KinematicHelper.cxx

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//=============================================
// Kinematic Helper class
//=============================================
//
// Implementation
//
#include "AtlfastUtils/KinematicHelper.h"

#include "AtlfastEvent/IKinematic.h"
#include "AtlfastEvent/Phi.h"

namespace Atlfast {

//------------------------------------------
// Return the distance in eta-phi space between two objects
  //template< class Item1, class Item2 >
  //double KinematicHelper::deltaR( Item1* aa , Item2* bb )
double KinematicHelper::deltaR( IKinematic* a , IKinematic* b )
{ 
  //IKinematic* a = this->regulateType( aa ) ;
  //IKinematic* b = this->regulateType( bb ) ;

  // Doing this takes care of cyclic algebra
  Phi aphi(a->phi()) ;
  Phi bphi(b->phi()) ; 

  double dist = 
    sqrt(
         (aphi - bphi)*(aphi - bphi) +
         (a->eta() - b->eta())*(a->eta() - b->eta()) 
         );
  return dist ;
}

double KinematicHelper::deltaR( IKinematic& a , IKinematic& b )
{ 
  return this->deltaR( &a, &b ) ;
}

//------------------------------------------
// Return the distance in phi space between two objects
double KinematicHelper::deltaPhi( IKinematic* a , IKinematic* b )
{ 
  return std::abs( Phi( a->phi() - b->phi() ) ) ;
}

double KinematicHelper::deltaPhi( IKinematic& a , IKinematic& b )
{ 
  return this->deltaPhi( &a, &b ) ;
}

//------------------------------------------
// Return the invariant mass of two objects
double KinematicHelper::mass( IKinematic* a , IKinematic* b )
{ 
  return ( a->momentum() + b->momentum() ).m() ;
}

double KinematicHelper::mass( IKinematic& a , IKinematic& b )
{ 
  return this->mass( &a, &b ) ;
}


} // namespace end

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