source: trunk/KtJet/KtRecom.cc

#include "KtJet/KtRecom.h"
#include "KtJet/KtUtil.h"
#include "KtJet/KtRecomInterface.h"
#include <string>

namespace KtJet {
  //using CLHEP::HepLorentzVector;
  using namespace CLHEP;

  KtRecom* getRecomScheme(int recom) {
    if (recom == 1)   return new KtRecomE();
    else if (recom == 2)   return new KtRecomPt();
    else if (recom == 3)   return new KtRecomPt2();
    else if (recom == 4)   return new KtRecomEt();
    else if (recom == 5)   return new KtRecomEt2();
    else{
      std::cout << "WARNING, unreconised recombination scheme specified!" << std::endl;
      std::cout << "Recombination Scheme set to KtRecomE" << std::endl;
      return new KtRecomE();
    }
  }


  KtRecomE::KtRecomE() : m_name("E") {}
  //KtRecomE::~KtRecomE() {}
  std::string KtRecomE::name() const {return m_name;}

  HepLorentzVector KtRecomE::operator()(const HepLorentzVector &a, const HepLorentzVector &b) const {
    return a+b;
  }

  KtLorentzVector KtRecomE::operator()(const KtLorentzVector &a) const {
    return a;
  }

  KtRecomPt::KtRecomPt() : m_name("Pt") {}
  //KtRecomPt::~KtRecomPt() {}
  std::string KtRecomPt::name() const {return m_name;}

  HepLorentzVector KtRecomPt::operator()(const HepLorentzVector &a, const HepLorentzVector &b) const {
    KtFloat pti, ptj, newPt, newEta, newPhi, deltaPhi;
    pti = a.perp();
    ptj = b.perp();
    newPt = pti + ptj;
    newEta = (pti * a.eta() + ptj * b.eta()) / newPt;
    deltaPhi = phiAngle(b.phi() - a.phi());
    newPhi = a.phi() + deltaPhi * ptj / newPt;
    newPhi = phiAngle(newPhi);
    return HepLorentzVector(newPt*cos(newPhi),newPt*sin(newPhi),newPt*sinh(newEta),newPt*cosh(newEta));
  }

  /** Make 4-vector massless by setting E = p */
  KtLorentzVector KtRecomPt::operator()(const KtLorentzVector &a) const {
    KtLorentzVector v = a;
    v.setE(a.vect().mag());
    return v;
  }


  KtRecomPt2::KtRecomPt2() : m_name("Pt^2") {}
  //KtRecomPt2::~KtRecomPt2() {}
  std::string KtRecomPt2::name() const {return m_name;}

  HepLorentzVector KtRecomPt2::operator()(const HepLorentzVector &a, const HepLorentzVector &b) const {
    KtFloat pti, ptj, ptisq, ptjsq, newPt, newEta, newPhi, deltaPhi;
    pti = a.perp();
    ptj = b.perp();
    ptisq = a.perp2();
    ptjsq = b.perp2();
    newPt = pti + ptj;
    newEta = (ptisq * a.eta() + ptjsq * b.eta()) / (ptisq + ptjsq);
    deltaPhi = phiAngle(b.phi() - a.phi());
    newPhi = a.phi() + deltaPhi * ptjsq / (ptisq + ptjsq);
    newPhi = phiAngle(newPhi);
    return HepLorentzVector(newPt*cos(newPhi),newPt*sin(newPhi),newPt*sinh(newEta),newPt*cosh(newEta));
  }

  /** Make 4-vector massless by setting E = p */
  KtLorentzVector KtRecomPt2::operator()(const KtLorentzVector &a) const {
    KtLorentzVector v = a;
    v.setE(a.vect().mag());
    return v;
  }


  KtRecomEt::KtRecomEt() : m_name("Et") {}
  //KtRecomEt::~KtRecomEt() {}
  std::string KtRecomEt::name() const {return m_name;}

  HepLorentzVector KtRecomEt::operator()(const HepLorentzVector &a, const HepLorentzVector &b) const {
    KtFloat pti, ptj, newPt, newEta, newPhi, deltaPhi;
    pti = a.et();
    ptj = b.et();
    newPt = pti + ptj;
    newEta = (pti * a.eta() + ptj * b.eta()) / newPt;
    deltaPhi = phiAngle(b.phi() - a.phi());
    newPhi = a.phi() + deltaPhi * ptj / newPt;
    newPhi = phiAngle(newPhi);
    return HepLorentzVector(newPt*cos(newPhi),newPt*sin(newPhi),newPt*sinh(newEta),newPt*cosh(newEta));
  }

  /** Make 4-vector massless by scaling momentum to equal E */
  KtLorentzVector KtRecomEt::operator()(const KtLorentzVector &a) const {
    KtLorentzVector v = a;
    KtFloat scale = a.e() / a.vect().mag();
    v.setVect(a.vect() * scale);
    return v;
  }


  KtRecomEt2::KtRecomEt2() : m_name("Et^2") {}
  //KtRecomEt2::~KtRecomEt2() {}
  std::string KtRecomEt2::name() const {return m_name;}

  HepLorentzVector KtRecomEt2::operator()(const HepLorentzVector &a, const HepLorentzVector &b) const {
    KtFloat pti, ptj, ptisq, ptjsq, newPt, newEta, newPhi, deltaPhi;
    pti = a.et();
    ptj = b.et();
    ptisq = pti*pti;
    ptjsq = ptj*ptj;
    newPt = pti + ptj;
    newEta = (ptisq * a.eta() + ptjsq * b.eta()) / (ptisq + ptjsq);
    deltaPhi = phiAngle(b.phi() - a.phi());
    newPhi = a.phi() + deltaPhi * ptjsq / (ptisq + ptjsq);
    newPhi = phiAngle(newPhi);
    return HepLorentzVector(newPt*cos(newPhi),newPt*sin(newPhi),newPt*sinh(newEta),newPt*cosh(newEta));
  }

  /** Make 4-vector massless by scaling momentum to equal E */
  KtLorentzVector KtRecomEt2::operator()(const KtLorentzVector &a) const {
    KtLorentzVector v = a;
    KtFloat scale = a.e() / a.vect().mag();
    v.setVect(a.vect() * scale);
    return v;
  }

}//end of namespace