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//----------------------------------------------------------------------
// This file distributed with FastJet has been obtained from SpartyJet
// v2.20.0 by Pierre-Antoine Delsart, Kurtis L. Geerlings, Joey
// Huston, Brian T. Martin and Chris Vermilion
// For details, see http://www.pa.msu.edu/~huston/SpartyJet/
// http://projects.hepforge.org/spartyjet/
//
// Changes from the original file are listed below.
//----------------------------------------------------------------------
// History of changes compared to the original LorentzVector.hh file
//
// 2011-11-14 Gregory Soyez <soyez@fastjet.fr>
//
// * removed some harmless warnings coming with the -Wshadow gcc option
//
// 2009-01-15 Gregory Soyez <soyez@fastjet.fr>
//
// * put the code in the fastjet::atlas namespace
#ifndef _LORENTZ_VECTOR_HH_
#define _LORENTZ_VECTOR_HH_
#include <cmath>
#include "fastjet/internal/base.hh"
#ifndef M_PI
#define M_PI 3.141592653589793238462643383279502884197
#endif
FASTJET_BEGIN_NAMESPACE
namespace atlas{
class LorentzVector
{
public:
double px,py,pz,E;
LorentzVector(): px(0), py(0), pz(0), E(0) {}
LorentzVector(double p1, double p2, double p3, double p0): px(p1), py(p2), pz(p3), E(p0) {}
LorentzVector(const LorentzVector& lv): px(lv.px), py(lv.py), pz(lv.pz), E(lv.E) {}
double p() const {return sqrt(px*px + py*py + pz*pz);}
double pt() const {return sqrt(px*px + py*py);}
double mt() const {return sqrt((E-pz)*(E+pz));}
double y() const {return 0.5*log((E + pz)/(E - pz));}
double Et() const {return E/p()*pt();}
inline double et() const {return Et();}
inline double e() const {return E;}
double eta() const {return 0.5*log((p() + pz)/(p() - pz));}
double phi() const
{
double r = atan2(py,px);
if(r < 0)
r += 2*M_PI;
return r;
}
void add(LorentzVector v)
{
px += v.px;
py += v.py;
pz += v.pz;
E += v.E;
}
void subtract(LorentzVector v)
{
px -= v.px;
py -= v.py;
pz -= v.pz;
E -= v.E;
}
bool isEqual(LorentzVector v)
{
return px == v.px && py == v.py && pz == v.pz && E == v.E;
}
};
} // namespace atlas
FASTJET_END_NAMESPACE
#endif
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