Simulation::GenEventVertexPositioner Class Reference

#include <GenEventVertexPositioner.h>

Inheritance diagram for Simulation::GenEventVertexPositioner:

Collaboration diagram for Simulation::GenEventVertexPositioner:

Public Member Functions
	GenEventVertexPositioner (const std::string &t, const std::string &n, const IInterface *p)
	Constructor with parameters. More...
StatusCode	initialize () override final
	Athena algtool's Hooks. More...
StatusCode	finalize () override final
	Athena algtool's Hooks. More...
StatusCode	manipulate (HepMC::GenEvent &ge, const EventContext &ctx) const override final
	modifies (displaces) the given GenEvent More...

Private Attributes
ToolHandleArray< ILorentzVectorGenerator >	m_vertexShifters {this, "VertexShifters", {}}
	Vertex Shifters applied in the given order. More...

Detailed Description

This tool takes a HepMC::GenEvent and applies geometrical modifications, such as random vertex smearing, beam tilt, etc.

based on: https://svnweb.cern.ch/trac/atlasoff/browser/Simulation/G4Atlas/G4AtlasUtilities/trunk/src/VertexPositioner.cxx

Author

Andreas.Salzburger -at- cern.ch , Elmar.Ritsch -at- cern.ch

Definition at line 29 of file GenEventVertexPositioner.h.

Constructor & Destructor Documentation

GenEventVertexPositioner()

Simulation::GenEventVertexPositioner::GenEventVertexPositioner	(	const std::string &	t,
		const std::string &	n,
		const IInterface *	p
	)

Constructor with parameters.

Constructor.

Definition at line 21 of file GenEventVertexPositioner.cxx.

    : base_class(t,n,p)
  {
  }

Member Function Documentation

finalize()

StatusCode Simulation::GenEventVertexPositioner::finalize ( )

finaloverride

Athena algtool's Hooks.

Definition at line 42 of file GenEventVertexPositioner.cxx.

  {
    ATH_MSG_VERBOSE("Finalizing ...");
    return StatusCode::SUCCESS;
  }

initialize()

StatusCode Simulation::GenEventVertexPositioner::initialize ( )

finaloverride

Athena algtool's Hooks.

Definition at line 29 of file GenEventVertexPositioner.cxx.

  {
    ATH_MSG_VERBOSE("Initializing ...");
 
    // retrieve Vertex Shifters
    if ( !m_vertexShifters.empty() ) {
      ATH_CHECK(m_vertexShifters.retrieve());
    }
 
    return StatusCode::SUCCESS;
  }

manipulate()

StatusCode Simulation::GenEventVertexPositioner::manipulate ( HepMC::GenEvent &  ge, const EventContext &  ctx  ) const

finaloverride

modifies (displaces) the given GenEvent

Definition at line 49 of file GenEventVertexPositioner.cxx.

  {
    // Grab signal_process_vertex pointer
    auto signalProcVtx=HepMC::signal_process_vertex(&ge);
    if(!signalProcVtx) {
      ATH_MSG_ERROR("Expected GenEvent::signal_process_vertex() to already have been set at this point!");
      return StatusCode::FAILURE;
    }
 
    // loop over all given ILorentzVectorGenerator AlgTools
    for (const auto& vertexShifter : m_vertexShifters) {
 
      // call VertexShifter and let it compute the current shift
      CLHEP::HepLorentzVector *curShift = vertexShifter->generate(ctx);
      if (!curShift) {
        ATH_MSG_ERROR("Vertex Shifter AthenaTool returned zero-pointer! Ignore.");
        continue;
      }
 
      ATH_MSG_VERBOSE("Retrieved Vertex shift of: " << *curShift << " from " << vertexShifter->name());
 
      // As signal process vertex is a pointer, there is some risk
      // that the pointer points to a vertex somewhere else in the
      // event, rather than a unique / new vertex, in which case we
      // will modify its position in the loop below and will not need
      // to treat it separately.
      bool modifySigVtx(true);
 
      // loop over the vertices in the event, they are in respect with another
      //   (code from Simulation/Fatras/FatrasAlgs/McEventPreProcessing.cxx)
#ifdef HEPMC3
      for(auto& curVtx: ge.vertices()) {
        // NB Doing this check to explicitly avoid the fallback mechanism in
        // HepMC3::GenVertex::position() to return the position of
        // another GenVertex in the event if the position isn't set (or is set to zero)!
        const HepMC::FourVector &curPos = (curVtx->has_set_position()) ? curVtx->position() : HepMC::FourVector::ZERO_VECTOR();
#else
      auto vtxIt    = ge.vertices_begin();
      auto vtxItEnd = ge.vertices_end();
      for( ; vtxIt != vtxItEnd; ++vtxIt) {
        // quick access:
        auto curVtx = (*vtxIt);
        const HepMC::FourVector &curPos = curVtx->position();
#endif
 
        // get a copy of the current vertex position
        CLHEP::HepLorentzVector newPos( curPos.x(), curPos.y(), curPos.z(), curPos.t() );
        // and update it with the given smearing
        newPos += (*curShift);
 
        ATH_MSG_VERBOSE( "Original vtx  position = " << curPos.x() << ", " << curPos.y() << ", " << curPos.z() );
        ATH_MSG_VERBOSE( "Updated  vtx  position = " << newPos );
 
        // store the updated position in the vertex
        curVtx->set_position( HepMC::FourVector(newPos.x(),newPos.y(),newPos.z(),newPos.t()));
        if(modifySigVtx && signalProcVtx==curVtx) {
          modifySigVtx=false;
        }
      }
 
      // Do the same for the signal process vertex if still required.
      if (modifySigVtx) {
        const HepMC::FourVector &curPos = HepMC::signal_process_vertex(&ge)->position();
        CLHEP::HepLorentzVector newPos( curPos.x(), curPos.y(), curPos.z(), curPos.t() );
        newPos += (*curShift);
        (HepMC::signal_process_vertex(&ge))->set_position( HepMC::FourVector(newPos.x(),newPos.y(),newPos.z(),newPos.t()) );
      }
 
      // memory cleanup
      delete curShift;
    }
 
    return StatusCode::SUCCESS;
  }

Member Data Documentation

m_vertexShifters

ToolHandleArray<ILorentzVectorGenerator> Simulation::GenEventVertexPositioner::m_vertexShifters {this, "VertexShifters", {}}

private

Vertex Shifters applied in the given order.

Definition at line 44 of file GenEventVertexPositioner.h.

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The documentation for this class was generated from the following files:

• GenEventVertexPositioner.h
• GenEventVertexPositioner.cxx