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fastjet::BackgroundEstimator Class Reference

#include <BackgroundEstimator.h>

Public Member Functions

 BackgroundEstimator (const ClusterSequenceAreaBase &csa, const RangeDefinition &range)
 
double empty_area ()
 
double mean_area ()
 get the median area of the jets used to actually compute the background properties More...
 
double median_rho ()
 get the median rho More...
 
double n_empty_jets ()
 
unsigned int n_jets_excluded ()
 
unsigned int n_jets_used ()
 get the number of jets used to actually compute the background properties More...
 
void reset ()
 
double rho ()
 synonym for median rho [[do we have this? Both?]] More...
 
void set_excluded_jets (const std::vector< PseudoJet > &excluded_jets)
 
void set_included_jets (const std::vector< PseudoJet > &included_jets, bool all_from_inclusive=true)
 
void set_use_area_4vector (bool use_it=true)
 
double sigma ()
 get the sigma More...
 
 ~BackgroundEstimator ()
 default dtor More...
 

Private Member Functions

void _compute ()
 do the actual job More...
 
void _recompute_if_needed ()
 

Private Attributes

bool _all_from_inclusive
 when true, we'll assume that the incl jets are the complete set More...
 
const ClusterSequenceAreaBase & _csa
 cluster sequence to get jets and areas from More...
 
double _empty_area
 the empty (pure-ghost/unclustered) area! More...
 
std::vector< PseudoJet > _excluded_jets
 jets to be excluded More...
 
std::vector< PseudoJet > _included_jets
 jets to be used More...
 
double _mean_area
 mean area of the jets used to estimate the background More...
 
double _median_rho
 background estimated density per unit area More...
 
double _n_empty_jets
 number of empty (pure-ghost) jets More...
 
unsigned int _n_jets_excluded
 number of jets that have explicitly been excluded More...
 
unsigned int _n_jets_used
 number of jets used to estimate the background More...
 
const RangeDefinition & _range
 range to compute the background in More...
 
double _sigma
 background estimated fluctuations More...
 
bool _uptodate
 true when the background computation is up-to-date More...
 
bool _use_area_4vector
 

Detailed Description

Class to estimate the density of the background per unit area

The default behaviour of this class is to compute the global properties of the background as it is done in ClusterSequenceArea. On top of that, we provide methods to specify an explicit set of jets to use or a list of jets to exclude. We also provide all sorts of additional information regarding the background estimation like the jets that have been used or the number of pure-ghost jets.

Default behaviour: by default the list of included jets is the inclusive jets from the given ClusterSequence; the list of explicitly excluded jets is empty; we use 4-vector area

Beware: by default, to correctly handle partially empty events, the class attempts to calculate an "empty area", based (schematically) on

   range.total_area() - sum_{jets_in_range} jets.area()

For ranges with small areas, this can be innacurate (particularly relevant in dense events where empty_area should be zero and ends up not being zero).

This calculation of empty area can be avoided if you supply a ClusterSequenceArea class with explicit ghosts (ActiveAreaExplicitGhosts). This is recommended!

Definition at line 41 of file BackgroundEstimator.h.

Constructor & Destructor Documentation

◆ BackgroundEstimator()

BackgroundEstimator::BackgroundEstimator ( const ClusterSequenceAreaBase &  csa,
const RangeDefinition &  range 
)

default ctor

Parameters
csathe ClusterSequenceArea to use
rangethe range over which jets will be considered

Definition at line 24 of file BackgroundEstimator.cc.

25  : _csa(csa), _range(range) {
26  reset();
27 }

References reset().

◆ ~BackgroundEstimator()

BackgroundEstimator::~BackgroundEstimator ( )

default dtor

Definition at line 30 of file BackgroundEstimator.cc.

30 {}

Member Function Documentation

◆ _compute()

void BackgroundEstimator::_compute ( )
private

do the actual job

Definition at line 55 of file BackgroundEstimator.cc.

55  {
56  //TODO: check that the alg is OK for median computation
57  //_check_jet_alg_good_for_median();
58 
59  // fill the vector of pt/area with the jets
60  // - in included_jets
61  // - not in excluded_jets
62  // - in the range
63  vector<double> pt_over_areas;
64  double total_area = 0.0;
65 
66  _n_jets_used = 0;
67  _n_jets_excluded = 0;
68 
69  for (unsigned i = 0; i < _included_jets.size(); i++) {
70  const PseudoJet &current_jet = _included_jets[i];
71 
72  // check that the jet is not explicitly excluded
73  // we'll compare them using their cluster_history_index
74  bool excluded = false;
75  int ref_idx = current_jet.cluster_hist_index();
76  for (unsigned int j = 0; j < _excluded_jets.size(); j++)
77  excluded |= (_excluded_jets[j].cluster_hist_index() == ref_idx);
78 
79  // check if the jet is in the range
80  if (_range.is_in_range(current_jet)) {
81  if (excluded) {
82  // keep track of the explicitly excluded jets
84  } else {
85  double this_area = (_use_area_4vector) ? _csa.area_4vector(current_jet).perp() : _csa.area(current_jet);
86 
87  pt_over_areas.push_back(current_jet.perp() / this_area);
88  total_area += this_area;
89  _n_jets_used++;
90  }
91  }
92  }
93 
94  // there is nothing inside our region, so answer will always be zero
95  if (pt_over_areas.empty()) {
96  _median_rho = 0.0;
97  _sigma = 0.0;
98  _mean_area = 0.0;
99  return;
100  }
101 
102  // get median (pt/area) [this is the "old" median definition. It considers
103  // only the "real" jets in calculating the median, i.e. excluding the
104  // only-ghost ones; it will be supplemented with more info below]
105  sort(pt_over_areas.begin(), pt_over_areas.end());
106 
107  // determine the number of empty jets
108  _empty_area = 0.0;
109  _n_empty_jets = 0.0;
110  if (_csa.has_explicit_ghosts()) {
111  _empty_area = 0.0;
112  _n_empty_jets = 0;
113  } else if (_all_from_inclusive) {
114  _empty_area = _csa.empty_area(_range);
115  _n_empty_jets = _csa.n_empty_jets(_range);
116  } else {
117  _empty_area = _csa.empty_area_from_jets(_included_jets, _range);
118  _mean_area = total_area / _n_jets_used; // temporary value
120  }
121 
122  double total_njets = _n_jets_used + _n_empty_jets;
123  total_area += _empty_area;
124 
125  // now get the median & error, accounting for empty jets
126  // define the fractions of distribution at median, median-1sigma
127  double posn[2] = {0.5, (1.0 - 0.6827) / 2.0};
128  double res[2];
129 
130  for (int i = 0; i < 2; i++) {
131  double nj_median_pos = (total_njets - 1) * posn[i] - _n_empty_jets;
132  double nj_median_ratio;
133  if (nj_median_pos >= 0 && pt_over_areas.size() > 1) {
134  int int_nj_median = int(nj_median_pos);
135  nj_median_ratio = pt_over_areas[int_nj_median] * (int_nj_median + 1 - nj_median_pos) +
136  pt_over_areas[int_nj_median + 1] * (nj_median_pos - int_nj_median);
137  } else {
138  nj_median_ratio = 0.0;
139  }
140  res[i] = nj_median_ratio;
141  }
142 
143  // store the results
144  double error = res[0] - res[1];
145  _median_rho = res[0];
146  _mean_area = total_area / total_njets;
148 
149  // record that the computation has been performed
150  _uptodate = true;
151 }

References _all_from_inclusive, _csa, _empty_area, _excluded_jets, _included_jets, _mean_area, _median_rho, _n_empty_jets, _n_jets_excluded, _n_jets_used, _range, _sigma, _uptodate, _use_area_4vector, relativeConstraints::error, mps_fire::i, createfilelist::int, dqmiolumiharvest::j, jetUpdater_cfi::sort, and mathSSE::sqrt().

Referenced by _recompute_if_needed().

◆ _recompute_if_needed()

void fastjet::BackgroundEstimator::_recompute_if_needed ( )
inlineprivate

check if the properties need to be recomputed and do so if needed

Definition at line 141 of file BackgroundEstimator.h.

141  {
142  if (!_uptodate)
143  _compute();
144  _uptodate = true;
145  }

References _compute(), and _uptodate.

Referenced by empty_area(), mean_area(), median_rho(), n_empty_jets(), n_jets_excluded(), n_jets_used(), and sigma().

◆ empty_area()

double fastjet::BackgroundEstimator::empty_area ( )
inline

returns the estimate of the area (within Range) that is not occupied by the jets (excluded jets are removed from this count)

Definition at line 98 of file BackgroundEstimator.h.

98  {
100  return _empty_area;
101  }

References _empty_area, and _recompute_if_needed().

◆ mean_area()

double fastjet::BackgroundEstimator::mean_area ( )
inline

get the median area of the jets used to actually compute the background properties

Definition at line 70 of file BackgroundEstimator.h.

70  {
72  return _mean_area;
73  }

References _mean_area, and _recompute_if_needed().

◆ median_rho()

double fastjet::BackgroundEstimator::median_rho ( )
inline

get the median rho

Definition at line 55 of file BackgroundEstimator.h.

55  {
57  return _median_rho;
58  }

References _median_rho, and _recompute_if_needed().

Referenced by rho().

◆ n_empty_jets()

double fastjet::BackgroundEstimator::n_empty_jets ( )
inline

get the number of empty jets used when computing the background properties; (it is deduced from the empty area with an assumption about the average area of jets)

Definition at line 91 of file BackgroundEstimator.h.

91  {
93  return _n_empty_jets;
94  }

References _n_empty_jets, and _recompute_if_needed().

◆ n_jets_excluded()

unsigned int fastjet::BackgroundEstimator::n_jets_excluded ( )
inline

get the number of jets (within the given range) that have been explicitly excluded when computing the background properties

Definition at line 83 of file BackgroundEstimator.h.

83  {
85  return _n_jets_excluded;
86  }

References _n_jets_excluded, and _recompute_if_needed().

◆ n_jets_used()

unsigned int fastjet::BackgroundEstimator::n_jets_used ( )
inline

get the number of jets used to actually compute the background properties

Definition at line 76 of file BackgroundEstimator.h.

76  {
78  return _n_jets_used;
79  }

References _n_jets_used, and _recompute_if_needed().

◆ reset()

void BackgroundEstimator::reset ( void  )

reset to default values set the list of included jets to the inclusive jets and clear the excluded ones

Definition at line 34 of file BackgroundEstimator.cc.

34  {
35  // set the list of included jets to the inclusive jets
36  _included_jets = _csa.inclusive_jets();
37  _all_from_inclusive = true;
38  //set_included_jets(_csa.inclusive_jets());
39 
40  // clear the list of explicitly excluded jets
41  _excluded_jets.clear();
42  //set_excluded_jets(vector<PseudoJet>());
43 
44  // set the remaining default parameters
45  set_use_area_4vector(); // true by default
46 
47  // reset the computed values
48  _median_rho = _sigma = _mean_area = 0.0;
50  _empty_area = 0.0;
51  _uptodate = false;
52 }

References _all_from_inclusive, _csa, _empty_area, _excluded_jets, _included_jets, _mean_area, _median_rho, _n_empty_jets, _n_jets_excluded, _n_jets_used, _sigma, _uptodate, and set_use_area_4vector().

Referenced by BackgroundEstimator().

◆ rho()

double fastjet::BackgroundEstimator::rho ( )
inline

synonym for median rho [[do we have this? Both?]]

Definition at line 61 of file BackgroundEstimator.h.

61 { return median_rho(); }

References median_rho().

Referenced by Lepton.Lepton::absIsoFromEA(), Muon.Muon::absIsoWithFSR(), and VirtualJetProducer::writeJets().

◆ set_excluded_jets()

void fastjet::BackgroundEstimator::set_excluded_jets ( const std::vector< PseudoJet > &  excluded_jets)
inline

set the list of explicitly excluded jets

Parameters
excluded_jetsthe list of jets that have to be explicitly excluded

Definition at line 130 of file BackgroundEstimator.h.

130  {
131  _excluded_jets = excluded_jets;
132  _uptodate = false;
133  }

References _excluded_jets, and _uptodate.

Referenced by VirtualJetProducer::writeJets().

◆ set_included_jets()

void fastjet::BackgroundEstimator::set_included_jets ( const std::vector< PseudoJet > &  included_jets,
bool  all_from_inclusive = true 
)
inline

set the list of included jets

Parameters
included_jetsthe list of jets to include
all_from_includedwhen true, we'll assume that the cluster sequence inclusive jets give all the potential jets in the range. In practice this means that the empty area will be computed from the inclusive jets rather than from the 'included_jets'. You can overwrite the default value and send it to 'false' e.g. when the included_jets you provide are themselves a list of inclusive jets.

Definition at line 122 of file BackgroundEstimator.h.

122  {
123  _included_jets = included_jets;
124  _all_from_inclusive = all_from_inclusive;
125  _uptodate = false;
126  }

References _all_from_inclusive, _included_jets, and _uptodate.

◆ set_use_area_4vector()

void fastjet::BackgroundEstimator::set_use_area_4vector ( bool  use_it = true)
inline

specify if one uses the scalar or 4-vector area

Parameters
use_itwhether one uses the 4-vector area or not (true by default)

Definition at line 112 of file BackgroundEstimator.h.

112 { _use_area_4vector = use_it; }

References _use_area_4vector.

Referenced by reset().

◆ sigma()

double fastjet::BackgroundEstimator::sigma ( )
inline

get the sigma

Definition at line 64 of file BackgroundEstimator.h.

64  {
66  return _sigma;
67  }

References _recompute_if_needed(), and _sigma.

Referenced by VirtualJetProducer::writeJets().

Member Data Documentation

◆ _all_from_inclusive

bool fastjet::BackgroundEstimator::_all_from_inclusive
private

when true, we'll assume that the incl jets are the complete set

Definition at line 152 of file BackgroundEstimator.h.

Referenced by _compute(), reset(), and set_included_jets().

◆ _csa

const ClusterSequenceAreaBase& fastjet::BackgroundEstimator::_csa
private

cluster sequence to get jets and areas from

Definition at line 148 of file BackgroundEstimator.h.

Referenced by _compute(), and reset().

◆ _empty_area

double fastjet::BackgroundEstimator::_empty_area
private

the empty (pure-ghost/unclustered) area!

Definition at line 162 of file BackgroundEstimator.h.

Referenced by _compute(), empty_area(), and reset().

◆ _excluded_jets

std::vector<PseudoJet> fastjet::BackgroundEstimator::_excluded_jets
private

jets to be excluded

Definition at line 151 of file BackgroundEstimator.h.

Referenced by _compute(), reset(), and set_excluded_jets().

◆ _included_jets

std::vector<PseudoJet> fastjet::BackgroundEstimator::_included_jets
private

jets to be used

Definition at line 150 of file BackgroundEstimator.h.

Referenced by _compute(), reset(), and set_included_jets().

◆ _mean_area

double fastjet::BackgroundEstimator::_mean_area
private

mean area of the jets used to estimate the background

Definition at line 158 of file BackgroundEstimator.h.

Referenced by _compute(), mean_area(), and reset().

◆ _median_rho

double fastjet::BackgroundEstimator::_median_rho
private

background estimated density per unit area

Definition at line 156 of file BackgroundEstimator.h.

Referenced by _compute(), median_rho(), and reset().

◆ _n_empty_jets

double fastjet::BackgroundEstimator::_n_empty_jets
private

number of empty (pure-ghost) jets

Definition at line 161 of file BackgroundEstimator.h.

Referenced by _compute(), n_empty_jets(), and reset().

◆ _n_jets_excluded

unsigned int fastjet::BackgroundEstimator::_n_jets_excluded
private

number of jets that have explicitly been excluded

Definition at line 160 of file BackgroundEstimator.h.

Referenced by _compute(), n_jets_excluded(), and reset().

◆ _n_jets_used

unsigned int fastjet::BackgroundEstimator::_n_jets_used
private

number of jets used to estimate the background

Definition at line 159 of file BackgroundEstimator.h.

Referenced by _compute(), n_jets_used(), and reset().

◆ _range

const RangeDefinition& fastjet::BackgroundEstimator::_range
private

range to compute the background in

Definition at line 149 of file BackgroundEstimator.h.

Referenced by _compute().

◆ _sigma

double fastjet::BackgroundEstimator::_sigma
private

background estimated fluctuations

Definition at line 157 of file BackgroundEstimator.h.

Referenced by _compute(), reset(), and sigma().

◆ _uptodate

bool fastjet::BackgroundEstimator::_uptodate
private

true when the background computation is up-to-date

Definition at line 165 of file BackgroundEstimator.h.

Referenced by _compute(), _recompute_if_needed(), reset(), set_excluded_jets(), and set_included_jets().

◆ _use_area_4vector

bool fastjet::BackgroundEstimator::_use_area_4vector
private

Definition at line 153 of file BackgroundEstimator.h.

Referenced by _compute(), and set_use_area_4vector().

FastTimerService_cff.range
range
Definition: FastTimerService_cff.py:34
mps_fire.i
i
Definition: mps_fire.py:428
fastjet::BackgroundEstimator::_n_jets_used
unsigned int _n_jets_used
number of jets used to estimate the background
Definition: BackgroundEstimator.h:159
fastjet::BackgroundEstimator::_sigma
double _sigma
background estimated fluctuations
Definition: BackgroundEstimator.h:157
fastjet::BackgroundEstimator::set_use_area_4vector
void set_use_area_4vector(bool use_it=true)
Definition: BackgroundEstimator.h:112
fastjet::BackgroundEstimator::_use_area_4vector
bool _use_area_4vector
Definition: BackgroundEstimator.h:153
fastjet::BackgroundEstimator::_median_rho
double _median_rho
background estimated density per unit area
Definition: BackgroundEstimator.h:156
relativeConstraints.error
error
Definition: relativeConstraints.py:53
fastjet::BackgroundEstimator::_csa
const ClusterSequenceAreaBase & _csa
cluster sequence to get jets and areas from
Definition: BackgroundEstimator.h:148
fastjet::BackgroundEstimator::_excluded_jets
std::vector< PseudoJet > _excluded_jets
jets to be excluded
Definition: BackgroundEstimator.h:151
fastjet::BackgroundEstimator::_all_from_inclusive
bool _all_from_inclusive
when true, we'll assume that the incl jets are the complete set
Definition: BackgroundEstimator.h:152
mathSSE::sqrt
T sqrt(T t)
Definition: SSEVec.h:19
fastjet::BackgroundEstimator::_recompute_if_needed
void _recompute_if_needed()
Definition: BackgroundEstimator.h:141
fastjet::BackgroundEstimator::_compute
void _compute()
do the actual job
Definition: BackgroundEstimator.cc:55
fastjet::BackgroundEstimator::_included_jets
std::vector< PseudoJet > _included_jets
jets to be used
Definition: BackgroundEstimator.h:150
fastjet::BackgroundEstimator::reset
void reset()
Definition: BackgroundEstimator.cc:34
jetUpdater_cfi.sort
sort
Definition: jetUpdater_cfi.py:29
fastjet::BackgroundEstimator::_range
const RangeDefinition & _range
range to compute the background in
Definition: BackgroundEstimator.h:149
createfilelist.int
int
Definition: createfilelist.py:10
fastjet::BackgroundEstimator::_n_jets_excluded
unsigned int _n_jets_excluded
number of jets that have explicitly been excluded
Definition: BackgroundEstimator.h:160
fastjet::BackgroundEstimator::median_rho
double median_rho()
get the median rho
Definition: BackgroundEstimator.h:55
fastjet::BackgroundEstimator::_n_empty_jets
double _n_empty_jets
number of empty (pure-ghost) jets
Definition: BackgroundEstimator.h:161
res
Definition: Electron.h:6
fastjet::BackgroundEstimator::_empty_area
double _empty_area
the empty (pure-ghost/unclustered) area!
Definition: BackgroundEstimator.h:162
fastjet::BackgroundEstimator::_uptodate
bool _uptodate
true when the background computation is up-to-date
Definition: BackgroundEstimator.h:165
dqmiolumiharvest.j
j
Definition: dqmiolumiharvest.py:66
fastjet::BackgroundEstimator::_mean_area
double _mean_area
mean area of the jets used to estimate the background
Definition: BackgroundEstimator.h:158