HepMC3 event record library
Public Types | Public Member Functions | Protected Member Functions | Protected Attributes
GenericFeature< Feature_type > Class Template Reference

Detailed Description

template<typename Feature_type>
class HepMC3::GenericFeature< Feature_type >

GenericFeature defines the Feature interface GenericFeature is not intended to be used directly. The derived Feature class and its specialisations should be used.

A Feature wraps a function object that can extract a generic Feature_type from a ConstGenParticlePtr. Usually the Feature_type would be something like int (e.g. status) or double (e.g. pT), but it could in principle be any attribute of a particle so long as there are well defined <, <=, >, >=, == and != operators for that attribute, as well as an abs function.

Once a Feature is defined, you can obtain Filters that select Particles according to that Feature by e.g. Feature<int> status([](ConstGenParticlePtr p)->int{return p->status();}); bool is_stable = (status == 1)(p); Filter is_beam = (status == 4); bool beam = is_beam(p);

An abs function is also defined, so abs(Feature) works as you'd expect, e.g. Feature<double> rapidity([](ConstGenParticlePtr p)->double{return p->momentum().rap();}); Filter rapCut = abs(rapidity) < 2.5;

Please also see the Selector interface, which defines an abstract interface to Feature that is free of the template params and also includes some standard Features such as

Selector::STATUS; Selector::PDG_ID; Selector::PT; Selector::RAPIDITY;

Definition at line 59 of file Feature.h.

#include <Feature.h>

+ Inheritance diagram for GenericFeature< Feature_type >:
+ Collaboration diagram for GenericFeature< Feature_type >:

Public Types

using Evaluator_type = std::function< Feature_type(ConstGenParticlePtr)>
 evaluator type
 
using EvaluatorPtr = std::shared_ptr< Evaluator_type >
 shared pointer for evaluator type
 

Public Member Functions

Feature_type operator() (ConstGenParticlePtr input) const
 access the underlying feature value
 
Filter operator> (Feature_type value) const
 greater than operator
 
Filter operator< (Feature_type value) const
 less than operator
 
Filter operator>= (Feature_type value) const
 greater than or equals operator
 
Filter operator<= (Feature_type value) const
 less than or equals operator
 
virtual Filter operator== (Feature_type value) const
 equality operator
 
virtual Filter operator!= (Feature_type value) const
 inequality operator
 

Protected Member Functions

 GenericFeature (Evaluator_type functor)
 Hide the constructor so no one can use GenericFeature directly.
 
 GenericFeature (const GenericFeature &copy)
 Hide the copy constructor.
 

Protected Attributes

EvaluatorPtr m_internal
 internal copy of func for evaluation on the heap so will persist in resulting Filters even if parent Feature object was destroyed
 

Member Typedef Documentation

◆ Evaluator_type

using Evaluator_type = std::function<Feature_type(ConstGenParticlePtr)>

evaluator type

Definition at line 62 of file Feature.h.

◆ EvaluatorPtr

using EvaluatorPtr = std::shared_ptr<Evaluator_type>

shared pointer for evaluator type

Definition at line 64 of file Feature.h.

Constructor & Destructor Documentation

◆ GenericFeature() [1/2]

GenericFeature ( Evaluator_type  functor)
inlineprotected

Hide the constructor so no one can use GenericFeature directly.

Definition at line 114 of file Feature.h.

◆ GenericFeature() [2/2]

GenericFeature ( const GenericFeature< Feature_type > &  copy)
inlineprotected

Hide the copy constructor.

Definition at line 117 of file Feature.h.

Member Function Documentation

◆ operator!=()

virtual Filter operator!= ( Feature_type  value) const
inlinevirtual

◆ operator()()

Feature_type operator() ( ConstGenParticlePtr  input) const
inline

access the underlying feature value

Definition at line 67 of file Feature.h.

References GenericFeature< Feature_type >::m_internal.

◆ operator<()

Filter operator< ( Feature_type  value) const
inline

less than operator

Returns
Filter function

Definition at line 79 of file Feature.h.

References GenericFeature< Feature_type >::m_internal.

◆ operator<=()

Filter operator<= ( Feature_type  value) const
inline

less than or equals operator

Returns
Filter function

Definition at line 93 of file Feature.h.

References GenericFeature< Feature_type >::m_internal.

◆ operator==()

virtual Filter operator== ( Feature_type  value) const
inlinevirtual

◆ operator>()

Filter operator> ( Feature_type  value) const
inline

greater than operator

Returns
Filter function

Definition at line 73 of file Feature.h.

References GenericFeature< Feature_type >::m_internal.

◆ operator>=()

Filter operator>= ( Feature_type  value) const
inline

greater than or equals operator

Returns
Filter function

Definition at line 86 of file Feature.h.

References GenericFeature< Feature_type >::m_internal.

Field Documentation

◆ m_internal

EvaluatorPtr m_internal
protected

internal copy of func for evaluation on the heap so will persist in resulting Filters even if parent Feature object was destroyed

Definition at line 122 of file Feature.h.


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