/data/refman/pasoursint/CMSSW_6_1_2_SLHC2/src/DataFormats/GeometryVector/interface/VectorUtil.h

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#ifndef GeometryVector_Geom_Util_h
#define GeometryVector_Geom_Util_h



#include "DataFormats/GeometryVector/interface/Pi.h"
#include "Math/VectorUtil.h" 
#include <cmath>


namespace Geom {

  inline double deltaBarePhi(double phi1, double phi2) { 
    double dphi = phi2-phi1; 
    if ( dphi > M_PI ) {
      dphi -= 2.0*M_PI;
    } else if ( dphi <= -M_PI ) {
      dphi += 2.0*M_PI;
    }
    return dphi;
  }
  inline double deltaPhi(float phi1, float phi2) { 
    using ROOT::Math::VectorUtil::Phi_mpi_pi;
    return deltaBarePhi(Phi_mpi_pi(phi2),Phi_mpi_pi(phi1));
  }
  inline double deltaPhi(double phi1, double phi2) { 
    using ROOT::Math::VectorUtil::Phi_mpi_pi;
    return deltaBarePhi(Phi_mpi_pi(phi2),Phi_mpi_pi(phi1));
  }
  template <class Vector1, class Vector2> 
  double deltaPhi( const Vector1 & v1, const Vector2 & v2) { 
    return deltaBarePhi(v1.phi(),v2.phi()); 
  }
  

  /*
  inline bool phiLess( float phi1, float phi2) {
    float diff = fmod(phi2 - phi1, 2.0*M_PI);
    // float diff = phi2-phi1; 
    if ( diff < 0) diff += 2*M_PI;
    return diff < M_PI;
  }
  */
  inline bool phiLess(float phi1, float phi2) {
    return deltaPhi(phi1,phi2)<0;
  }
  inline bool phiLess(double phi1, double phi2) {
    return deltaPhi(phi1,phi2)<0;
  }
  template <class Vector1, class Vector2> 
  bool phiLess(const Vector1 & v1, const Vector2 & v2) {
    return deltaPhi(v1,v2)<0.; 
  }

    
  template <class Vector1, class Vector2> 
  double deltaR2( const Vector1 & v1, const Vector2 & v2) { 
    double dphi = deltaPhi(v1,v2); 
    double deta = v2.eta() - v1.eta(); 
    return dphi*dphi + deta*deta; 
  }
  template <class Vector1, class Vector2> 
  double deltaR( const Vector1 & v1, const Vector2 & v2) { 
    return std::sqrt( deltaR2(v1,v2));
  }
  
}

#endif