CMSInsideOutAlgorithm Class Reference

#include <CMSInsideOutAlgorithm.h>

Classes
class	ListIteratorLesserByDeltaR

Public Types
typedef std::list < fastjet::PseudoJet > ::iterator	inputListIter
typedef reco::Particle::LorentzVector	LorentzVector

Public Member Functions
	CMSInsideOutAlgorithm (double seedObjectPt, double growthParameter, double maxSize, double minSize)
void	run (const std::vector< fastjet::PseudoJet > &fInput, std::vector< fastjet::PseudoJet > &fOutput)
	Build from input candidate collection. More...

Private Attributes
double	growthParameterSquared_
double	maxSizeSquared_
double	minSizeSquared_
double	seedThresholdPt_

Detailed Description

Definition at line 27 of file CMSInsideOutAlgorithm.h.

Member Typedef Documentation

typedef std::list<fastjet::PseudoJet>::iterator CMSInsideOutAlgorithm::inputListIter

Definition at line 30 of file CMSInsideOutAlgorithm.h.

typedef reco::Particle::LorentzVector CMSInsideOutAlgorithm::LorentzVector

Definition at line 29 of file CMSInsideOutAlgorithm.h.

Constructor & Destructor Documentation

CMSInsideOutAlgorithm::CMSInsideOutAlgorithm ( double  seedObjectPt, double  growthParameter, double  maxSize, double  minSize  )

inline

Constructor

Parameters

seed	defines the minimum ET in GeV of an object that can seed the jet
growthparameter	sets the growth parameter X, i.e. [dR < X/Et_jet]
min/max	size define the min/max size of jet in deltaR. Min is included for resolution effects
seedCharge	can be the following values; -1 [don't care], 0 neutral only, 1 [tracks only]

Definition at line 52 of file CMSInsideOutAlgorithm.h.

                                                                                                        : 
         seedThresholdPt_(seedObjectPt),
         growthParameterSquared_(growthParameter*growthParameter),
         maxSizeSquared_(maxSize*maxSize),
         minSizeSquared_(minSize*minSize){};

Member Function Documentation

void CMSInsideOutAlgorithm::run	(	const std::vector< fastjet::PseudoJet > &	fInput,
		std::vector< fastjet::PseudoJet > &	fOutput
	)

Build from input candidate collection.

Definition at line 9 of file CMSInsideOutAlgorithm.cc.

References reco::deltaR2(), input, and position.

Referenced by CMSInsideOutJetProducer::runAlgorithm().

{

   //make a list of input objects
   list<fastjet::PseudoJet> input;
   for (std::vector<fastjet::PseudoJet>::const_iterator candIter  = fInput.begin();
    candIter != fInput.end(); 
    ++candIter) {
      input.push_back(*candIter);
   }

   while( !input.empty() && input.front().perp() > seedThresholdPt_ ) 
   {
      //get seed eta/phi
      double seedEta = input.front().eta();
      double seedPhi = input.front().phi();

      //find iterators to those objects that are in the max cone size
      list<inputListIter> maxCone;
      // add seed, then test elements after seed
      inputListIter iCand = input.begin();
      maxCone.push_back(iCand++);
      for(; iCand != input.end(); ++iCand)
      {
    const fastjet::PseudoJet& candidate = *iCand;
         if( reco::deltaR2(seedEta, candidate.eta(), seedPhi, candidate.phi()) < maxSizeSquared_ )
            maxCone.push_back(iCand);
      }
      //sort objects by increasing DR about the seed  directions
      maxCone.sort(ListIteratorLesserByDeltaR(seedEta, seedPhi));
      list<inputListIter>::const_iterator position = maxCone.begin(); 
      bool limitReached = false;
      double totalET    = (**position).perp();
      ++position;
      while(position != maxCone.end() && !limitReached)
      {
     const fastjet::PseudoJet& theCandidate = **position;
         double candidateET    = theCandidate.perp() + totalET; 
         double candDR2        = reco::deltaR2(seedEta, theCandidate.eta(), seedPhi, theCandidate.phi());
         if( candDR2 < minSizeSquared_ ||  candDR2*candidateET*candidateET < growthParameterSquared_ )
            totalET = candidateET;
         else
            limitReached = true;
         ++position;
      }
      //turn this into a final jet
      fastjet::PseudoJet final;
      for(list<inputListIter>::const_iterator iNewJet  = maxCone.begin();
                                              iNewJet != position;
                                            ++iNewJet)
      {
     final += **iNewJet;
         input.erase(*iNewJet);
      }
      fOutput.push_back(final);
   } // end loop over seeds
   GreaterByEtPseudoJet compJets;
   sort (fOutput.begin (), fOutput.end (), compJets);
}

Member Data Documentation

double CMSInsideOutAlgorithm::growthParameterSquared_

private

Definition at line 65 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::maxSizeSquared_

private

Definition at line 66 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::minSizeSquared_

private

Definition at line 67 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::seedThresholdPt_

private

Definition at line 64 of file CMSInsideOutAlgorithm.h.