Rivet::Event Class Reference

Representation of a HepMC event, and enabler of Projection caching. More...

#include <Event.hh>

Public Member Functions
Constructors and destructors.
	Event (GenEvent *ge, const vector< size_t > &weightindices={})
	Event (GenEvent &ge, const vector< size_t > &weightindices={})
	Event (const Event &e)
	Copy constructor.
Major event properties
const GenEvent &	hepmcEvent () const
	The generated HepMC event obtained from an external event generator.
const GenEvent *	hepmcEventPtr () const
	The generated HepMC event pointer obtained from an external event generator.
const GenEvent *	genEvent () const
	The generated HepMC event pointer obtained from an external event generator.
ParticlePair	beams () const
	Get the beam particles.
double	sqrtS () const
	Get the beam centre-of-mass energy.
double	asqrtS () const
	Get the beam centre-of-mass energy per nucleon.
Access to event particles
const Particles &	allParticles () const
	All the raw GenEvent particles, wrapped in Rivet::Particle objects.
Particles	allParticles (const Cut &c) const
	All the raw GenEvent particles, wrapped in Rivet::Particle objects, but with a Cut applied.
template<typename FN >
Particles	allParticles (const FN &f) const
	All the raw GenEvent particles, wrapped in Rivet::Particle objects, but with a selection function applied.
std::valarray< double >	weights () const
	The generation weights associated with the event.
std::vector< std::pair< double, double > >	crossSections () const
	The generation cross-sections associated with the event.
Projection running
template<typename PROJ >
const PROJ &	applyProjection (PROJ &p) const
	Add a projection p to this Event.
template<typename PROJ >
const PROJ &	applyProjection (PROJ *pp) const
	Add a projection p to this Event by pointer.

Detailed Description

Representation of a HepMC event, and enabler of Projection caching.

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 Projection objects which have been applied to the Event so far.

Constructor & Destructor Documentation

Event() [1/2]

Rivet::Event::Event ( GenEvent *  ge, const vector< size_t > &  weightindices = {}  )

inline

Constructor from a HepMC GenEvent pointer

Note

Although Rivet is an analysis system and should not modify the physics of provided events, it needs to ensure that the events are "sane" for analysis purposes, including fixing units and potentially orientations and unphysical graph structures. The passed event pointer is hence not const.

Event() [2/2]

Rivet::Event::Event ( GenEvent &  ge, const vector< size_t > &  weightindices = {}  )

inline

Constructor from a HepMC GenEvent reference

Note

See the pointer-based constructor for discussion of the non-constness of the passed GenEvent.

Deprecated:

HepMC uses pointers, so we should talk to HepMC via pointers: no need to duplicate.

Member Function Documentation

allParticles() [1/2]

Particles Rivet::Event::allParticles ( const Cut &  c ) const

inline

All the raw GenEvent particles, wrapped in Rivet::Particle objects, but with a Cut applied.

Note

Due to the cut, this returns by value, i.e. involves an expensive copy

References allParticles(), and Rivet::select().

allParticles() [2/2]

template<typename FN >

Particles Rivet::Event::allParticles ( const FN &  f ) const

inline

All the raw GenEvent particles, wrapped in Rivet::Particle objects, but with a selection function applied.

Note

Due to the cut, this returns by value, i.e. involves an expensive copy

References allParticles(), and Rivet::select().

applyProjection()

template<typename PROJ >

const PROJ & Rivet::Event::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.

Todo:

Can make this non-templated, since only cares about ptr to Projection base class

Note

Comparisons here are by direct pointer comparison, because equivalence is guaranteed if pointers are equal, and inequivalence guaranteed if they aren't, thanks to the ProjectionHandler registry

Note

Currently using reint cast to integer type to bypass operator==(Proj*, Proj*)

References Rivet::getEnvParam(), MSG_TRACE, and Rivet::Projection::project().

Referenced by applyProjection().

crossSections()

std::vector< std::pair< double, double > > Rivet::Event::crossSections

(

)

const

The generation cross-sections associated with the event.

This vector contains only the cross-sections selected by the AnalysisHandler, so is of constant length for all events.

Note

Excluded cross-sections, and their associated names if set, can be accessed via the GenEvent pointer hepmcEventPtr().

genEvent()

const GenEvent * Rivet::Event::genEvent ( ) const

inline

The generated HepMC event pointer obtained from an external event generator.

Backward-compatibility alias for hepmcEventPtr()

weights()

std::valarray< double > Rivet::Event::weights

(

)

const

The generation weights associated with the event.

This vector contains only the weights selected by the AnalysisHandler, so is of constant length for all events.

Note

Excluded generation weights, and their associated weight names if set, can be accessed via the GenEvent pointer hepmcEventPtr().

Referenced by Rivet::EventMixingBase::project().

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

• /Users/chrisg/software/rivet/include/Rivet/Event.hh