
/* 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 __AmoebaReferenceHarmonicBondForce_H__
#define __AmoebaReferenceHarmonicBondForce_H__

#include "SimTKUtilities/RealVec.h"
#include <vector>

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

class AmoebaReferenceHarmonicBondForce {

public:
 
    /**---------------------------------------------------------------------------------------
       
        Constructor
       
        --------------------------------------------------------------------------------------- */
 
    AmoebaReferenceHarmonicBondForce( ){};
 
    /**---------------------------------------------------------------------------------------
       
        Destructor
       
        --------------------------------------------------------------------------------------- */
 
    ~AmoebaReferenceHarmonicBondForce( ){};
 
 
     /**---------------------------------------------------------------------------------------
     
        Calculate Amoeba harmonic bond ixns (force and energy)
     
        @param numBonds                number of bonds
        @param posData                 particle positions
        @param particle1               particle 1 indices
        @param particle2               particle 2 indices
        @param bondLength              bond length
        @param bondK                   bond force
        @param bondCubic               cubic bond force parameter
        @param bondQuartic             quartic bond force parameter
        @param forces                  output force vector
     
        @return total energy
     
        --------------------------------------------------------------------------------------- */
     
    RealOpenMM calculateForceAndEnergy( int numBonds, std::vector<OpenMM::RealVec>& posData,
                                        const std::vector<int>& particle1,
                                        const std::vector<int>&  particle2,
                                        const std::vector<RealOpenMM>& bondLength,
                                        const std::vector<RealOpenMM>& bondK,
                                        RealOpenMM bondCubic, RealOpenMM bondQuartic,
                                        std::vector<OpenMM::RealVec>& forceData ) const;

private:

     /**---------------------------------------------------------------------------------------
     
        Calculate Amoeba harmonic bond ixns (force and energy)
     
        @param positionAtomA           Cartesian coordinates of atom A
        @param positionAtomB           Cartesian coordinates of atom B
        @param bondLength              bond length
        @param bondK                   bond force
        @param bondCubic               cubic bond force parameter
        @param bondQuartic             quartic bond force parameter
        @param forces                  force vector
     
        @return energy
     
        --------------------------------------------------------------------------------------- */
     
    RealOpenMM calculateBondIxn( const OpenMM::RealVec& positionAtomA, const OpenMM::RealVec& positionAtomB,
                                 RealOpenMM bondLength, RealOpenMM bondK,
                                 RealOpenMM bondCubic, RealOpenMM bondQuartic,
                                 OpenMM::RealVec* forces ) const;
     
};

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

#endif // _AmoebaReferenceHarmonicBondForce___
