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source: git/external/fastjet/tools/Subtractor.hh@ 1f2a49a

ImprovedOutputFile Timing llp
Last change on this file since 1f2a49a was b7b836a, checked in by Pavel Demin <pavel-demin@…>, 6 years ago

update FastJet library to 3.3.1 and FastJet Contrib library to 1.036

  • Property mode set to 100644
File size: 8.3 KB
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[35cdc46]1//FJSTARTHEADER
[b7b836a]2// $Id: Subtractor.hh 4354 2018-04-22 07:12:37Z salam $
[d7d2da3]3//
[b7b836a]4// Copyright (c) 2005-2018, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
[d7d2da3]5//
6//----------------------------------------------------------------------
7// This file is part of FastJet.
8//
9// FastJet is free software; you can redistribute it and/or modify
10// it under the terms of the GNU General Public License as published by
11// the Free Software Foundation; either version 2 of the License, or
12// (at your option) any later version.
13//
14// The algorithms that underlie FastJet have required considerable
[35cdc46]15// development. They are described in the original FastJet paper,
16// hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
[d7d2da3]17// FastJet as part of work towards a scientific publication, please
[35cdc46]18// quote the version you use and include a citation to the manual and
19// optionally also to hep-ph/0512210.
[d7d2da3]20//
21// FastJet is distributed in the hope that it will be useful,
22// but WITHOUT ANY WARRANTY; without even the implied warranty of
23// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24// GNU General Public License for more details.
25//
26// You should have received a copy of the GNU General Public License
27// along with FastJet. If not, see <http://www.gnu.org/licenses/>.
28//----------------------------------------------------------------------
[35cdc46]29//FJENDHEADER
[d7d2da3]30
31#ifndef __FASTJET_TOOLS_SUBTRACTOR_HH__
32#define __FASTJET_TOOLS_SUBTRACTOR_HH__
33
[273e668]34#include "fastjet/internal/base.hh" // namespace macros (include explicitly to help Doxygen)
[d7d2da3]35#include "fastjet/tools/Transformer.hh" // to derive Subtractor from Transformer
36#include "fastjet/tools/BackgroundEstimatorBase.hh" // used as a ctor argument
37
38FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
39
40
41//----------------------------------------------------------------------
42/// @ingroup tools_background
43/// \class Subtractor
44/// Class that helps perform jet background subtraction.
45///
46/// This class derives from Transformer and makes use of a pointer to
47/// a BackgroundEstimatorBase object in order to determine the background
48/// in the vicinity of a given jet and then subtract area*background from
49/// the jet. It can also be initialised with a specific fixed value for the
50/// background pt density.
51///
52/// \section input Input conditions
53///
54/// The original jet must have area support (4-vector)
55///
56/// \section output Output/interface
57///
58/// The underlying structure of the returned, subtracted jet
59/// (i.e. constituents, pieces, etc.) is identical to that of the
60/// original jet.
61///
62class Subtractor : public Transformer{
63public:
64 /// define a subtractor based on a BackgroundEstimator
65 Subtractor(BackgroundEstimatorBase * bge) :
[35cdc46]66 _bge(bge), _rho(-1.0) { set_defaults(); }
[d7d2da3]67
68 /// define a subtractor that uses a fixed value of rho, the background
69 /// pt density per unit area (which must be positive)
70 Subtractor(double rho);
71
[273e668]72 /// define a subtractor that uses a fixed value of rho and rho_m;
73 /// both must be >= 0;
74 Subtractor(double rho, double rho_m);
75
[d7d2da3]76 /// default constructor
[35cdc46]77 Subtractor() : _bge(0), _rho(_invalid_rho) { set_defaults(); }
[d7d2da3]78
79 /// default dtor
80 virtual ~Subtractor(){};
81
[35cdc46]82 /// @name configuring the behaviour
83 //\{
84 //----------------------------------------------------------------
85
86 /// reset all parameters to default values
87 ///
88 /// Note: by default, the rho_m term is not included and the safety
89 /// test for the mass is not done. This is mostly for backwards
90 /// compatibility with FastJet 3.0 and is highly likely to change in
91 /// a future release of FastJet
92 void set_defaults();
93
94 /// when 'use_rho_m' is true, include in the subtraction the
95 /// correction from rho_m, the purely longitudinal,
96 /// particle-mass-induced component of the background density per
97 /// unit area
98 ///
99 /// Note: this will be switched off by default (for backwards
100 /// compatibility with FastJet 3.0) but is highly likely to change
101 /// in a future release of FastJet
102 void set_use_rho_m(bool use_rho_m_in = true){
[273e668]103 if (_bge == 0 && _rho_m < 0) {
104 throw Error("Subtractor: rho_m support works only for Subtractors constructed with a background estimator or an explicit rho_m value");
[35cdc46]105 }
106 _use_rho_m=use_rho_m_in;
107 }
108
109 /// returns whether or not the rho_m component is used
110 bool use_rho_m() const{ return _use_rho_m;}
111
112 /// when 'safe_mass' is true, ensure that the mass of the subtracted
113 /// 4-vector remain positive
114 ///
115 /// when true, if the subtracted mass is negative, we return a
116 /// 4-vector with 0 mass, pt and phi from the subtracted 4-vector
117 /// and the rapidity of the original, unsubtracted jet.
118 ///
119 /// Note: this will be switched off by default (for backwards
120 /// compatibility with FastJet 3.0) but is highly likely to change
121 /// in a future release of FastJet
122 void set_safe_mass(bool safe_mass_in=true){ _safe_mass=safe_mass_in;}
123
124 /// returns whether or not safety tests on the mass are included
125 bool safe_mass() const{ return _safe_mass;}
126
127 /// This is mostly intended for cherge-hadron-subtracted type of
128 /// events where we wich to use vertex information to improve the
129 /// subtraction.
130 ///
131 /// Given the following parameters:
132 /// \param sel_known_vertex selects the particles with a
133 /// known vertex origin
134 /// \param sel_leading_vertex amongst the particles with a
135 /// known vertex origin, select those
136 /// coming from the leading vertex
137 /// Momentum identified as coming from the leading vertex will be
138 /// kept, momentum identified as coming from a non-leading vertex
139 /// will be eliminated and a regular area-median subtraction will be
140 /// applied on the 4-vector sum of the particles with unknown vertex
141 /// origin.
142 ///
143 /// When this is set, we shall ensure that the pt of the subtracted
144 /// 4-vector is at least the pt of the particles that are known to
145 /// come from the leading vertex (if it fails, subtraction returns
146 /// the component that is known to come from the leading vertex ---
147 /// or, the original unsubtracted jet if it contains no particles
148 /// from the leading vertex). Furthermore, when safe_mass() is on, we
149 /// also impose a similar constraint on the mass of the subtracted
150 /// 4-vector (if the test fails, the longitudinal part of the
151 /// subtracted 4-vector is taken from the component that is known to
152 /// come from the leading vertex).
153 void set_known_selectors(const Selector &sel_known_vertex,
154 const Selector &sel_leading_vertex){
155 _sel_known_vertex = sel_known_vertex;
156 _sel_leading_vertex = sel_leading_vertex;
157 }
158
159 //\}
160
161 /// @name description and action
162 //\{
163 //----------------------------------------------------------------
164
[d7d2da3]165 /// returns a jet that's subtracted
166 ///
167 /// \param jet the jet that is to be subtracted
168 /// \return the subtracted jet
169 virtual PseudoJet result(const PseudoJet & jet) const;
170
171 /// class description
172 virtual std::string description() const;
173
[35cdc46]174 //\}
[d7d2da3]175protected:
[35cdc46]176 /// compute the 4-vector that should be subtracted from the given
177 /// jet
178 PseudoJet _amount_to_subtract(const PseudoJet &jet) const;
[d7d2da3]179
180 /// the tool used to estimate the background
181 /// if has to be mutable in case its underlying selector takes a reference jet
182 mutable BackgroundEstimatorBase * _bge;
[273e668]183 /// the fixed value of rho and/or rho_m to use if the user has selected that option
184 double _rho, _rho_m;
[d7d2da3]185
[35cdc46]186 // configuration parameters/flags
187 bool _use_rho_m; ///< include the rho_m correction
188 bool _safe_mass; ///< ensures that the subtracted mass is +ve
189
190 Selector _sel_known_vertex; ///< selects the particles with a
191 ///< known vertex origin
192 Selector _sel_leading_vertex; ///< amongst the particles with a
193 ///< known vertex origin, select those
194 ///< coming from the leading vertex
195
[d7d2da3]196 /// a value of rho that is used as a default to label that the stored
197 /// rho is not valid for subtraction.
198 //
199 // NB: there are two reasons for not having the value written here:
200 // 1) that it caused problems on karnak with g++ 4.0.1 and 2) that
201 // we anyway like -infinity as a default, and since that's a function,
202 // that's not allowed in an include file.
203 static const double _invalid_rho;
[35cdc46]204
[1d208a2]205 static LimitedWarning _unused_rho_m_warning;
[d7d2da3]206};
207
208FASTJET_END_NAMESPACE
209
210#endif // __FASTJET_TOOLS_SUBTRACTOR_HH__
211
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