fastjet_subjets.cc File Reference

#include "fastjet/PseudoJet.hh"
#include "fastjet/ClusterSequence.hh"
#include <iostream>
#include <sstream>
#include <vector>

Include dependency graph for fastjet_subjets.cc:

Go to the source code of this file.

Functions
void	print_jets (const fj::ClusterSequence &clust_seq, const vector< fj::PseudoJet > &jets)
	a function that pretty prints a list of jets
void	print_jet (const fj::ClusterSequence &clust_seq, const fj::PseudoJet &jet)
	print a single jet
void	print_jets_and_sub (const fj::ClusterSequence &clust_seq, const vector< fj::PseudoJet > &jets, double dcut)
	a function that pretty prints a list of jets
int	main (int argc, char **argv)
	an example program showing how to use fastjet

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Function Documentation

int main	(	int	argc,
		char **	argv
	)

an example program showing how to use fastjet

Definition at line 69 of file fastjet_subjets.cc.

References fastjet::cambridge_algorithm, fastjet::JetDefinition::description(), fastjet::ClusterSequence::exclusive_jets(), fastjet::ClusterSequence::inclusive_jets(), print_jets(), print_jets_and_sub(), and fastjet::ClusterSequence::strategy_string().

                                  {
  
  vector<fj::PseudoJet> input_particles;
  
  // read in input particles
  double px, py , pz, E;
  while (cin >> px >> py >> pz >> E) {
    // create a fj::PseudoJet with these components and put it onto
    // back of the input_particles vector
    input_particles.push_back(fj::PseudoJet(px,py,pz,E)); 
  }
  
  // We'll do two subjet analyses, physically rather different
  double R = 1.0;
  //fj::JetDefinition kt_def(fj::kt_algorithm, R);
  fj::JetDefinition cam_def(fj::cambridge_algorithm, R);

  // run the jet clustering with the above jet definition
  //fj::ClusterSequence kt_seq(input_particles, kt_def);
  fj::ClusterSequence cam_seq(input_particles, cam_def);

  // tell the user what was done
  cout << "Ran " << cam_def.description() << endl;
  cout << "Strategy adopted by FastJet was "<<
       cam_seq.strategy_string()<<endl<<endl;

  // extract the inclusive jets with pt > 5 GeV
  double ptmin = 5.0;
  vector<fj::PseudoJet> inclusive_jets = cam_seq.inclusive_jets(ptmin);

  // for the subjets  
  double smallR = 0.4;
  double dcut_cam = pow(smallR/R,2);

  // print them out
  cout << "Printing inclusive jets (R = "<<R<<") with pt > "<< ptmin<<" GeV\n";
  cout << "and their subjets with smallR = " << smallR << "\n";
  cout << "---------------------------------------\n";
  print_jets_and_sub(cam_seq, inclusive_jets, dcut_cam);
  cout << endl;


  // print them out
  vector<fj::PseudoJet> exclusive_jets = cam_seq.exclusive_jets(dcut_cam);
  cout << "Printing exclusive jets with dcut = "<< dcut_cam<<" \n";
  cout << "--------------------------------------------\n";
  print_jets(cam_seq, exclusive_jets);


}

void print_jet	(	const fj::ClusterSequence &	clust_seq,
		const fj::PseudoJet &	jet
	)

print a single jet

Definition at line 172 of file fastjet_subjets.cc.

References fastjet::ClusterSequence::constituents(), fastjet::PseudoJet::perp(), fastjet::PseudoJet::phi(), and fastjet::PseudoJet::rap().

Referenced by print_jets(), and print_jets_and_sub().

                                         {
  int n_constituents = clust_seq.constituents(jet).size();
  printf("%15.8f %15.8f %15.8f %8u\n",
         jet.rap(), jet.phi(), jet.perp(), n_constituents);
}

void print_jets	(	const fj::ClusterSequence &	clust_seq,
		const vector< fj::PseudoJet > &	jets
	)

a function that pretty prints a list of jets

Definition at line 123 of file fastjet_subjets.cc.

References print_jet(), and fastjet::sorted_by_pt().

                                                   {

  // sort jets into increasing pt
  vector<fj::PseudoJet> sorted_jets = sorted_by_pt(jets);  

  // label the columns
  printf("%5s %15s %15s %15s %15s\n","jet #", "rapidity", 
         "phi", "pt", "n constituents");
  
  // print out the details for each jet
  for (unsigned int i = 0; i < sorted_jets.size(); i++) {
    printf("%5u ",i);
    print_jet(clust_seq, sorted_jets[i]);
  }

}

void print_jets_and_sub	(	const fj::ClusterSequence &	clust_seq,
		const vector< fj::PseudoJet > &	jets,
		double	dcut
	)

a function that pretty prints a list of jets

Definition at line 144 of file fastjet_subjets.cc.

References fastjet::ClusterSequence::exclusive_subjets(), print_jet(), and fastjet::sorted_by_pt().

Referenced by main().

                                      {

  // sort jets into increasing pt
  vector<fj::PseudoJet> sorted_jets = sorted_by_pt(jets);  

  // label the columns
  printf("%5s %15s %15s %15s %15s\n","jet #", "rapidity", 
         "phi", "pt", "n constituents");
  
  // print out the details for each jet
  for (unsigned int i = 0; i < sorted_jets.size(); i++) {
    printf("%5u       ",i);
    print_jet(clust_seq, sorted_jets[i]);
    vector<fj::PseudoJet> subjets = 
      sorted_by_pt(clust_seq.exclusive_subjets(sorted_jets[i], dcut));
    for (unsigned int j = 0; j < subjets.size(); j++) {
      printf("    -sub-%02u ",j);
      print_jet(clust_seq, subjets[j]);
    }
  }

}