TrackRoiSelector.cxx

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/*
  Copyright (C) 2002-2026 CERN for the benefit of the ATLAS collaboration
*/


#include "TrigSteeringEvent/TrigRoiDescriptor.h"

#include "TrackRoiSelector.h"
#include "TrackView.h"

#include <cmath> // std::fabs
#include <algorithm> // for std::find
 
#include "TrigInDetAnalysis/TIDARoiDescriptor.h"

template<class T>
bool IDTPM2::TrackRoiSelector::accept( const T& t, const TrigRoiDescriptor* r ) const {
 
  if ( r==0 ) return true; 
 
  if ( t.pt()==0 ) return false; // throw runtime_error(shouldn't ever have a track with pt = 0" );
    
  if( r->composite() ) {       
 
    for ( unsigned i=r->size() ; i-- ; ) if ( accept( t, (const TrigRoiDescriptor*)r->at(i) ) ) return true;
 
  }
  else { 
 
    if( r->isFullscan() ) return true;
 
    //    std::cout << "r->
    
    bool contained_phi = ( r->phiMinus()<r->phiPlus() ) ?
                         ( t.phi()>r->phiMinus() && t.phi()<r->phiPlus() ) :
                         ( t.phi()>r->phiMinus() || t.phi()<r->phiPlus() ); 

    bool contained_zed = ( t.z0()>r->zedMinus() && t.z0()<r->zedPlus() ); 
    
    bool contained_eta = ( t.eta()<r->etaPlus() && t.eta()>r->etaMinus() );
                                                         
 
#if 0
    //  RoiDescriptor so that computes and stores it's exit points as standard
 
    exit_point ex;
    exit_point explus;
    exit_point exminus;
 
    TIDARoiDescriptor::exitpoint( t.z0(), t.eta(), ex.z, ex.r );
 
    TIDARoiDescriptor::exitpoint( r->zedPlus(),   r->etaPlus(),   explus.z,  explus.r );
    TIDARoiDescriptor::exitpoint( r->zedMinus(),  r->etaMinus(), exminus.z, exminus.r );
 
#else
    
    exit_point ex      = getExitPoint( t.z0(),  t.eta() );
    exit_point explus  = getExitPoint( r->zedPlus(),  r->etaPlus() );
    exit_point exminus = getExitPoint( r->zedMinus(), r->etaMinus() );
#endif
 
    float cross0 = ex.z*exminus.r - ex.r*exminus.z;
    float cross1 = ex.z*explus.r  - ex.r*explus.z; 
 
    contained_eta = ( cross0>0 && cross1<0 ) ? true : false;

    std::optional<double> newphi = getOuterPhi( t.pt(), t.phi(), ex.r );
 
    if( !newphi ) return false;
  
    if( r->phiMinus() < r->phiPlus() ) contained_phi &= ( newphi > r->phiMinus() && newphi < r->phiPlus() );
    else                               contained_phi &= ( newphi > r->phiMinus() || newphi < r->phiPlus() );
 
    if( contained_eta && contained_phi && contained_zed ) return true;
  }
 
  return false;
}
 
 

template bool IDTPM2::TrackRoiSelector::accept( const TrackView& t, const TrigRoiDescriptor* r ) const;
 

std::optional<double> IDTPM2::TrackRoiSelector::getOuterPhi( float pt, float phi, float r ) const {

 
  
  double mqR    = 10 * pt / ( 2.99792458 * 2 ); // 2.998=speed of light, 2=Atlas B field   
  double ratio  = 0.5 * r / mqR;    
  double newphi = phi;
  
  if ( std::fabs(ratio)>1 ) return std::nullopt;
  
  newphi -= std::asin( ratio );  
                          
  while( newphi < -M_PI ) newphi += 2 * M_PI;
  while( newphi > M_PI  ) newphi -= 2 * M_PI;
 
  return newphi;
}
 

 
#if 1
IDTPM2::TrackRoiSelector::exit_point IDTPM2::TrackRoiSelector::getExitPoint( float tz0, float teta ) const {
 
  exit_point exitPoint;
 
  double  rexit = 0;
  double  zexit = 0;
  const double maxRadius = 1000.;
  const double maxZed    = 2700.;
 
  if      ( teta < 0 ) zexit = -maxZed;
  else if ( teta > 0 ) zexit =  maxZed;
  else { 
    exitPoint.z = tz0;
    exitPoint.r = maxRadius; 
    return exitPoint;
  }
  
  double tantheta = std::tan( 2 * std::atan( std::exp( -teta ) ) );
  
  rexit = ( zexit - tz0 ) * tantheta; 

  if ( std::fabs(rexit) > maxRadius ) {
 
    zexit = maxRadius / tantheta + tz0;
    rexit = maxRadius;
  }
 
  exitPoint.z = zexit;
  exitPoint.r = rexit;
  
  return exitPoint;
}
 
#endif