StJetFinder/StKtCluJetFinder.cxx

// -*- mode: c++;-*-
#include "StKtCluJetFinder.h"

//std
#include <cmath>
#include <float.h>

//root
#include "TObject.h"

//JetFinder
#include "FourVec.h"
#include "StProtoJet.h"
#include "StProtoJetPair.h"
#include "StJetFinder.h"


using namespace std;

    
StKtCluJetFinder::StKtCluJetFinder(const StKtCluPars& pars) : mPars(pars)
{
    cout <<"StKtCluJetFinder::StKtCluJetFinder()"<<endl;
}

StKtCluJetFinder::~StKtCluJetFinder()
{
    cout <<"StKtCluJetFinder::~StKtCluJetFinder()"<<endl;
}

void StKtCluJetFinder::Init()
{

}

void StKtCluJetFinder::findJets(JetList& pj, const FourVecList& particleList)
{
  pj.clear();
  
  for(FourVecList::const_iterator particle = particleList.begin(); particle != particleList.end(); ++particle) {
    pj.push_back(StProtoJet(*particle));
  }

    if (pj.size()<2) return; //nothing to be done!
    
    mJets.clear();
    int nSteps = 0;
        
    while (pj.empty()==false) {
                
        if ( mPars.debug() ) {
            cout <<"\n --- protojets after clustering "<<nSteps<<" steps"<<endl;
            for (JetList::const_iterator it3=pj.begin(); it3!=pj.end(); ++it3) {
                cout <<*it3<<endl;
            }
            cout <<"   --- jets after clustering "<<nSteps<<" steps"<<endl;
            for (JetList::const_iterator it4=mJets.begin(); it4!=mJets.end(); ++it4) {
                cout <<*it4<<endl;
            }
                        
        }

        //Find the smallest d in protojets:
        double d_min_pj = DBL_MAX;
        JetList::iterator bestProto=pj.end();
                
        //Loop on protojets first:
        for (JetList::iterator protoIt=pj.begin(); protoIt!=pj.end(); ++protoIt) {
            double d = (*protoIt).d();
            if (d<d_min_pj) {
                bestProto = protoIt;
                d_min_pj = d;
            }
        }
                
        //Find the smallest d in protojet pairs:
        double d_min_jets = DBL_MAX;
        JetList::iterator bestJet1=pj.end();
        JetList::iterator bestJet2=pj.end();
                
        for (JetList::iterator jetIt1=pj.begin(); jetIt1!=pj.end(); ++jetIt1) {
            for (JetList::iterator jetIt2=jetIt1; jetIt2!=pj.end(); ++jetIt2) {
                if (jetIt1!=jetIt2) {
                    StProtoJetPair myPair(*jetIt1, *jetIt2, mPars.r());
                    double d = myPair.d();
                    if (d < d_min_jets) {
                        d_min_jets=d;
                        bestJet1 = jetIt1;
                        bestJet2 = jetIt2;
                    }
                }
            }
        }
                
        //Now we choose what to do:
                
        if (d_min_pj < d_min_jets) {
                        
            //this proto-jet is unmergable, move it into jet list
                        
            if (bestProto==pj.end()) {
                cout <<"StJetFinder::findJets(). ERROR:\t"
                     <<"Trying to use protojet iterator that doesn't exist"<<endl;
            }
            (*bestProto).update();
            mJets.push_back(*bestProto);
            pj.erase(bestProto);
        }
                
        //else if (d_min_pj > d_min_jets) {
        else {
            //these two protojets should be merged
                        
            if (bestJet1==pj.end() || bestJet2==pj.end()) {
                cout <<"StJetFinder::findJets(). ERROR:\t"
                     <<"Trying to use 2 protojet iterators, one doesn't exist"<<endl;
            }
            (*bestJet1).merge(*bestJet2);
            pj.erase(bestJet2);
        }
        /*
          else {
          cout <<"JetFinder::findJets().  ERROR:\t"
          <<"No choice made"<<endl;
          }
        */
        ++nSteps;
    }
        
    //Now we're all done, copy the jets into the original container, return
    for (JetList::iterator it=mJets.begin(); it!=mJets.end(); ++it) {
        pj.push_back(*it);
    }
        
}

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