FastJet 3.0.2
LorentzVector.hh
00001 //----------------------------------------------------------------------
00002 // This file distributed with FastJet has been obtained from SpartyJet
00003 // v2.20.0 by Pierre-Antoine Delsart, Kurtis L. Geerlings, Joey
00004 // Huston, Brian T. Martin and Chris Vermilion
00005 // For details, see http://www.pa.msu.edu/~huston/SpartyJet/
00006 //                  http://projects.hepforge.org/spartyjet/
00007 //
00008 // Changes from the original file are listed below.
00009 //----------------------------------------------------------------------
00010 
00011 // History of changes compared to the original LorentzVector.hh file
00012 // 
00013 // 2011-11-14  Gregory Soyez  <soyez@fastjet.fr>
00014 //
00015 //        * removed some harmless warnings coming with the -Wshadow gcc option
00016 // 
00017 // 2009-01-15  Gregory Soyez  <soyez@fastjet.fr>
00018 //
00019 //        * put the code in the fastjet::atlas namespace
00020 
00021 #ifndef _LORENTZ_VECTOR_HH_
00022 #define _LORENTZ_VECTOR_HH_
00023 
00024 #include <cmath>
00025 #include <fastjet/internal/base.hh>
00026 
00027 #ifndef M_PI
00028 #define M_PI  3.141592653589793238462643383279502884197 
00029 #endif
00030 
00031 FASTJET_BEGIN_NAMESPACE
00032 
00033 namespace atlas{
00034 
00035 class LorentzVector
00036 {
00037  public:
00038 
00039   double px,py,pz,E;
00040 
00041   LorentzVector(): px(0), py(0), pz(0), E(0) {}
00042   LorentzVector(double p1, double p2, double p3, double p0): px(p1), py(p2), pz(p3), E(p0) {}
00043   LorentzVector(const LorentzVector& lv): px(lv.px), py(lv.py), pz(lv.pz), E(lv.E) {}
00044   double p()   const {return sqrt(px*px + py*py + pz*pz);}
00045   double pt()  const {return sqrt(px*px + py*py);}
00046   double mt()  const {return sqrt((E-pz)*(E+pz));}
00047   double y()   const {return 0.5*log((E + pz)/(E - pz));}
00048   double Et()  const {return E/p()*pt();}
00049   inline double et()  const {return Et();}
00050   inline double e()  const {return E;}
00051   double eta() const {return 0.5*log((p() + pz)/(p() - pz));}
00052   double phi() const
00053   {
00054     double r = atan2(py,px);
00055     if(r < 0)
00056       r += 2*M_PI;
00057     return r;
00058   }
00059   void add(LorentzVector v)
00060   {
00061     px += v.px;
00062     py += v.py;
00063     pz += v.pz;
00064     E  += v.E;
00065   }
00066   void subtract(LorentzVector v)
00067   {
00068     px -= v.px;
00069     py -= v.py;
00070     pz -= v.pz;
00071     E  -= v.E;
00072   }
00073   bool isEqual(LorentzVector v)
00074   {
00075     return px == v.px && py == v.py && pz == v.pz && E == v.E;
00076   }
00077 };
00078 
00079 } // namespace atlas
00080 
00081 FASTJET_END_NAMESPACE
00082 
00083 #endif
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