WTrackParameter.cxx

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#include "VertexFit/WTrackParameter.h"
 
WTrackParameter::WTrackParameter() {
  m_w              = HepVector( 7, 0 );
  m_Ew             = HepSymMatrix( 7, 0 );
  m_charge         = 0;
  m_type           = 1;
  m_mass           = 0;
  m_massInvariable = true;
}
 
WTrackParameter::WTrackParameter( const WTrackParameter& wtrk ) {
  m_charge         = wtrk.m_charge;
  m_w              = wtrk.m_w;
  m_Ew             = wtrk.m_Ew;
  m_type           = wtrk.m_type;
  m_plmp           = wtrk.m_plmp;
  m_Vplm           = wtrk.m_Vplm;
  m_mass           = wtrk.m_mass;
  m_massInvariable = wtrk.m_massInvariable;
}
 
WTrackParameter& WTrackParameter::operator=( const WTrackParameter& wtrk ) {
  if ( this == &wtrk ) return *this;
  m_charge         = wtrk.m_charge;
  m_type           = wtrk.m_type;
  m_w              = wtrk.m_w;
  m_Ew             = wtrk.m_Ew;
  m_plmp           = wtrk.m_plmp;
  m_Vplm           = wtrk.m_Vplm;
  m_mass           = wtrk.m_mass;
  m_massInvariable = wtrk.m_massInvariable;
  return *this;
}
 
HepVector WTrackParameter::philambdamass() {
  HepVector tmp( 4, 0 );
  if ( w()[1] >= 0 ) tmp[0] = atan( w()[1] / ( w()[0] ) );
  else tmp[0] = atan( w()[1] / ( w()[0] ) ) + 3.1415926;
  tmp[1] = w()[2] / sqrt( w()[0] * w()[0] + w()[1] * w()[1] );
  tmp[2] = p().m();
  tmp[3] = sqrt( w()[3] * w()[3] - p().m() * p().m() );
  return tmp;
}
 
WTrackParameter::WTrackParameter( const int charge, const HepLorentzVector& p,
                                  const HepPoint3D& x, const double err[] ) {
  HepSymMatrix error( 5, 0 );
  int          k = 0;
  for ( int i = 0; i < 5; i++ )
  {
    for ( int j = i; j < 5; j++ )
    {
      error[i][j] = err[k];
      error[j][i] = err[k];
      k++;
    }
  }
  *this = WTrackParameter( charge, p, x, error );
}
 
WTrackParameter::WTrackParameter( const int charge, const HepLorentzVector& p,
                                  const HepPoint3D& x, const HepSymMatrix& err ) {
  m_w              = HepVector( 7, 0 );
  m_Ew             = HepSymMatrix( 7, 0 );
  m_charge         = charge;
  m_type           = 1;
  m_mass           = p.m();
  m_massInvariable = true;
  for ( int i = 0; i < 4; i++ ) m_w[i] = p[i];
  for ( int i = 0; i < 3; i++ ) m_w[i + 4] = x[i];
 
  HepVector helix( 5, 0 );
  double    phi0 = atan2( -p[0], p[1] );
  if ( cos( phi0 ) != 0 ) helix[0] = x[0] / cos( phi0 );
  else helix[0] = x[1] / sin( phi0 );
  helix[1] = phi0;
  helix[2] = charge / p.perp();
  helix[3] = x[2];
  helix[4] = p[3] / p.perp();
  HepMatrix dWdA( 7, 5, 0 );
  dWdA = GetCvtMatrix( p.m(), helix );
  m_Ew = err.similarity( dWdA );
}
 
WTrackParameter::WTrackParameter( const double mass, const HepVector& hel,
                                  const double err[] ) {
  HepSymMatrix error( 5, 0 );
  int          k = 0;
  for ( int i = 0; i < 5; i++ )
  {
    for ( int j = i; j < 5; j++ )
    {
      error[i][j] = err[k];
      error[j][i] = err[k];
      k++;
    }
  }
  *this = WTrackParameter( mass, hel, error );
}
 
WTrackParameter::WTrackParameter( const double mass, const HepVector& hel,
                                  const HepSymMatrix& err ) {
  m_type = 1;
  m_mass = mass;
  m_w    = HepVector( 7, 0 );
  m_Ew   = HepSymMatrix( 7, 0 );
  HepMatrix dWdA( 7, 5, 0 );
  dWdA             = GetCvtMatrix( mass, hel );
  m_Ew             = err.similarity( dWdA );
  m_w              = CvtH2W( mass, hel );
  m_charge         = hel[2] > 0 ? +1 : -1;
  m_massInvariable = true;
}
 
WTrackParameter::WTrackParameter( const HepLorentzVector& p, const double dphi,
                                  const double dthe, const double dE ) {
  HepPoint3D x( 0, 0, 0 );
  *this = WTrackParameter( x, p, dphi, dthe, dE );
}
 
WTrackParameter::WTrackParameter( const HepPoint3D& x, const HepLorentzVector& p,
                                  const double dphi, const double dthe, const double dE ) {
  m_w              = HepVector( 7, 0 );
  m_Ew             = HepSymMatrix( 7, 0 );
  m_type           = 2;
  m_mass           = p.m();
  m_charge         = 0;
  m_massInvariable = true;
  for ( int i = 0; i < 4; i++ ) m_w[i] = p[i];
  for ( int i = 0; i < 3; i++ ) m_w[i + 4] = x[i];
 
  HepMatrix dwda( 7, 3, 0 );
  dwda[0][0] = -p.py();
  dwda[1][0] = p.px();
  dwda[4][0] = -x.y();
  dwda[5][0] = x.x();
 
  dwda[0][1] = p.px() * p.pz() / p.perp();
  dwda[1][1] = p.py() * p.pz() / p.perp();
  dwda[2][1] = -p.perp();
  dwda[6][1] = -x.distance2() / sqrt( x.x() * x.x() + x.y() * x.y() );
 
  dwda[0][2] = p.px() / p.rho();
  dwda[1][2] = p.py() / p.rho();
  dwda[2][2] = p.pz() / p.rho();
  dwda[3][2] = p.rho() / p.e();
  // dwda[4][2] = x.x()/(x.x()*x.x()+x.y()*x.y());
  // dwda[5][2] = x.y()/(x.x()*x.x()+x.y()*x.y());
  // dwda[6][2] = x.z()/(x.x()*x.x()+x.y()*x.y());
 
  HepSymMatrix emcmea( 3, 0 );
  emcmea[0][0] = dphi * dphi;
  emcmea[1][1] = dthe * dthe;
  emcmea[2][2] = dE * dE;
  m_Ew         = emcmea.similarity( dwda );
}
 
HepMatrix WTrackParameter::GetCvtMatrix( const double     mass,
                                         const HepVector& helix ) // just suitable for charged
                                                                  // tracks
{
  HepMatrix m( 7, 5, 0 );
  double    drho   = helix[0];
  double    phi0   = helix[1];
  double    kappa  = helix[2];
  double    kappa2 = kappa * kappa;
  double    kappa3 = kappa * kappa2;
  // double dz      = helix[3];
  double lambda  = helix[4];
  double lambda2 = lambda * lambda;
  double e       = sqrt( ( 1 + lambda2 ) / kappa2 + mass * mass );
  double sinphi0 = sin( phi0 );
  double cosphi0 = cos( phi0 );
  int    q       = ( kappa > 0 ) ? 1 : ( -1 );
  m[0][1]        = -cosphi0 * q / kappa;
  m[0][2]        = sinphi0 * q / kappa2;
  m[1][1]        = -sinphi0 * q / kappa;
  m[1][2]        = -cosphi0 * q / kappa2;
  m[2][2]        = -lambda * q / kappa2;
  m[2][4]        = q / kappa;
  m[3][2]        = -( 1 + lambda2 ) / ( kappa3 * e );
  m[3][4]        = lambda / ( kappa2 * e );
  m[4][0]        = cosphi0;
  m[4][1]        = -drho * sinphi0;
  m[5][0]        = sinphi0;
  m[5][1]        = drho * cosphi0;
  m[6][3]        = 1;
  return m;
}
 
HepVector WTrackParameter::CvtH2W( const double mass, const HepVector& helix ) {
  double    drho    = helix[0];
  double    phi0    = helix[1];
  double    kappa   = helix[2];
  double    dz      = helix[3];
  double    lambda  = helix[4];
  double    sinphi0 = sin( phi0 );
  double    cosphi0 = cos( phi0 );
  int       q       = ( kappa > 0 ) ? 1 : ( -1 );
  HepVector w( 7, 0 );
  w[0] = -sinphi0 * q / kappa;
  w[1] = cosphi0 * q / kappa;
  w[2] = lambda * q / kappa;
  w[3] = sqrt( ( 1 + lambda * lambda ) / ( kappa * kappa ) + mass * mass );
  w[4] = drho * cosphi0;
  w[5] = drho * sinphi0;
  w[6] = dz;
  return w;
}