RotationL.cc

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// -*- C++ -*-
// ---------------------------------------------------------------------------
//
// This file is a part of the CLHEP - a Class Library for High Energy Physics.
//
// This is the implementation of methods of the HepRotation class which
// were introduced when ZOOM PhysicsVectors was merged in, which might cause 
// pulling in of LorentzTransformation related code units.
//
 
#include "CLHEP/Vector/defs.h"
#include "CLHEP/Vector/Rotation.h"
#include "CLHEP/Vector/LorentzRotation.h"
 
#include <cmath>
 
namespace CLHEP  {
 
// ----------  distance2 and related member functions:
//
// WHy do we have forms for HepLorentzRotation and HepBoost but not for 
// HepBoostX, HepBoostY, HepBoostZ?  Because the latter can be gotten by 
// implicit conversion to HepBoost; but if we just had HepLorentzRotation 
// then this would involve double conversion when HepBoostX was used.
 
double HepRotation::distance2( const HepLorentzRotation & lt  ) const {
  HepAxisAngle a; 
  Hep3Vector   b;
  lt.decompose(b, a);
  double bet = b.beta();
  double bet2 = bet*bet;
  HepRotation r(a);
  return bet2/(1-bet2) + distance2(r);
}
 
double HepRotation::distance2( const HepBoost & lt ) const {
  return distance2( HepLorentzRotation(lt));
}
 
double HepRotation::howNear( const HepLorentzRotation & lt  ) const {
  return  std::sqrt( distance2( lt ) );
}
 
double HepRotation::howNear( const HepBoost & lt  ) const {
  return  std::sqrt( distance2( lt ) );
}
 
bool HepRotation::isNear(   const HepLorentzRotation & lt,
                                     double epsilon) const {
 return  distance2( lt ) <= epsilon*epsilon;
}
 
bool HepRotation::isNear(   const HepBoost & lt,
                                     double epsilon) const {
 return  distance2( lt ) <= epsilon*epsilon;
}
 
}  // namespace CLHEP