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 23 of file CMSInsideOutAlgorithm.h.

Member Typedef Documentation

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

Definition at line 26 of file CMSInsideOutAlgorithm.h.

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

Definition at line 25 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 50 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 7 of file CMSInsideOutAlgorithm.cc.

References reco::deltaR2(), greaterByEtPseudoJet(), 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
  sort(fOutput.begin(), fOutput.end(), greaterByEtPseudoJet);
}

Member Data Documentation

double CMSInsideOutAlgorithm::growthParameterSquared_

private

Definition at line 61 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::maxSizeSquared_

private

Definition at line 62 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::minSizeSquared_

private

Definition at line 63 of file CMSInsideOutAlgorithm.h.

double CMSInsideOutAlgorithm::seedThresholdPt_

private

Definition at line 60 of file CMSInsideOutAlgorithm.h.