JetSubStructureUtils::SphericityTensor Class Reference

#include <SphericityTensor.h>

Inheritance diagram for JetSubStructureUtils::SphericityTensor:

Collaboration diagram for JetSubStructureUtils::SphericityTensor:

Public Member Functions
virtual std::map< std::string, double >	result (const fastjet::PseudoJet &jet) const
virtual TOut	result (const xAOD::Jet &jet) const

Detailed Description

Definition at line 11 of file SphericityTensor.h.

Member Function Documentation

result() [1/2]

map< string, double > SphericityTensor::result ( const fastjet::PseudoJet & jet ) const

virtual

Definition at line 15 of file SphericityTensor.cxx.

{
  map<string, double> Variables;
  Variables["Sphericity"] = -999.*1000.;
  Variables["Aplanarity"] = -999.*1000.;
 
  vector<fastjet::PseudoJet> clusters = boostToCenterOfMass(jet, jet.constituents());
  if(clusters.size() < 2) return Variables;
 
  TMatrixD MomentumTensor(3,3);
  double P2Sum = 0;
 
  for(std::vector<fastjet::PseudoJet>::const_iterator Itr=clusters.begin(); Itr!=clusters.end(); ++Itr) {
    MomentumTensor(0,0) += (*Itr).px()*(*Itr).px();
    MomentumTensor(0,1) += (*Itr).px()*(*Itr).py();
    MomentumTensor(0,2) += (*Itr).px()*(*Itr).pz();
    MomentumTensor(1,0) += (*Itr).py()*(*Itr).px();
    MomentumTensor(1,1) += (*Itr).py()*(*Itr).py();
    MomentumTensor(1,2) += (*Itr).py()*(*Itr).pz();
    MomentumTensor(2,0) += (*Itr).pz()*(*Itr).px();
    MomentumTensor(2,1) += (*Itr).pz()*(*Itr).py();
    MomentumTensor(2,2) += (*Itr).pz()*(*Itr).pz();
 
    P2Sum += (*Itr).px()*(*Itr).px()+(*Itr).py()*(*Itr).py()+(*Itr).pz()*(*Itr).pz();
  }
 
  double Aplanarity = -1;
  double Sphericity = -1;
 
  if(P2Sum > 0) {
    const double inv_P2Sum = 1. / P2Sum;
    for(int i=0; i<3; i++) {
      for(int j=0; j<3; j++) {
        MomentumTensor(i,j) *= inv_P2Sum;
      }
    }
 
    TDecompSVD * aSVD = new TDecompSVD(MomentumTensor);
    TVectorD Lambda = aSVD->GetSig();
 
    Aplanarity = 1.5*Lambda[2];
    Sphericity = 1.5*(Lambda[1]+Lambda[2]);
 
    delete aSVD;
  }
  else {
    return Variables;
  }
 
  Variables["Aplanarity"] = Aplanarity;
  Variables["Sphericity"] = Sphericity;
  return Variables;  
}

result() [2/2]

virtual TOut JetSubStructureUtils::SubstructureCalculator< TOut >::result ( const xAOD::Jet & jet ) const

inlinevirtual

Reimplemented from JetSubStructureUtils::SubstructureCalculator< std::map< std::string, double > >.

Definition at line 25 of file SubstructureCalculator.h.

                                                    {
        // PS 4/18 master developent
        // std::vector<fastjet::PseudoJet> constit_pseudojets =
        //   jet::JetConstituentFiller::constituentPseudoJets(jet);
 
        std::vector<fastjet::PseudoJet> constit_pseudojets;
        std::transform(jet.getConstituents().begin(),
                       jet.getConstituents().end(),
                       std::back_inserter(constit_pseudojets),
                       [](const auto& c){
                         const xAOD::IParticle* ip = c->rawConstituent();
                         return
                           // fastjet::PseudoJet((c->rawConstituent())->p4());
                           fastjet::PseudoJet(ip->p4());
                       });
 
        fastjet::PseudoJet pjet = fastjet::join(constit_pseudojets);
 
        return result(pjet);
      }

---

The documentation for this class was generated from the following files:

• SphericityTensor.h
• SphericityTensor.cxx