Polarization.h

//--------------------------------------------------------------------------
#ifndef HEPMC_POLARIZATION_H
#define HEPMC_POLARIZATION_H

// Matt.Dobbs@Cern.CH, September 1999, refer to:
// M. Dobbs and J.B. Hansen, "The HepMC C++ Monte Carlo Event Record for
// High Energy Physics", Computer Physics Communications (to be published).
//
// Polarization object for a particle. All angles are in radians.

#include "HepMC/SimpleVector.h"
#include <iostream>
#include <cmath>

namespace HepMC {

    static const double HepMC_pi = 3.14159265358979323846;  // copy of pi from CLHEP
    

    class Polarization {

        friend std::ostream& operator<<( std::ostream&, const Polarization& );

    public:
        Polarization( );
        Polarization( double theta, double phi = 0 );
        Polarization( const Polarization& inpolar );
        Polarization( const ThreeVector& vec3in );
        virtual       ~Polarization() {}

        void swap( Polarization & other);
        Polarization& operator=( const Polarization& inpolar );
        bool          operator==( const Polarization& ) const;
        bool          operator!=( const Polarization& ) const;

        void          print( std::ostream& ostr = std::cout ) const;
    
        // access methods //
        double        theta() const;    
        double        phi() const;      
        ThreeVector   normal3d() const; 
        bool          is_defined() const;   

        double        set_theta( double theta );
        double        set_phi( double phi );
        void          set_theta_phi( double theta, double phi );
        ThreeVector   set_normal3d( const ThreeVector& vec3in ); 
        void          set_undefined();

    private:
        double valid_theta( double theta );
        double valid_phi( double phi );

    private:
        double m_theta; //polar angle of polarization in radians 0< theta <pi
        double m_phi;   //azimuthal angle of polarization in rad. 0< phi <2pi
        bool   m_defined; //used to flag if the Polarization has been defined
    };

    // INLINE Access Methods //

    inline double Polarization::theta() const { return m_theta; }
    inline double Polarization::phi() const { return m_phi; }

    // INLINE Operators      //

    inline bool Polarization::operator==( const Polarization& a ) const 
    {
        return ( a.theta() == this->theta() && a.phi() == this->phi() && a.is_defined() == this->is_defined() );
    }

    inline bool Polarization::operator!=(const Polarization& a ) const 
    {
        return !( a == *this );
    }

} // HepMC

#endif  // HEPMC_POLARIZATION_H
//--------------------------------------------------------------------------