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NestedDefsPlugin.cc
//FJSTARTHEADER
// $Id$
//
// Copyright (c) 2007-2021, Matteo Cacciari, Gavin P. Salam and Gregory Soyez
//
//----------------------------------------------------------------------
// This file is part of FastJet.
//
// FastJet is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// The algorithms that underlie FastJet have required considerable
// development. They are described in the original FastJet paper,
// hep-ph/0512210 and in the manual, arXiv:1111.6097. If you use
// FastJet as part of work towards a scientific publication, please
// quote the version you use and include a citation to the manual and
// optionally also to hep-ph/0512210.
//
// FastJet is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with FastJet. If not, see <http://www.gnu.org/licenses/>.
//----------------------------------------------------------------------
//FJENDHEADER
// TODO
// ? Maybe one could provide additional recomb. dists as an "extra".;
// fastjet stuff
#include "fastjet/ClusterSequence.hh"
#include "fastjet/NestedDefsPlugin.hh"
// other stuff
#include <vector>
#include <sstream>
FASTJET_BEGIN_NAMESPACE // defined in fastjet/internal/base.hh
using namespace std;
string NestedDefsPlugin::description () const {
ostringstream desc;
desc << "NestedDefs: successive application of " ;
unsigned int i=1;
for (list<JetDefinition>::const_iterator it=_defs.begin();it!=_defs.end();it++){
desc << "Definition " << i++ << " [" << it->description() << "] - ";
}
return desc.str();
}
void NestedDefsPlugin::run_clustering(ClusterSequence & clust_seq) const {
vector<PseudoJet> momenta;
// build the initial list of particles
momenta = clust_seq.jets();
unsigned int step_n = momenta.size();
// initialise the conversion table, which works as follows
// conversion_table[step_cs_jet_index] = main_cs_jet_index
vector<unsigned int> conversion_table(2*step_n);
vector<unsigned int> new_conversion_table;
for (unsigned int i=0;i<step_n;i++)
conversion_table[i]=i;
// Now the steps go as follows:
// for each definition in the list,
// - do the clustering,
// - copy the history into the main one
// - update the list of momenta and the index conversion table
list<JetDefinition>::const_iterator def_iterator = _defs.begin();
unsigned int def_index=0;
bool last_def=false;
while (def_iterator!=_defs.end()){
last_def = (def_index == (_defs.size()-1));
// do the clustering
ClusterSequence step_cs(momenta, *def_iterator);
// clear the momenta as we shall fill them again
momenta.clear();
new_conversion_table.clear();
// retrieve the history
const vector<ClusterSequence::history_element> & step_history = step_cs.history();
// copy the history
// note that we skip the initial steps which are just the
// declaration of the particles.
vector<ClusterSequence::history_element>::const_iterator
hist_iterator = step_history.begin();
for (unsigned int i=step_n;i!=0;i--)
hist_iterator++;
while (hist_iterator != step_history.end()){
// check if it is a recombination with the beam or a simple recombination
if (hist_iterator->parent2 == ClusterSequence::BeamJet){
// save this jet for future clustering
// unless we've reached the last def in which case, record the clustering
unsigned int step_jet_index = step_cs.history()[hist_iterator->parent1].jetp_index;
if (last_def){
clust_seq.plugin_record_iB_recombination(conversion_table[step_jet_index],
hist_iterator->dij);
} else {
momenta.push_back(step_cs.jets()[step_jet_index]);
new_conversion_table.push_back(conversion_table[step_jet_index]);
}
} else {
// record combination
// note that we set the recombination distance to 0 except for the last alg
unsigned int step_jet1_index = step_cs.history()[hist_iterator->parent1].jetp_index;
unsigned int step_jet2_index = step_cs.history()[hist_iterator->parent2].jetp_index;
PseudoJet newjet = step_cs.jets()[hist_iterator->jetp_index];
int jet_k;
clust_seq.plugin_record_ij_recombination(conversion_table[step_jet1_index],
conversion_table[step_jet2_index],
last_def ? hist_iterator->dij : 0.0,
newjet, jet_k);
// save info in the conversion table for tracking purposes
conversion_table[hist_iterator->jetp_index]=jet_k;
}
// go to the next history element
hist_iterator++;
}
// finalise this step:
// - update nr of particles
// - update conversion table
step_n = momenta.size();
for (unsigned int i=0;i<step_n;i++)
conversion_table[i] = new_conversion_table[i];
// go to the next alg
def_index++;
def_iterator++;
}
}
FASTJET_END_NAMESPACE // defined in fastjet/internal/base.hh
fastjet::ClusterSequence
deals with clustering
Definition ClusterSequence.hh:63
fastjet::ClusterSequence::history
const std::vector< history_element > & history() const
allow the user to access the raw internal history.
Definition ClusterSequence.hh:1007
fastjet::ClusterSequence::plugin_record_iB_recombination
void plugin_record_iB_recombination(int jet_i, double diB)
record the fact that there has been a recombination between jets()[jet_i] and the beam,...
Definition ClusterSequence.hh:343
fastjet::ClusterSequence::jets
const std::vector< PseudoJet > & jets() const
allow the user to access the internally stored _jets() array, which contains both the initial particl...
Definition ClusterSequence.hh:1003
fastjet::ClusterSequence::plugin_record_ij_recombination
void plugin_record_ij_recombination(int jet_i, int jet_j, double dij, int &newjet_k)
record the fact that there has been a recombination between jets()[jet_i] and jets()[jet_k],...
Definition ClusterSequence.hh:326
fastjet::NestedDefsPlugin::description
virtual std::string description() const
return a textual description of the jet-definition implemented in this plugin
Definition NestedDefsPlugin.cc:46
fastjet::NestedDefsPlugin::run_clustering
virtual void run_clustering(ClusterSequence &) const
given a ClusterSequence that has been filled up with initial particles, the following function should...
Definition NestedDefsPlugin.cc:58
fastjet::PseudoJet
Class to contain pseudojets, including minimal information of use to jet-clustering routines.
Definition PseudoJet.hh:68