ChargeService.cxx

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//=================================================
//
//
// find particle charge
//
//=================================================
#include "AtlfastEvent/ChargeService.h"
#include "GaudiKernel/IPartPropSvc.h"
#include "GaudiKernel/Bootstrap.h"
#include "GaudiKernel/ISvcLocator.h"
#include "HepPDT/ParticleData.hh"
#include <sstream>

namespace Atlfast {
  using std::abs;

  ChargeService::ChargeService(){

    IPartPropSvc* p_PartPropSvc;
    static const bool CREATEIFNOTTHERE(true);
    ISvcLocator* svcLoc = Gaudi::svcLocator( );
    StatusCode PartPropStatus = svcLoc->service("PartPropSvc", 
                                                p_PartPropSvc, 
                                                CREATEIFNOTTHERE
                                                );
    if (!PartPropStatus.isSuccess() || 0 == p_PartPropSvc) {
      std::cerr<<"ChargeService: could not find PartPropService"<<std::endl;
      std::string errMsg = "ChargeService: could not find PartPropService";
      throw errMsg;
    }      
    m_particleDataTable = (HepPDT::ParticleDataTable*)p_PartPropSvc->PDT();
    if(m_particleDataTable == 0){
      std::cerr<< "ChargeService: PDG table not found"<<std::endl;
      std::string errMsg = "ChargeService: PDG table not found";
      throw errMsg;
    }


    //make a test read of the table
    HepPDT::ParticleData* ap = 
      m_particleDataTable->particle( 211 );
    
    if(!ap){ 
      std::cerr<< "ChargeService: Test read of PDG table failed"<<std::endl;
      std::string errMsg = "ChargeService: Test read of PDG table failed";
      throw errMsg;
    }
    

  }
  ChargeService::ChargeService(const ChargeService & other):
    m_particleDataTable(other.m_particleDataTable){}
  
  double ChargeService::operator()(const HepMC::GenParticle* p)const {
    
    //does particle exist in table only positive ids for neutrals !?
    HepPDT::ParticleData* ap = 
      m_particleDataTable->particle( abs( p->pdg_id() ) );
    
    if(!ap){ 
      std::cout << "Atlfast::ChargeService: PDGID " << p->pdg_id()
                << " is not in ParticleDataTable!!!" << std::endl;
      return -999.;
    }
    
    //if in table, and the charge is 0, return 0. 
    double c = ap->charge();
    if(c==0){ return 0.;}
    return (p->pdg_id() > 0)? c:-c;
    
  }
 
  double ChargeService::operator()(const ReconstructedParticle* p)const {
    return (*this)(p->truth());
  }
 
}

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