McEventCollectionCnv_p2.cxx

///////////////////////// -*- C++ -*- /////////////////////////////

/*
  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
*/

// McEventCollectionCnv_p2.cxx
// Implementation file for class McEventCollectionCnv_p2
// Author: S.Binet<binet@cern.ch>
///////////////////////////////////////////////////////////////////


// STL includes
#include <utility>

// GeneratorObjectsTPCnv includes
#include "GeneratorObjectsTPCnv/McEventCollectionCnv_p2.h"
#include "HepMcDataPool.h"

#if 0
namespace {
  // helper method to compute the number of particles and vertices in a
  // whole McEventCollection
  std::pair<unsigned int,unsigned int>
  nbrParticlesAndVertices( const McEventCollection* mcEvents ) {
    unsigned int nParts = 0;
    unsigned int nVerts = 0;
    const McEventCollection::const_iterator itrEnd = mcEvents->end();
    for ( McEventCollection::const_iterator itr = mcEvents->begin();
          itr != itrEnd;
          ++itr ) {
      nParts += (*itr)->particles_size();
      nVerts += (*itr)->vertices_size();
    }

    return std::make_pair( nParts, nVerts );
  }
}
#endif

///////////////////////////////////////////////////////////////////
// Public methods:
///////////////////////////////////////////////////////////////////

// Constructors
////////////////
McEventCollectionCnv_p2::McEventCollectionCnv_p2() :
  Base_t( )
{}

McEventCollectionCnv_p2::McEventCollectionCnv_p2( const McEventCollectionCnv_p2& rhs ) :
  Base_t( rhs )
{}

McEventCollectionCnv_p2&
McEventCollectionCnv_p2::operator=( const McEventCollectionCnv_p2& rhs )
{
  if ( this != &rhs ) {
    Base_t::operator=( rhs );
  }
  return *this;
}

// Destructor
///////////////

McEventCollectionCnv_p2::~McEventCollectionCnv_p2()
{
}

///////////////////////////////////////////////////////////////////
// Const methods:
///////////////////////////////////////////////////////////////////

void McEventCollectionCnv_p2::persToTrans( const McEventCollection_p2* persObj,
                                           McEventCollection* transObj,
                                           MsgStream& msg )
{
  msg << MSG::DEBUG << "Loading McEventCollection from persistent state..."
      << endmsg;

  // elements are managed by DataPool
  transObj->clear(SG::VIEW_ELEMENTS);
  HepMC::DataPool datapools;
  const unsigned int nVertices = persObj->m_genVertices.size();
  if ( datapools.vtx.capacity() - datapools.vtx.allocated() < nVertices ) {
    datapools.vtx.reserve( datapools.vtx.allocated() + nVertices );
  }
  const unsigned int nParts = persObj->m_genParticles.size();
  if ( datapools.part.capacity() - datapools.part.allocated() < nParts ) {
    datapools.part.reserve( datapools.part.allocated() + nParts );
  }
  const unsigned int nEvts = persObj->m_genEvents.size();
  if ( datapools.evt.capacity() - datapools.evt.allocated() < nEvts ) {
    datapools.evt.reserve( datapools.evt.allocated() + nEvts );
  }
  DataPool<HepMC::GenEvent>& poolOfEvents = datapools.evt;

  transObj->reserve( nEvts );
  const std::vector<GenEvent_p2>::const_iterator itrEnd = persObj->m_genEvents.end();
  for ( std::vector<GenEvent_p2>::const_iterator itr = persObj->m_genEvents.begin();
        itr != itrEnd;
        ++itr ) {
    const GenEvent_p2& persEvt = *itr;
    HepMC::GenEvent * genEvt        = poolOfEvents.nextElementPtr();
    genEvt->m_signal_process_id     = persEvt.m_signalProcessId;
    genEvt->m_event_number          = persEvt.m_eventNbr;
    genEvt->m_event_scale           = persEvt.m_eventScale;
    genEvt->m_alphaQCD              = persEvt.m_alphaQCD;
    genEvt->m_alphaQED              = persEvt.m_alphaQED;
    genEvt->m_signal_process_vertex = 0;
    genEvt->m_weights               = persEvt.m_weights;
    genEvt->m_random_states         = persEvt.m_randomStates;
    genEvt->m_vertex_barcodes.clear();
    genEvt->m_particle_barcodes.clear();
    genEvt->m_pdf_info = 0;         //> not available at that time...

    transObj->push_back( genEvt );

    // create a temporary map associating the barcode of an end-vtx to its
    // particle.
    // As not all particles are stable (d'oh!) we take 50% of the number of
    // particles as an initial size of the hash-map (to prevent re-hash)
    ParticlesMap_t partToEndVtx( (persEvt.m_particlesEnd-
                                  persEvt.m_particlesBegin)/2 );

    // create the vertices
    const unsigned int endVtx = persEvt.m_verticesEnd;
    for ( unsigned int iVtx= persEvt.m_verticesBegin; iVtx != endVtx; ++iVtx ) {
      genEvt->add_vertex( createGenVertex( *persObj,
                                           persObj->m_genVertices[iVtx],
                                           partToEndVtx,
                                           &datapools ) );
    } //> end loop over vertices

    // set the signal process vertex
    const int sigProcVtx = persEvt.m_signalProcessVtx;
    if ( sigProcVtx != 0 ) {
      genEvt->set_signal_process_vertex( genEvt->barcode_to_vertex( sigProcVtx ) );
    }

    // connect particles to their end vertices
    const ParticlesMap_t::iterator endItr = partToEndVtx.end();
    for ( ParticlesMap_t::iterator p = partToEndVtx.begin();
          p != endItr;
          ++p ) {
      HepMC::GenVertexPtr decayVtx = genEvt->barcode_to_vertex( p->second );
      if ( decayVtx ) {
        decayVtx->add_particle_in( p->first );
      } else {
        msg << MSG::ERROR
            << "GenParticle points to null end vertex !!"
            << endmsg;
      }
    }
  } //> end loop over m_genEvents

  msg << MSG::DEBUG << "Loaded McEventCollection from persistent state [OK]"
      << endmsg;

  return;
}

void McEventCollectionCnv_p2::transToPers( const McEventCollection*,
                                           McEventCollection_p2*,
                                           MsgStream& msg )
{
  msg << MSG::DEBUG << "Creating persistent state of McEventCollection..."
      << endmsg;

  msg << MSG::ERROR
      << "This transient-to-persistent converter method has been RETIRED !!"
      << endmsg
      << "You are not supposed to end-up here ! Go away !"
      << endmsg;

  throw std::runtime_error( "Retired McEventCollectionCnv_p2::transToPers() !!" );
  return;
}

///////////////////////////////////////////////////////////////////
// Non-const methods:
///////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////
// Protected methods:
///////////////////////////////////////////////////////////////////

HepMC::GenVertexPtr
McEventCollectionCnv_p2::createGenVertex( const McEventCollection_p2& persEvt,
                                          const GenVertex_p2& persVtx,
                                          ParticlesMap_t& partToEndVtx, HepMC::DataPool* datapools ) const
{
  DataPool<HepMC::GenVertex>& poolOfVertices = datapools->vtx;
  HepMC::GenVertexPtr vtx = poolOfVertices.nextElementPtr();
  vtx->m_position.setX( persVtx.m_x );
  vtx->m_position.setY( persVtx.m_y );
  vtx->m_position.setZ( persVtx.m_z );
  vtx->m_position.setT( persVtx.m_t );
  vtx->m_particles_in.clear();
  vtx->m_particles_out.clear();
  vtx->m_id      = persVtx.m_id;
  vtx->m_weights.m_weights.reserve( persVtx.m_weights.size() );
  vtx->m_weights.m_weights.assign ( persVtx.m_weights.begin(),
                                    persVtx.m_weights.end() );
  vtx->m_event   = 0;
  vtx->m_barcode = persVtx.m_barcode;

  // handle the in-going (orphans) particles
  const unsigned int nPartsIn = persVtx.m_particlesIn.size();
  for ( unsigned int i = 0; i != nPartsIn; ++i ) {
    createGenParticle( persEvt.m_genParticles[persVtx.m_particlesIn[i]],
                       partToEndVtx,
                       datapools );
  }

  // now handle the out-going particles
  const unsigned int nPartsOut = persVtx.m_particlesOut.size();
  for ( unsigned int i = 0; i != nPartsOut; ++i ) {
    vtx->add_particle_out( createGenParticle( persEvt.m_genParticles[persVtx.m_particlesOut[i]],
                                              partToEndVtx,
                                              datapools ) );
  }

  return vtx;
}

HepMC::GenParticlePtr
McEventCollectionCnv_p2::createGenParticle( const GenParticle_p2& persPart,
                                            ParticlesMap_t& partToEndVtx, HepMC::DataPool* datapools ) const
{
  DataPool<HepMC::GenParticle>& poolOfParticles = datapools->part;
  HepMC::GenParticlePtr p    = poolOfParticles.nextElementPtr();
  p->m_momentum.setPx( persPart.m_px  );
  p->m_momentum.setPy( persPart.m_py  );
  p->m_momentum.setPz( persPart.m_pz  );
  p->m_momentum.setE ( persPart.m_ene );
  p->m_pdg_id              = persPart.m_pdgId;
  p->m_status              = persPart.m_status;
  p->m_polarization.m_theta= static_cast<double>(persPart.m_thetaPolarization);
  p->m_polarization.m_phi  = static_cast<double>(persPart.m_phiPolarization  );
  p->m_production_vertex   = 0;
  p->m_end_vertex          = 0;
  p->m_barcode             = persPart.m_barcode;

  // fillin' the flow
  const unsigned int nFlow = persPart.m_flow.size();
  for ( unsigned int iFlow= 0; iFlow != nFlow; ++iFlow ) {
    p->m_flow.set_icode( persPart.m_flow[iFlow].first,
                         persPart.m_flow[iFlow].second );
  }

  if ( persPart.m_endVtx != 0 ) {
    partToEndVtx[p] = persPart.m_endVtx;
  }

  return p;
}