| 1 | //////////////////////////////////////////////////////////////////////////
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| 2 | // Matt.Dobbs@Cern.CH, September 1999
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| 3 | //
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| 4 | // Polarization object for a particle. All angles are in radians.
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| 5 | //////////////////////////////////////////////////////////////////////////
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| 6 |
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| 7 | #include "Polarization.h"
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| 8 |
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| 9 | namespace HepMC {
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| 10 |
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| 11 | Polarization::Polarization( double theta, double phi )
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| 12 | : m_theta( valid_theta(theta) ),
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| 13 | m_phi ( valid_phi(phi) )
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| 14 | { }
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| 15 |
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| 16 | Polarization::Polarization( const Polarization& inpolar )
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| 17 | : m_theta( valid_theta( inpolar.theta() ) ),
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| 18 | m_phi ( valid_phi( inpolar.phi() ) )
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| 19 | { }
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| 20 |
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| 21 | Polarization::Polarization( const ThreeVector& vec3in )
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| 22 | : m_theta( valid_theta( vec3in.theta() ) ),
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| 23 | m_phi ( valid_phi( vec3in.phi() ) )
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| 24 | { }
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| 25 |
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| 26 | void Polarization::swap( Polarization & other)
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| 27 | {
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| 28 | std::swap( m_theta, other.m_theta );
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| 29 | std::swap( m_phi, other.m_phi );
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| 30 | }
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| 31 |
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| 32 | Polarization& Polarization::operator=( const Polarization& inpolar ) {
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| 33 | /// best practices implementation
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| 34 | Polarization tmp( inpolar );
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| 35 | swap( tmp );
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| 36 | return *this;
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| 37 | }
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| 38 |
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| 39 | void Polarization::print( std::ostream& ostr ) const {
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| 40 | ostr << "Polarization: " << *this << std::endl;
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| 41 | }
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| 42 |
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| 43 | ////////////////////
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| 44 | // access methods //
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| 45 | ////////////////////
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| 46 |
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| 47 | ThreeVector Polarization::normal3d() const {
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| 48 | // unit Hep3Vector for easy manipulation
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| 49 | ThreeVector outvec(0,0,1); // makes unit vector along Z
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| 50 | outvec.setTheta( theta() ); // sets phi keeping mag and theta constant
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| 51 | outvec.setPhi( phi() ); // sets theta keeping mag and phi constant
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| 52 | return outvec;
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| 53 | }
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| 54 |
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| 55 | double Polarization::set_theta( double theta ) {
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| 56 | /// Theta is restricted to be between 0 --> pi
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| 57 | /// if an out of range value is given, it is translated to this range.
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| 58 | return m_theta = valid_theta( theta );
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| 59 | }
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| 60 |
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| 61 | double Polarization::set_phi( double phi ) {
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| 62 | /// Phi is restricted to be between 0 --> 2pi
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| 63 | /// if an out of range value is given, it is translated to this range.
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| 64 | return m_phi = valid_phi( phi );
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| 65 | }
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| 66 |
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| 67 | void Polarization::set_theta_phi( double theta, double phi ) {
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| 68 | set_theta( theta );
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| 69 | set_phi( phi ) ;
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| 70 | }
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| 71 |
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| 72 | ThreeVector Polarization::set_normal3d( const ThreeVector& vec3in ) {
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| 73 | set_theta( vec3in.theta() );
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| 74 | set_phi( vec3in.phi() );
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| 75 | return vec3in;
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| 76 | }
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| 77 |
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| 78 | /////////////////////
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| 79 | // private methods //
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| 80 | /////////////////////
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| 81 |
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| 82 | double Polarization::valid_theta( double theta ) {
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| 83 | // this is just absolute value.
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| 84 | theta = ( theta>0 ? theta : -theta );
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| 85 | // translate to 0 < theta < 2pi
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| 86 | theta = ( theta/(2*HepMC_pi) - int(theta/(2*HepMC_pi)) )
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| 87 | * 2*HepMC_pi;
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| 88 | // now translate to 0 < theta < pi
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| 89 | if ( theta > HepMC_pi ) theta = 2*HepMC_pi - theta;
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| 90 | return theta;
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| 91 | }
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| 92 |
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| 93 | double Polarization::valid_phi( double phi ) {
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| 94 | //
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| 95 | // translate to -2pi < phi < 2pi
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| 96 | phi = ( phi/(2*HepMC_pi) - int(phi/(2*HepMC_pi)) ) * 2*HepMC_pi;
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| 97 | // translates to 0 < phi < 2pi
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| 98 | if ( phi < 0 ) phi = 2*HepMC_pi + phi;
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| 99 | return phi;
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| 100 | }
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| 101 |
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| 102 | /////////////
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| 103 | // Friends //
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| 104 | /////////////
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| 105 |
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| 106 | /// write theta and phi to the output stream
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| 107 | std::ostream& operator<<( std::ostream& ostr, const Polarization& polar ) {
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| 108 | return ostr << "(" << polar.theta()
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| 109 | << "," << polar.phi() << ")";
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| 110 | }
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| 111 |
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| 112 | } // HepMC
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| 113 |
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| 114 |
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