriodicBox )
			    {
			     InteractionFactor = TheFactor;
			     Type = ACoulombInteraction;
			    };
			    inline CoulombInteraction( CoulombInteraction& I ) : PointPairInteraction( I )
			    {
			     InteractionFactor = I.InteractionFactor;
			    }

			    virtual CoulombInteraction& operator=( CoulombInteraction& I )
			    {
			     if( &I == &(*this) ) return( (*this) );
			     PointPairInteraction::operator=( I );
			     InteractionFactor = I.InteractionFactor;
			     return( (*this) );
			    } 			    
			    virtual CoulombInteractionPointer Clone()
		            {
		             return( new CoulombInteraction( (*this) ) );
		            }
		            virtual CoulombInteractionPointer Create( double TheFactor = COULOMB_VACUUM_CONSTANT, unsigned int TheId = GET_NEW_ID, Vector *UsePeriodicBox = NULL )
		            {
		             return( new CoulombInteraction( TheFactor, TheId, UsePeriodicBox ) );
		            }			    
				    
			    virtual double PointPairPotential( Particle& P1, Particle& P2 );
			    virtual Vector PointPairForce( Particle& P1, Particle& P2 );
			    
			    double InteractionFactor;
			   };
			   
/* --------------------------------------------------------- */

#endif