Event Class Reference

#include <Event.hh>

Collaboration diagram for Event:

Detailed Description

Rivet wrapper for HepMC event and Projection references.

Event is a concrete class representing an generated event in Rivet. It is constructed given a HepMC::GenEvent, a pointer to which is kept by the Event object throughout its lifetime. The user must therefore make sure that the corresponding HepMC::GenEvent will persist at least as long as the Event object.

In addition to the HepMC::GenEvent object the Event also keeps track of all Projections object which have been applied to the Event so far.

Definition at line 22 of file Event.hh.


Public Member Functions
const GenEvent &	genEvent () const
	Return the generated event obtained from an external event generator.
double	weight () const
	The weight associated with the event.
template<typename PROJ>
const PROJ &	applyProjection (PROJ &p) const
template<typename PROJ>
const PROJ &	applyProjection (PROJ *pp) const
Standard constructors and destructors.
	Event (const GenEvent &ge)
	The default constructor.
	Event (const Event &e)
	The copy constructor.
	~Event ()
	The destructor.
Private Member Functions
void	_geNormAlignment ()
Private Attributes
GenEvent const &	_genEvent
	The generated event, obtained from an external generator. Note that it is only externally accessible via a const reference.
GenEvent *	_modGenEvent
std::set< ConstProjectionPtr >	_projections
	The set of Projection objects applied so far.
double	_weight
	The generation weight associated with the event. Usually 1.0. Only copied from the HepMC event once, at construction time.

Constructor & Destructor Documentation

Event ( const GenEvent & ge )

The default constructor.

Definition at line 66 of file Event.cc.

References Event::_genEvent, Event::_geNormAlignment(), Event::_modGenEvent, and Event::_weight.

00067     : _genEvent(ge), _modGenEvent(NULL), _weight(1.0)
00068   {
00069     // Set the weight if there is one, otherwise default to 1.0
00070     if (!_genEvent.weights().empty()) {
00071       _weight = ge.weights()[0];
00072     }
00073 
00074     // Use Rivet's preferred units if possible
00075     #ifdef HEPMC_HAS_UNITS
00076     if (_genEvent.momentum_unit()!=HepMC::Units::GEV ||
00077         _genEvent.length_unit()!=HepMC::Units::MM) {
00078       if (!_modGenEvent) _modGenEvent = new GenEvent(ge);
00079       _modGenEvent->use_units(HepMC::Units::GEV, HepMC::Units::MM);
00080     }
00081     #endif
00082  
00083     // Use the conventional alignment
00084     _geNormAlignment();
00085 
00086     // Debug printout to check that copying/magling has worked
00087     //_genEvent.print();
00088   }

Event ( const Event & e )

The copy constructor.

Definition at line 91 of file Event.cc.

00092     : _genEvent(e._genEvent), _modGenEvent(e._modGenEvent),
00093       _weight(e._weight)
00094   {
00095     //
00096   }

~Event ( )

The destructor.

Definition at line 99 of file Event.cc.

References Event::_modGenEvent.

00099                 {
00100     if (_modGenEvent) delete _modGenEvent;
00101   }

Member Function Documentation

const GenEvent & genEvent ( ) const

Return the generated event obtained from an external event generator.

Definition at line 103 of file Event.cc.

References Event::_genEvent, and Event::_modGenEvent.

Referenced by UnstableFinalState::project(), PVertex::project(), InitialQuarks::project(), FinalState::project(), and Beam::project().

00103                                         {
00104     if (_modGenEvent) return *_modGenEvent;
00105     return _genEvent;
00106   }

double weight ( ) const [inline]

The weight associated with the event.

Definition at line 46 of file Event.hh.

References Event::_weight.

Referenced by OPAL_1993_S2692198::analyze(), MC_ZZJETS::analyze(), MC_WWJETS::analyze(), MC_JetAnalysis::analyze(), JADE_OPAL_2000_S4300807::analyze(), D0_2010_S8671338::analyze(), D0_2010_S8566488::analyze(), D0_2009_S8320160::analyze(), D0_2009_S8202443::analyze(), D0_2008_S7863608::analyze(), D0_2008_S7554427::analyze(), D0_2007_S7075677::analyze(), CDF_2008_S8093652::analyze(), BELLE_2006_S6265367::analyze(), and ALEPH_2004_S5765862::analyze().

00046                           {
00047       return _weight;
00048     }

const PROJ& applyProjection ( PROJ & p ) const [inline]

Add a projection p to this Event. If an equivalent Projection has been applied before, the Projection::project(const Event &) of p is not called and a reference to the previous equivalent projection is returned. If no previous Projection was found, the Projection::project(const Event &) of p is called and a reference to p is returned.

Definition at line 60 of file Event.hh.

References Event::_projections, and Projection::project().

Referenced by ProjectionApplier::_applyProjection(), and Event::applyProjection().

00060                                                {
00061       const Projection* cpp(&p);
00062       std::set<const Projection*>::const_iterator old = _projections.find(cpp);
00063       if (old != _projections.end()) {
00064         const Projection& pRef = **old;
00065         return pcast<PROJ>(pRef);
00066       }
00067       // Add the projection via the Projection base class (only
00068       // possible because Event is a friend of Projection)
00069       Projection* pp = const_cast<Projection*>(cpp);
00070       pp->project(*this);
00071       _projections.insert(pp);
00072       return p;
00073     }

const PROJ& applyProjection ( PROJ * pp ) const [inline]

Definition at line 77 of file Event.hh.

References Event::applyProjection().

00077                                                 {
00078       if (!pp) throw Error("Event::applyProjection(PROJ*): Projection pointer is null.");
00079       return applyProjection(*pp);
00080     }

void _geNormAlignment ( ) [private]

Todo:: e+ e- convention? B-factories different from LEP?

Definition at line 26 of file Event.cc.

References Event::_genEvent, Rivet::_geRot180x(), Event::_modGenEvent, Log::getLog(), Rivet::GeV, Log::isActive(), Rivet::make_pdgid_pair(), Rivet::PROTON, and Log::TRACE.

Referenced by Event::Event().

00026                                {
00027     if (!_genEvent.valid_beam_particles()) return;
00028     typedef pair<HepMC::GenParticle*, HepMC::GenParticle*> GPPair;
00029     GPPair bps = _genEvent.beam_particles();
00030     const PdgIdPair beamids = make_pdgid_pair(bps.first->pdg_id(), bps.second->pdg_id());
00031     //Log::getLog("Rivet.Event") << Log::TRACE << "Beam IDs: " << beamids << endl;
00032     const HepMC::GenParticle* plusgp = 0;
00033     bool rot = false;
00034 
00035     // Rotate e+- p and ppbar to put p along +z
00036     /// @todo e+ e- convention? B-factories different from LEP?
00037     // if (compatible(beamids, make_pdgid_pair(ELECTRON, PROTON)) ||
00038     //     compatible(beamids, make_pdgid_pair(POSITRON, PROTON)) ||
00039     //     compatible(beamids, make_pdgid_pair(ANTIPROTON, PROTON)) ) {
00040     //   Log::getLog("Rivet.Event") << Log::TRACE << "May need to rotate event..." << endl;
00041     if (bps.first->pdg_id() != PROTON || bps.second->pdg_id() != PROTON) {
00042       if (bps.first->pdg_id() == PROTON) {
00043         plusgp = bps.first;
00044       } else if (bps.second->pdg_id() == PROTON) {
00045         plusgp = bps.second;
00046       }
00047       if (plusgp && plusgp->momentum().pz() < 0) {
00048         rot = true;
00049       }
00050     }
00051 
00052     // Do the rotation
00053     if (rot) {
00054       if (Log::getLog("Rivet.Event").isActive(Log::TRACE)) {
00055         Log::getLog("Rivet.Event") << Log::TRACE << "Rotating event" << endl;
00056         Log::getLog("Rivet.Event") << Log::TRACE << "Before rotation: "
00057                                    << bps.first->pdg_id() << "@pz=" << bps.first->momentum().pz()/GeV << ", "
00058                                    << bps.second->pdg_id() << "@pz=" << bps.second->momentum().pz()/GeV << endl;
00059       }
00060       if (!_modGenEvent) _modGenEvent = new GenEvent(_genEvent);
00061       _geRot180x(*_modGenEvent);
00062     }
00063   }