fastjet_timing.cc File Reference

#include "fastjet/PseudoJet.hh"
#include "fastjet/ClusterSequence.hh"
#include <iostream>
#include <sstream>
#include <valarray>
#include <vector>
#include <cstdlib>
#include <cstddef>
#include "CmdLine.hh"

Include dependency graph for fastjet_timing.cc:

Go to the source code of this file.

Functions
double	pow2 (const double x)
int	main (int argc, char **argv)
	a program to test and time the kt algorithm as implemented in fastjet

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Function Documentation

int main	(	int	argc,
		char **	argv
	)

a program to test and time the kt algorithm as implemented in fastjet

Definition at line 98 of file fastjet_timing.cc.

References CmdLine::all_options_used(), Best, fastjet::cambridge_algorithm, CmdLine::double_val(), CmdLine::int_val(), fastjet::kt_algorithm, pow2(), CmdLine::present(), fastjet::PseudoJet::rap(), fastjet::sorted_by_E(), fastjet::sorted_by_pt(), fastjet::ClusterSequence::strategy_string(), and twopi.

                                  {

  CmdLine cmdline(argc,argv);
  // allow the use to specify the fj::Strategy either through the
  // -clever or the -strategy options (both will take numerical
  // values); the latter will override the former.
  fj::Strategy  strategy  = fj::Strategy(cmdline.int_val("-strategy",
                                        cmdline.int_val("-clever", fj::Best)));
  int  repeat  = cmdline.int_val("-repeat",1);
  int  combine = cmdline.int_val("-combine",1);
  bool write   = cmdline.present("-write");
  bool unique_write = cmdline.present("-unique_write");
  bool hydjet  = cmdline.present("-hydjet");
  double ktR   = cmdline.double_val("-r",1.0);
  double inclkt = cmdline.double_val("-incl",-1.0);
  int    excln  = cmdline.int_val   ("-excln",-1);
  double excld  = cmdline.double_val("-excld",-1.0);
  double etamax = cmdline.double_val("-etamax",1.0e305);
  bool   show_constituents = cmdline.present("-const");
  bool   massless = cmdline.present("-massless");
  int  nev     = cmdline.int_val("-nev",1);
  bool add_dense_coverage = cmdline.present("-dense");

  // The following option causes the Cambridge algo to be used.
  // Note that currently the only output that works sensibly here is
  // "-incl 0"
  fj::JetAlgorithm jet_algorithm;
  if (cmdline.present("-cam")) {
    jet_algorithm = fj::cambridge_algorithm;
  } else {
    jet_algorithm = fj::kt_algorithm;
  }

  if (!cmdline.all_options_used()) {cerr << 
      "Error: some options were not recognized"<<endl; 
    exit(-1);}


  for (int iev = 0; iev < nev; iev++) {
  vector<fj::PseudoJet> jets;
  string line;
  int  ndone = 0;
  while (getline(cin, line)) {
      //cout << line<<endl;
    istringstream linestream(line);
    if (line == "#END") {
      ndone += 1;
      if (ndone == combine) {break;}
    }
    if (line.substr(0,1) == "#") {continue;}
    valarray<double> fourvec(4);
    if (hydjet) {
      // special reading from hydjet.txt event record (though actually
      // this is supposed to be a standard pythia event record, so
      // being able to read from it is perhaps not so bad an idea...)
      int ii, istat,id,m1,m2,d1,d2;
      double mass;
      linestream >> ii>> istat >> id >> m1 >> m2 >> d1 >> d2
                 >> fourvec[0] >> fourvec[1] >> fourvec[2] >> mass;
      // current file contains mass of particle as 4th entry
      if (istat == 1) {
        fourvec[3] = sqrt(+pow2(fourvec[0])+pow2(fourvec[1])
                          +pow2(fourvec[2])+pow2(mass));
      }
    } else {
      if (massless) {
        linestream >> fourvec[0] >> fourvec[1] >> fourvec[2];
        fourvec[3] = sqrt(pow2(fourvec[0])+pow2(fourvec[1])+pow2(fourvec[2]));}
      else {
        linestream >> fourvec[0] >> fourvec[1] >> fourvec[2] >> fourvec[3];
      }
    }
    fj::PseudoJet psjet(fourvec);
    if (abs(psjet.rap() < etamax)) {jets.push_back(psjet);}
  }

  // add a fake underlying event which is very soft, uniformly distributed
  // in eta,phi so as to allow one to reconstruct the area that is associated
  // with each jet.
  if (add_dense_coverage) {
    srand(2);
    int nphi = 60;
    int neta = 100;
    double kt = 1e-1;
    for (int iphi = 0; iphi<nphi; iphi++) {
      for (int ieta = -neta; ieta<neta+1; ieta++) {
        double phi = (iphi+0.5) * (fj::twopi/nphi) + rand()*0.001/RAND_MAX;
        double eta = ieta * (10.0/neta)  + rand()*0.001/RAND_MAX;
        kt = 0.0000001*(1+rand()*0.1/RAND_MAX);
        double pminus = kt*exp(-eta);
        double pplus  = kt*exp(+eta);
        double px = kt*sin(phi);
        double py = kt*cos(phi);
        //cout << kt<<" "<<eta<<" "<<phi<<"\n";
        fj::PseudoJet mom(px,py,0.5*(pplus-pminus),0.5*(pplus+pminus));
        jets.push_back(mom);
      }
    }
  }
  
  fj::JetDefinition jet_def(jet_algorithm, ktR, strategy);

  for (int irepeat = 0; irepeat < repeat ; irepeat++) {
    fj::ClusterSequence clust_seq(jets,jet_def,write);
    if (irepeat != 0) {continue;}
    cout << "iev "<<iev<< ": number of particles = "<< jets.size() << endl;
    cout << "strategy used =  "<< clust_seq.strategy_string()<< endl;

    // now provide some nice output...
    if (inclkt >= 0.0) {
      vector<fj::PseudoJet> jets = sorted_by_pt(clust_seq.inclusive_jets(inclkt));
      for (size_t j = 0; j < jets.size(); j++) {
        printf("%5u %15.8f %15.8f %15.8f\n",j,jets[j].rap(),jets[j].phi(),sqrt(jets[j].kt2()));
        if (show_constituents) {
          vector<fj::PseudoJet> const_jets = clust_seq.constituents(jets[j]);
          for (size_t k = 0; k < const_jets.size(); k++) {
            printf("        jet%03u %15.8f %15.8f %15.8f\n",j,const_jets[k].rap(),
                   const_jets[k].phi(),sqrt(const_jets[k].kt2()));
          }
          cout << "\n\n";
        }
      }
    }

    if (excln > 0) {
      vector<fj::PseudoJet> jets = sorted_by_E(clust_seq.exclusive_jets(excln));
 
      cout << "Printing "<<excln<<" exclusive jets\n";
      for (size_t j = 0; j < jets.size(); j++) {
        printf("%5u %15.8f %15.8f %15.8f\n",
               //j,jets[j].rap(),jets[j].phi(),sqrt(jets[j].kt2()));
               j,jets[j].rap(),jets[j].phi(),jets[j].kt2());
      }
    }

    if (excld > 0.0) {
      vector<fj::PseudoJet> jets = sorted_by_pt(clust_seq.exclusive_jets(excld));
      cout << "Printing exclusive jets for d = "<<excld<<"\n";
      for (size_t j = 0; j < jets.size(); j++) {
        printf("%5u %15.8f %15.8f %15.8f\n",
               j,jets[j].rap(),jets[j].phi(),sqrt(jets[j].kt2()));
      }
    }
    
    // useful for testing that recombination sequences are unique
    if (unique_write) {
      vector<int> unique_history = clust_seq.unique_history_order();
      // construct the inverse of the above mapping
      vector<int> inv_unique_history(clust_seq.history().size());
      for (unsigned int i = 0; i < unique_history.size(); i++) {
        inv_unique_history[unique_history[i]] = i;}

      for (unsigned int i = 0; i < unique_history.size(); i++) {
        fj::ClusterSequence::history_element el = 
          clust_seq.history()[unique_history[i]];
        int uhp1 = el.parent1>=0 ? inv_unique_history[el.parent1] : el.parent1;
        int uhp2 = el.parent2>=0 ? inv_unique_history[el.parent2] : el.parent2;
        printf("%7d u %15.8e %7d u %7d u\n",i,el.dij,uhp1, uhp2);
      }
    }

  } // irepeat

  } // iev
}

double pow2

(

const double

x

)

[inline]

Definition at line 95 of file fastjet_timing.cc.

Referenced by main().

{return x*x;}

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