amberTorsion.h

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// -*- Mode: C++; tab-width: 2; -*-
// vi: set ts=2:
//

// Molecular Mechanics: Amber force field, bond stretch component

#ifndef BALL_MOLMEC_AMBER_AMBERTORSION_H
#define BALL_MOLMEC_AMBER_AMBERTORSION_H

#ifndef BALL_COMMON_H
# include <BALL/common.h>
#endif

#ifndef BALL_MOLMEC_PARAMETER_COSINETORSION_H
# include <BALL/MOLMEC/PARAMETER/cosineTorsion.h>
#endif

#ifndef BALL_MOLMEC_COMMON_FORCEFIELDCOMPONENT_H
# include <BALL/MOLMEC/COMMON/forceFieldComponent.h>
#endif

#ifndef BALL_MOLMEC_COMMON_FORCEFIELD_H
# include <BALL/MOLMEC/COMMON/forceField.h>
#endif

namespace BALL 
{
  class BALL_EXPORT AmberTorsion 
    : public ForceFieldComponent
  {
    public:

    #define AMBER_TORSIONS_ENABLED "enable Torsions"


    struct SingleAmberTorsion 
    {
      Atom* atom1;
      Atom* atom2;
      Atom* atom3;
      Atom* atom4;

      float         V;
      unsigned char f;
      float         phase;

      SingleAmberTorsion()
        : atom1(0),
          atom2(0),
          atom3(0),
          atom4(0),
          V(0),
          f(0),
          phase(0)
      {
      }
        

      SingleAmberTorsion(CosineTorsion::SingleData& t)
      {
        atom1 = t.atom1;
        atom2 = t.atom2;
        atom3 = t.atom3;
        atom4 = t.atom4;

        V = t.values.V / t.values.n;
        f = (unsigned char)t.values.f;
        phase = ((2.0 * BALL::Constants::PI)/360.0) * t.values.phase;
      }
    };



    BALL_CREATE(AmberTorsion)

    
    AmberTorsion();

    AmberTorsion(ForceField& force_field);

    AmberTorsion(const AmberTorsion& amber_stretch);

    virtual ~AmberTorsion();



    virtual bool setup()
      throw(Exception::TooManyErrors);



    virtual double updateEnergy();

    virtual void updateForces();


    private:

    /*_ @name Private Attributes  
    */
    //_@{

    /*_ array with the torsions
    */
    vector<SingleAmberTorsion>  torsion_;

    CosineTorsion     torsion_parameters_;
    
    CosineTorsion     improper_parameters_;

    ParameterSection  impropers_;

    //_@}
   
  };
} // namespace BALL 

#endif // BALL_MOLMEC_AMBER_AMBERTORSION_H

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