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source: svn/trunk/Utilities/Fastjet/plugins/CDFCones/CDFMidPointPlugin.hh@ 603

Last change on this file since 603 was 11, checked in by severine ovyn, 16 years ago

Fastjet added; CDFCones directory has been changed

File size: 6.5 KB
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1//STARTHEADER
2// $Id: CDFMidPointPlugin.hh,v 1.1 2008-11-06 14:32:10 ovyn Exp $
3//
4// Copyright (c) 2005-2006, Matteo Cacciari and Gavin Salam
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
15// development and are described in hep-ph/0512210. If you use
16// FastJet as part of work towards a scientific publication, please
17// include a citation to the FastJet paper.
18//
19// FastJet is distributed in the hope that it will be useful,
20// but WITHOUT ANY WARRANTY; without even the implied warranty of
21// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22// GNU General Public License for more details.
23//
24// You should have received a copy of the GNU General Public License
25// along with FastJet; if not, write to the Free Software
26// Foundation, Inc.:
27// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28//----------------------------------------------------------------------
29//ENDHEADER
30
31#ifndef __CDFMIDPOINTPLUGIN_HH__
32#define __CDFMIDPOINTPLUGIN_HH__
33
34#include "Utilities/Fastjet/include/fastjet/JetDefinition.hh"
35
36// questionable whether this should be in fastjet namespace or not...
37
38FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
39
40//----------------------------------------------------------------------
41//
42/// CDFMidPointPlugin is a plugin for fastjet (v2.1 upwards) that
43/// provides an interface to the CDF version of Run-II iterative cone
44/// algorithm with midpoint seeds (also known as the Iterative Legacy
45/// Cone Algorithm, ILCA).
46///
47/// The CDF code has been taken from Joey Huston's webpage
48/// http://www.pa.msu.edu/~huston/Les_Houches_2005/Les_Houches_SM.html
49///
50/// Note that the CDF midpoint code contains options that go beyond
51/// those described in the Tevatron run-II document (hep-ex/0005012),
52/// notably search-cones, as described in hep-ph/0111434, and
53/// midpoints bewteen multiplets of stable cones.
54///
55/// Additionally, the version of the CDF midpoint code distributed
56/// here has been modified by the FastJet authors, so as to allow one
57/// to choose the scale used in the split-merge step.
58//
59//----------------------------------------------------------------------
60class CDFMidPointPlugin : public JetDefinition::Plugin {
61public:
62 /// the choice of scale to be used in the split-merge step
63 // NB: just replicates what we've added to the CDF midpoint code
64 enum SplitMergeScale {SM_pt, SM_Et, SM_mt, SM_pttilde};
65
66 ///
67 /// A CDFMidPointPlugin constructor that looks like the one provided
68 /// by CDF. Its arguments should have the following meaning:
69 ///
70 /// - seed_threshold: minimum pt for a particle to be considered
71 /// a seed of the iteration.
72 ///
73 /// - cone_radius: standard meaning
74 ///
75 /// - cone_area_fraction: stable-cones are searched for with a
76 /// radius Rsearch = R * sqrt(cone_area_fraction), and then
77 /// expanded to size R afterwards; note (hep-ph/0610012) that this
78 /// introduces IR unsafety at NLO for X+2-jet observables (where X
79 /// any hard object).
80 ///
81 /// - max_pair_size: "midpoints" can be added between pairs of
82 /// stable cones, triplets of stable cones, etc.; max_pair_size
83 /// indicates the maximum number of stable cones that are
84 /// assembled when adding midpoints.
85 ///
86 /// - max_iterations: the maximum number of iterations to carry out
87 /// when looking for a stable cone.
88 ///
89 /// - overlap_threshold: if
90 /// (overlapping_Et)/(Et_of_softer_protojet) < overlap_threshold,
91 /// overlapping jets are split, otherwise they are merged.
92 ///
93 /// - sm_scale: a choice for the scale to be used in the split-merge
94 /// step (both for ordering the momenta and quantifying the
95 /// overlap); the three options are
96 ///
97 /// . SM_pt: pt (default -- source of small IR safety issue in purely
98 /// hadronic events)
99 ///
100 /// . SM_Et: Et (not boost invariant, reduces to mt at zero rapidity and
101 /// to pt and infinite rapidity)
102 ///
103 /// . SM_mt: transverse mass = sqrt(m^2+pt^2)
104 ///
105 CDFMidPointPlugin (
106 double seed_threshold ,
107 double cone_radius ,
108 double cone_area_fraction ,
109 int max_pair_size ,
110 int max_iterations ,
111 double overlap_threshold ,
112 SplitMergeScale sm_scale = SM_pt) :
113 _seed_threshold (seed_threshold ),
114 _cone_radius (cone_radius ),
115 _cone_area_fraction (cone_area_fraction ),
116 _max_pair_size (max_pair_size ),
117 _max_iterations (max_iterations ),
118 _overlap_threshold (overlap_threshold ),
119 _sm_scale (sm_scale) {}
120
121 /// a compact constructor
122 CDFMidPointPlugin (double cone_radius,
123 double overlap_threshold = 0.5,
124 double seed_threshold = 1.0,
125 double cone_area_fraction = 1.0) :
126 _seed_threshold (seed_threshold ),
127 _cone_radius (cone_radius ),
128 _cone_area_fraction (cone_area_fraction ),
129 _max_pair_size (2 ),
130 _max_iterations (100 ),
131 _overlap_threshold (overlap_threshold ),
132 _sm_scale (SM_pt) {}
133
134
135 // some functions to return info about parameters
136 double seed_threshold () const {return _seed_threshold ;}
137 double cone_radius () const {return _cone_radius ;}
138 double cone_area_fraction () const {return _cone_area_fraction ;}
139 int max_pair_size () const {return _max_pair_size ;}
140 int max_iterations () const {return _max_iterations ;}
141 double overlap_threshold () const {return _overlap_threshold ;}
142
143
144 // the things that are required by base class
145 virtual std::string description () const;
146 virtual void run_clustering(ClusterSequence &) const;
147 /// the plugin mechanism's standard way of accessing the jet radius
148 virtual double R() const {return cone_radius();}
149
150private:
151
152 double _seed_threshold ;
153 double _cone_radius ;
154 double _cone_area_fraction;
155 int _max_pair_size ;
156 int _max_iterations ;
157 double _overlap_threshold ;
158 SplitMergeScale _sm_scale ;
159};
160
161FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
162
163#endif // __CDFMIDPOINTPLUGIN_HH__
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