FastJet 3.0.4

base class that sets interface for extensions of ClusterSequence that provide information about the area of each jet More...
#include <fastjet/ClusterSequenceAreaBase.hh>
Public Member Functions  
template<class L >  
ClusterSequenceAreaBase (const std::vector< L > &pseudojets, const JetDefinition &jet_def_in, const bool &writeout_combinations=false)  
a constructor which just carries out the construction of the parent class  
ClusterSequenceAreaBase ()  
default constructor  
virtual  ~ClusterSequenceAreaBase () 
destructor  
virtual double  area (const PseudoJet &) const 
return the area associated with the given jet; this base class returns 0.  
virtual double  area_error (const PseudoJet &) const 
return the error (uncertainty) associated with the determination of the area of this jet; this base class returns 0.  
virtual PseudoJet  area_4vector (const PseudoJet &) const 
return a PseudoJet whose 4vector is defined by the following integral  
virtual bool  is_pure_ghost (const PseudoJet &) const 
true if a jet is made exclusively of ghosts  
virtual bool  has_explicit_ghosts () const 
returns true if ghosts are explicitly included within jets for this ClusterSequence;  
virtual double  empty_area (const Selector &selector) const 
return the total area, corresponding to the given Selector, that is free of jets, in general based on the inclusive jets.  
double  empty_area_from_jets (const std::vector< PseudoJet > &all_jets, const Selector &selector) const 
return the total area, corresponding to the given Selector, that is free of jets, based on the supplied all_jets  
virtual double  n_empty_jets (const Selector &selector) const 
return something similar to the number of pure ghost jets in the given selector's range in an active area case.  
double  median_pt_per_unit_area (const Selector &selector) const 
the median of (pt/area) for jets contained within the selector range, making use also of the info on n_empty_jets  
double  median_pt_per_unit_area_4vector (const Selector &selector) const 
the median of (pt/area_4vector) for jets contained within the selector range, making use also of the info on n_empty_jets  
double  median_pt_per_unit_something (const Selector &selector, bool use_area_4vector) const 
the function that does the work for median_pt_per_unit_area and median_pt_per_unit_area_4vector:  
virtual void  get_median_rho_and_sigma (const Selector &selector, bool use_area_4vector, double &median, double &sigma, double &mean_area) const 
using jets withing the selector range (and with 4vector areas if use_area_4vector), calculate the median pt/area, as well as an "error" (uncertainty), which is defined as the 1sigma halfwidth of the distribution of pt/A, obtained by looking for the point below which we have (10.6827)/2 of the jets (including empty jets).  
virtual void  get_median_rho_and_sigma (const std::vector< PseudoJet > &all_jets, const Selector &selector, bool use_area_4vector, double &median, double &sigma, double &mean_area, bool all_are_inclusive=false) const 
a more advanced version of get_median_rho_and_sigma, which allows one to use any "view" of the event containing all jets (so that, e.g.  
virtual void  get_median_rho_and_sigma (const Selector &selector, bool use_area_4vector, double &median, double &sigma) const 
same as the full version of get_median_rho_and_error, but without access to the mean_area  
virtual void  parabolic_pt_per_unit_area (double &a, double &b, const Selector &selector, double exclude_above=1.0, bool use_area_4vector=false) const 
fits a form pt_per_unit_area(y) = a + b*y^2 in the selector range.  
std::vector< PseudoJet >  subtracted_jets (const double rho, const double ptmin=0.0) const 
return a vector of all subtracted jets, using area_4vector, given rho.  
std::vector< PseudoJet >  subtracted_jets (const Selector &selector, const double ptmin=0.0) const 
return a vector of subtracted jets, using area_4vector.  
PseudoJet  subtracted_jet (const PseudoJet &jet, const double rho) const 
return a subtracted jet, using area_4vector, given rho  
PseudoJet  subtracted_jet (const PseudoJet &jet, const Selector &selector) const 
return a subtracted jet, using area_4vector; note that this is potentially inefficient if repeatedly used for many different jets, because rho will be recalculated each time around.  
double  subtracted_pt (const PseudoJet &jet, const double rho, bool use_area_4vector=false) const 
return the subtracted pt, given rho  
double  subtracted_pt (const PseudoJet &jet, const Selector &selector, bool use_area_4vector=false) const 
return the subtracted pt; note that this is potentially inefficient if repeatedly used for many different jets, because rho will be recalculated each time around.  
Protected Member Functions  
void  _check_selector_good_for_median (const Selector &selector) const 
check the selector is suited for the computations i.e. applies jet by jet and has a finite area 
base class that sets interface for extensions of ClusterSequence that provide information about the area of each jet
the virtual functions here all return 0, since no area determination is implemented.
Definition at line 45 of file ClusterSequenceAreaBase.hh.
virtual double fastjet::ClusterSequenceAreaBase::area  (  const PseudoJet &  )  const [inline, virtual] 
return the area associated with the given jet; this base class returns 0.
Reimplemented in fastjet::ClusterSequenceActiveArea, fastjet::ClusterSequenceActiveAreaExplicitGhosts, fastjet::ClusterSequenceArea, and fastjet::ClusterSequenceVoronoiArea.
Definition at line 67 of file ClusterSequenceAreaBase.hh.
virtual double fastjet::ClusterSequenceAreaBase::area_error  (  const PseudoJet &  )  const [inline, virtual] 
return the error (uncertainty) associated with the determination of the area of this jet; this base class returns 0.
Reimplemented in fastjet::ClusterSequenceActiveArea, fastjet::ClusterSequenceArea, and fastjet::ClusterSequenceVoronoiArea.
Definition at line 71 of file ClusterSequenceAreaBase.hh.
virtual PseudoJet fastjet::ClusterSequenceAreaBase::area_4vector  (  const PseudoJet &  )  const [inline, virtual] 
return a PseudoJet whose 4vector is defined by the following integral
drap d PseudoJet("rap,phi,pt=one") * Theta("rap,phi inside jet boundary")
where PseudoJet("rap,phi,pt=one") is a 4vector with the given rapidity (rap), azimuth (phi) and pt=1, while Theta("rap,phi inside jet boundary") is a function that is 1 when rap,phi define a direction inside the jet boundary and 0 otherwise.
This base class returns a null 4vector.
Reimplemented in fastjet::ClusterSequenceActiveArea, fastjet::ClusterSequenceActiveAreaExplicitGhosts, fastjet::ClusterSequenceArea, and fastjet::ClusterSequenceVoronoiArea.
Definition at line 84 of file ClusterSequenceAreaBase.hh.
virtual bool fastjet::ClusterSequenceAreaBase::is_pure_ghost  (  const PseudoJet &  )  const [inline, virtual] 
true if a jet is made exclusively of ghosts
NB: most area classes do not give any explicit ghost jets, but some do, and they should replace this function with their own version.
Reimplemented in fastjet::ClusterSequenceActiveAreaExplicitGhosts, and fastjet::ClusterSequenceArea.
Definition at line 92 of file ClusterSequenceAreaBase.hh.
virtual bool fastjet::ClusterSequenceAreaBase::has_explicit_ghosts  (  )  const [inline, virtual] 
returns true if ghosts are explicitly included within jets for this ClusterSequence;
Derived classes that do include explicit ghosts should provide an alternative version of this routine and set it properly.
Reimplemented in fastjet::ClusterSequenceActiveAreaExplicitGhosts, and fastjet::ClusterSequenceArea.
Definition at line 101 of file ClusterSequenceAreaBase.hh.
double fastjet::ClusterSequenceAreaBase::empty_area  (  const Selector &  selector  )  const [virtual] 
return the total area, corresponding to the given Selector, that is free of jets, in general based on the inclusive jets.
return the total area, within the selector's range, that is free of jets.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Calculate this as (range area)  {i in range} A_i
for ClusterSequences with explicit ghosts, assume that there will never be any empty area, i.e. it is always filled in by pure ghosts jets. This holds for seq.rec. algorithms
Reimplemented in fastjet::ClusterSequenceActiveArea, fastjet::ClusterSequenceActiveAreaExplicitGhosts, fastjet::ClusterSequenceArea, and fastjet::ClusterSequencePassiveArea.
Definition at line 55 of file ClusterSequenceAreaBase.cc.
double fastjet::ClusterSequenceAreaBase::empty_area_from_jets  (  const std::vector< PseudoJet > &  all_jets, 
const Selector &  selector  
)  const 
return the total area, corresponding to the given Selector, that is free of jets, based on the supplied all_jets
return the total area, within range, that is free of jets.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Calculate this as (range area)  {i in range} A_i
Definition at line 67 of file ClusterSequenceAreaBase.cc.
virtual double fastjet::ClusterSequenceAreaBase::n_empty_jets  (  const Selector &  selector  )  const [inline, virtual] 
return something similar to the number of pure ghost jets in the given selector's range in an active area case.
For the local implementation we return empty_area/(0.55 pi R^2), based on measured properties of ghost jets with kt and cam (cf arXiv:0802.1188).
Note that the number returned is a double.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Reimplemented in fastjet::ClusterSequence1GhostPassiveArea, fastjet::ClusterSequenceActiveArea, and fastjet::ClusterSequenceArea.
Definition at line 133 of file ClusterSequenceAreaBase.hh.
double fastjet::ClusterSequenceAreaBase::median_pt_per_unit_area  (  const Selector &  selector  )  const 
the median of (pt/area) for jets contained within the selector range, making use also of the info on n_empty_jets
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Definition at line 79 of file ClusterSequenceAreaBase.cc.
double fastjet::ClusterSequenceAreaBase::median_pt_per_unit_area_4vector  (  const Selector &  selector  )  const 
the median of (pt/area_4vector) for jets contained within the selector range, making use also of the info on n_empty_jets
The selector passed as an argument has to have a finite area and apply jetbyjet
Definition at line 83 of file ClusterSequenceAreaBase.cc.
double fastjet::ClusterSequenceAreaBase::median_pt_per_unit_something  (  const Selector &  selector, 
bool  use_area_4vector  
)  const 
the function that does the work for median_pt_per_unit_area and median_pt_per_unit_area_4vector:
the median of (pt/area) for jets contained within range, counting the empty area as if it were made up of a collection of empty jets each of area (0.55 * pi R^2).
Definition at line 92 of file ClusterSequenceAreaBase.cc.
void fastjet::ClusterSequenceAreaBase::get_median_rho_and_sigma  (  const Selector &  selector, 
bool  use_area_4vector,  
double &  median,  
double &  sigma,  
double &  mean_area  
)  const [virtual] 
using jets withing the selector range (and with 4vector areas if use_area_4vector), calculate the median pt/area, as well as an "error" (uncertainty), which is defined as the 1sigma halfwidth of the distribution of pt/A, obtained by looking for the point below which we have (10.6827)/2 of the jets (including empty jets).
The subtraction for a jet with uncorrected pt pt^U and area A is
pt^S = pt^U  median*A + sigma*sqrt(A)
where the error is only that associated with the fluctuations in the noise and not that associated with the noise having caused changes in the hardparticle content of the jet.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
NB: subtraction may also be done with 4vector area of course, and this is recommended for jets with larger values of R, as long as rho has also been determined with a 4vector area; using a scalar area causes one to neglect terms of relative order $R^2/8$ in the jet $p_t$.
Reimplemented in fastjet::ClusterSequenceArea.
Definition at line 162 of file ClusterSequenceAreaBase.cc.
virtual void fastjet::ClusterSequenceAreaBase::get_median_rho_and_sigma  (  const std::vector< PseudoJet > &  all_jets, 
const Selector &  selector,  
bool  use_area_4vector,  
double &  median,  
double &  sigma,  
double &  mean_area,  
bool  all_are_inclusive = false 

)  const [virtual] 
a more advanced version of get_median_rho_and_sigma, which allows one to use any "view" of the event containing all jets (so that, e.g.
one might use Cam on a different resolution scale without have to rerun the algorithm).
By default it will assume that "all" are not inclusive jets, so that in dealing with empty area it has to calculate the number of empty jets based on the empty area and the the observed <area> of jets rather than a surmised area
Note that for small effective radii, this can cause problems because the harder jets get an area >> <ghostjetarea> and so the estimate comes out all wrong. In these situations it is highly advisable to use an area with explicit ghosts, since then the "empty" jets are actually visible.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Reimplemented in fastjet::ClusterSequenceArea.
virtual void fastjet::ClusterSequenceAreaBase::get_median_rho_and_sigma  (  const Selector &  selector, 
bool  use_area_4vector,  
double &  median,  
double &  sigma  
)  const [inline, virtual] 
same as the full version of get_median_rho_and_error, but without access to the mean_area
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Reimplemented in fastjet::ClusterSequenceArea.
Definition at line 221 of file ClusterSequenceAreaBase.hh.
void fastjet::ClusterSequenceAreaBase::parabolic_pt_per_unit_area  (  double &  a, 
double &  b,  
const Selector &  selector,  
double  exclude_above = 1.0 , 

bool  use_area_4vector = false 

)  const [virtual] 
fits a form pt_per_unit_area(y) = a + b*y^2 in the selector range.
fits a form pt_per_unit_area(y) = a + b*y^2 for jets in range.
exclude_above allows one to exclude large values of pt/area from fit. (if negative, the cut is discarded) use_area_4vector = true uses the 4vector areas.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
exclude_above allows one to exclude large values of pt/area from fit. use_area_4vector = true uses the 4vector areas.
Reimplemented in fastjet::ClusterSequenceArea.
Definition at line 106 of file ClusterSequenceAreaBase.cc.
vector< PseudoJet > fastjet::ClusterSequenceAreaBase::subtracted_jets  (  const double  rho, 
const double  ptmin = 0.0 

)  const 
return a vector of all subtracted jets, using area_4vector, given rho.
Only inclusive_jets above ptmin are subtracted and returned. the ordering is the same as that of sorted_by_pt(cs.inclusive_jets()), i.e. not necessarily ordered in pt once subtracted
Definition at line 292 of file ClusterSequenceAreaBase.cc.
vector< PseudoJet > fastjet::ClusterSequenceAreaBase::subtracted_jets  (  const Selector &  selector, 
const double  ptmin = 0.0 

)  const 
return a vector of subtracted jets, using area_4vector.
Only inclusive_jets above ptmin are subtracted and returned. the ordering is the same as that of sorted_by_pt(cs.inclusive_jets()), i.e. not necessarily ordered in pt once subtracted
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Only inclusive_jets above ptmin are subtracted and returned. the ordering is the same as that of sorted_by_pt(cs.inclusive_jets()), i.e. not necessarily ordered in pt once subtracted
Definition at line 308 of file ClusterSequenceAreaBase.cc.
PseudoJet fastjet::ClusterSequenceAreaBase::subtracted_jet  (  const PseudoJet &  jet, 
const Selector &  selector  
)  const 
return a subtracted jet, using area_4vector; note that this is potentially inefficient if repeatedly used for many different jets, because rho will be recalculated each time around.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Definition at line 341 of file ClusterSequenceAreaBase.cc.
double fastjet::ClusterSequenceAreaBase::subtracted_pt  (  const PseudoJet &  jet, 
const Selector &  selector,  
bool  use_area_4vector = false 

)  const 
return the subtracted pt; note that this is potentially inefficient if repeatedly used for many different jets, because rho will be recalculated each time around.
The selector passed as an argument has to have a finite area and apply jetbyjet (see the BackgroundEstimator and Subtractor tools for more generic usages)
Definition at line 365 of file ClusterSequenceAreaBase.cc.