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source: git/external/fastjet/ClusterSequence_N2.cc@ b1fd38d

ImprovedOutputFile Timing dual_readout llp
Last change on this file since b1fd38d was 35cdc46, checked in by Pavel Demin <demin@…>, 10 years ago

upgrade FastJet to version 3.1.0-beta.1, upgrade Nsubjettiness to version 2.1.0, add SoftKiller version 1.0.0

  • Property mode set to 100644
File size: 4.4 KB
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1//FJSTARTHEADER
2// $Id: ClusterSequence_N2.cc 3433 2014-07-23 08:17:03Z salam $
3//
4// Copyright (c) 2005-2014, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
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. They are described in the original FastJet paper,
16// hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
17// FastJet as part of work towards a scientific publication, please
18// quote the version you use and include a citation to the manual and
19// optionally also to hep-ph/0512210.
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//----------------------------------------------------------------------
29//FJENDHEADER
30
31
32// The plain N^2 part of the ClusterSequence class -- separated out
33// from the rest of the class implementation so as to speed up
34// compilation of this particular part while it is under test.
35
36#include "fastjet/internal/ClusterSequence_N2.icc"
37
38#include<iostream>
39
40FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
41
42
43using namespace std;
44
45
46//*************************************************************************
47//
48// THINGS FOR E+E-
49//
50//*************************************************************************
51
52
53//----------------------------------------------------------------------
54template<> inline void ClusterSequence::_bj_set_jetinfo(
55 EEBriefJet * const jetA, const int _jets_index) const {
56
57 double E = _jets[_jets_index].E();
58 double scale = E*E; // the default energy scale for the kt alg
59 double p = jet_def().extra_param(); // in case we're ee_genkt
60 switch (_jet_algorithm) {
61 case ee_kt_algorithm:
62 assert(_Rparam > 2.0); // force this to be true! [not best place, but works]
63 // recall that _invR2 is artificially set to 1 for this alg
64 // so that we automatically have dij = scale * 2(1-cos theta_ij)
65 // Normally, _Rparam should be automatically set to 4 from JetDefinition
66 break;
67 case ee_genkt_algorithm:
68 if (p <= 0 && scale < 1e-300) scale = 1e-300; // same dodgy safety as genkt
69 scale = pow(scale,p);
70 break;
71 default:
72 throw Error("Unrecognised jet algorithm");
73 }
74 jetA->kt2 = scale; // "kt2" might one day be renamed as "scale" or some such
75
76 double norm = _jets[_jets_index].modp2();
77 if (norm > 0) {
78 norm = 1.0/sqrt(norm);
79 jetA->nx = norm * _jets[_jets_index].px();
80 jetA->ny = norm * _jets[_jets_index].py();
81 jetA->nz = norm * _jets[_jets_index].pz();
82 } else {
83 jetA->nx = 0.0;
84 jetA->ny = 0.0;
85 jetA->nz = 1.0;
86 }
87 jetA->_jets_index = _jets_index;
88 // initialise NN info as well
89 jetA->NN_dist = _R2;
90 jetA->NN = NULL;
91}
92
93//----------------------------------------------------------------------
94// returns the angular distance between the two jets
95template<> double ClusterSequence::_bj_dist(
96 const EEBriefJet * const jeta,
97 const EEBriefJet * const jetb) const {
98 double dist = 1.0
99 - jeta->nx*jetb->nx
100 - jeta->ny*jetb->ny
101 - jeta->nz*jetb->nz;
102 dist *= 2; // distance is _2_*min(Ei^2,Ej^2)*(1-cos theta)
103 return dist;
104}
105
106
107
108// get explicit copies of the two N2 cluster cases we need
109// plain BriefJet
110void ClusterSequence::_simple_N2_cluster_BriefJet() {
111 _simple_N2_cluster<BriefJet>();
112}
113
114
115// e+e- BriefJet
116void ClusterSequence::_simple_N2_cluster_EEBriefJet() {
117 _simple_N2_cluster<EEBriefJet>();
118}
119
120// //----------------------------------------------------------------------
121// /// Force instantiation of desired versions of _simple_N2_cluster
122// ///
123// /// This is not very elegant...
124// void ClusterSequence::_dummy_N2_cluster_instantiation() {
125// _simple_N2_cluster<BriefJet>();
126// _simple_N2_cluster<EEBriefJet>();
127// }
128
129FASTJET_END_NAMESPACE
130
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