TruthParticleParentAssociationTool.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
// $Id$
#include "TruthParticleParentAssociationTool.h"
#include "xAODTruth/TruthVertex.h"
#include "AthenaKernel/errorcheck.h"
#include "TruthUtils/MagicNumbers.h"
 
namespace D3PD {
 
 
TruthParticleParentAssociationTool::TruthParticleParentAssociationTool
  (const std::string& type,
   const std::string& name,
   const IInterface* parent)
    : Base (type, name, parent),
      m_i (0)
{}
 
 
StatusCode TruthParticleParentAssociationTool::initialize()
{
  return Base::initialize();
}
 
 
StatusCode
TruthParticleParentAssociationTool::reset (const xAOD::TruthParticle& p)
{
  const xAOD::TruthVertex* vx = p.prodVtx();
  if (!vx)
    m_parents.clear();
  else {
    size_t sz = vx->nIncomingParticles();
    m_parents.resize (sz);
    for (unsigned int i = 0; i < sz; i++)
      m_parents[i] = vx->incomingParticle(i);
    std::sort (m_parents.begin(), m_parents.end(), [](const auto & a, const auto & b) -> bool{ return HepMC::uniqueID(a) < HepMC::uniqueID(b); }); // FIXME barcode-based - ordering may change when this function switches to returning id rather than barcode
    m_i = 0;
  }
  return StatusCode::SUCCESS;
}
 
 
const xAOD::TruthParticle* TruthParticleParentAssociationTool::next()
{
  if (m_i < m_parents.size())
    return m_parents[m_i++];
  return 0;
}
 
 
} // namespace D3PD