JetVariable.h

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//  -*- c++ -*- 
 
/*
  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef JETMONITORING_JETVARIABLE_H
#define JETMONITORING_JETVARIABLE_H
#include <vector>
 
#include "xAODJet/Jet.h"
 
 
 
 
namespace JetVar {
  template<typename T>
  using Accessor = SG::AuxElement::Accessor< T >;
 
 
  struct VectorValue {
    struct VectorWrapper {
      virtual ~VectorWrapper(){}
      virtual float at(int) const =0;
      virtual size_t size() const =0;
    };
    VectorValue(VectorWrapper * v=nullptr , float s=1.) : m_v(v), m_scale(s){}
    float operator[](int i) const {return m_v->at(i)*m_scale;}
    size_t size()const {return m_v->size();}
    std::unique_ptr<VectorWrapper> m_v;
    float m_scale=1;
  };
 
  
  class Variable {
  public:
    
    Variable(const std::string & name) : m_name(name) {}
    virtual ~Variable() = default;
    virtual float value(const xAOD::Jet &) const = 0;
 
    virtual bool isVector() const {return false;}
 
    virtual VectorValue vector(const xAOD::Jet &) const {return VectorValue();}
    
    
    virtual std::string name() const {return m_name;}
 
    float scale() const {return m_scale;}
    void setScale(float s)  { m_scale=s;}
 
 
 
    static std::unique_ptr<Variable> create(const std::string & name, const std::string &type="float", int index=-1);
 
    std::string m_name;
    float m_scale = 1;
    int m_index = -1;
  };
 
 
 
 
  // ********************************************************
  // Concrete implementations of Variable
 
 
  template<typename T>
  struct VariableAtt : public Variable {
    VariableAtt(const std::string & name) : Variable(name), m_acc(name) {}
    virtual float value(const xAOD::Jet & j) const { 
      if ( m_acc.isAvailable( j ) ) return m_acc(j)*m_scale;
      else return -999.;
    }
    Accessor<T> m_acc;    
  };
 
  
  
  template<typename T>
  struct VariableAtt<std::vector<T> > : public Variable {
    typedef typename std::vector<T> vect_t;
    struct VectorWrapperT : public VectorValue::VectorWrapper {
      VectorWrapperT(const vect_t *v): m_v(v){};
      float at(int i) const {return (*m_v)[i];}
      size_t size() const {return m_v->size();}
      const vect_t * m_v;
    };
    
    VariableAtt(const std::string & name, int index) : Variable(name), m_acc(name) {
      m_index=index;
    }
 
    virtual std::string name() const {
      if(isVector() )return m_name;
      return m_name+std::to_string(m_index);
    }
 
    // returns false if the index is valid : in this case it is a simple variable
    virtual bool isVector() const {return m_index==-1;}
 
    // use only if the index is valid
    virtual float value(const xAOD::Jet & j) const {
      if ( m_acc.isAvailable( j ) && m_index >= 0 && m_acc(j).size() > (unsigned) m_index ) {
        return m_acc(j)[m_index]*m_scale;
      }
      else return -999.;
    }
 
    virtual VectorValue vector(const xAOD::Jet &j) const {
      if ( m_acc.isAvailable( j ) ) {
        VectorValue v( new VectorWrapperT(&m_acc(j)) , m_scale ) ;
        return v;
      }
      else {
        VectorValue junk( new VectorWrapperT(&s_dummy), m_scale );
        return junk;
      }
    }
 
 
    Accessor<vect_t> m_acc;
    // this is the value used returned when a vector attribute is not accessible
    const static inline vect_t s_dummy{-999};
  };
 
  
  
 
  // *******************************************
  // The classes below represent variables not stored as attribute in the Jet EDM
  // 
  
  struct EVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return j.e()*m_scale;}    
  };
 
  struct PzVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return j.pz()*m_scale;}    
  };
 
  struct NconstitVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return j.numConstituents();}    
  };
 
  struct Rapidity : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return j.rapidity();}    
  };
  
  struct AbsEtaVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return fabs(j.eta());}    
  };
 
  struct EtVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { return j.p4().Et()*m_scale;}
  };
 
  struct FChargedVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const { 
      bool status = false;
      float constScalePt = 0.; 
      std::vector<float> SumPtChargedPFOPt500;
      status = j.getAttribute<float>("JetConstitScaleMomentum_pt", constScalePt ); // Jet pT at the constituent scale
      if (!status) return 0;
      status = j.getAttribute<std::vector<float> >("SumPtChargedPFOPt500", SumPtChargedPFOPt500 ); //Vector over all vertices in the event, each element contains the sum pT of all charged PFO with a pT > 0.5 GeV associated to the vertex.
      if (!status) return 0;
      return SumPtChargedPFOPt500.at(0)/=constScalePt; //definition of "fCharge", index 0 points to the primary vertex
    }
  };
  
  struct EM3FracVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const {
      float constitScaleEnergy = 0.;
      std::vector<float> samplingFrac;
      xAOD::JetFourMom_t fourVec;
      bool status = false;
 
      status = j.getAttribute<xAOD::JetFourMom_t>( "JetConstitScaleMomentum", fourVec ); // Jet four-momentum at constituent scale 
      if( status ) constitScaleEnergy = fourVec.E() * m_scale ;
      else return 0.;
      status = j.getAttribute<std::vector<float> >("EnergyPerSampling", samplingFrac ); //EnergyPerSampling is a vector of size 24; element i refers to the energy deposited in calo sampling i, see https://twiki.cern.ch/twiki/bin/viewauth/AtlasProtected/Run2JetMoments#Sampling_layers
      if( status ) return (samplingFrac[3]+samplingFrac[7])/constitScaleEnergy; //3 is 'EMB3' in the LAr barrel, 7 is 'EME3' in the LAr EM endcap
      else return 0.;
    } 
  };
 
  struct Tile0FracVar : public Variable {
    using Variable::Variable;
    virtual float value(const xAOD::Jet & j) const {
      float constitScaleEnergy = 0.;
      std::vector<float> samplingFrac;
      xAOD::JetFourMom_t fourVec;
      bool status = false;
 
      status = j.getAttribute<xAOD::JetFourMom_t>( "JetConstitScaleMomentum", fourVec ); // Jet four-momentum at constituent scale 
      if( status ) constitScaleEnergy = fourVec.E() * m_scale ;
      else return 0.;
      status = j.getAttribute<std::vector<float> >("EnergyPerSampling", samplingFrac ); // refer to EM3FracVar above
      if( status ) return (samplingFrac[12]+samplingFrac[18])/constitScaleEnergy; //12 is 'TileBar0' in the Tile barrel, 18 is 'TileExt0' in the Tile extended barrel
      else return 0.;
    } 
  };
 
}
 
#endif