BoostX.h

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// @(#)root/mathcore:$Id$
// Authors: W. Brown, M. Fischler, L. Moneta    2005
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2005 ROOT FNAL MathLib Team                          *
 *                                                                    *
 *                                                                    *
 **********************************************************************/
 
// Header file for BoostX
//
// Created by: Mark Fischler  Mon Nov 1  2005
//
// Last update: $Id$
//
#ifndef ROOT_MathX_GenVectorX_BoostX
#define ROOT_MathX_GenVectorX_BoostX 1
 
#include "MathX/GenVectorX/LorentzVector.h"
#include "MathX/GenVectorX/PxPyPzE4D.h"
#include "MathX/GenVectorX/DisplacementVector3D.h"
#include "MathX/GenVectorX/Cartesian3D.h"
 
#include "MathX/GenVectorX/AccHeaders.h"
 
using namespace ROOT::ROOT_MATH_ARCH;
 
namespace ROOT {
 
namespace ROOT_MATH_ARCH {
 
//__________________________________________________________________________________________
/**
   Class representing a Lorentz Boost along the X axis, by beta.
   For efficiency, gamma is held as well.
 
   @ingroup GenVectorX
 
   @see GenVectorX
*/
 
class BoostX {
 
public:
   typedef double Scalar;
 
   enum ELorentzRotationMatrixIndex {
      kLXX = 0,
      kLXY = 1,
      kLXZ = 2,
      kLXT = 3,
      kLYX = 4,
      kLYY = 5,
      kLYZ = 6,
      kLYT = 7,
      kLZX = 8,
      kLZY = 9,
      kLZZ = 10,
      kLZT = 11,
      kLTX = 12,
      kLTY = 13,
      kLTZ = 14,
      kLTT = 15
   };
 
   enum EBoostMatrixIndex {
      kXX = 0,
      kXY = 1,
      kXZ = 2,
      kXT = 3,
      kYY = 4,
      kYZ = 5,
      kYT = 6,
      kZZ = 7,
      kZT = 8,
      kTT = 9
   };
 
   // ========== Constructors and Assignment =====================
 
   /**
       Default constructor (identity transformation)
   */
   BoostX();
 
   /**
      Construct given a Scalar beta_x
   */
   explicit BoostX(Scalar beta_x) { SetComponents(beta_x); }
 
   // The compiler-generated copy ctor, copy assignment, and dtor are OK.
 
   /**
      Re-adjust components to eliminate small deviations from a perfect
      orthosyplectic matrix.
   */
   void Rectify();
 
   // ======== Components ==============
 
   /**
      Set components from a Scalar beta_x
   */
   void SetComponents(Scalar beta_x);
 
   /**
      Get components into a Scalar beta_x
   */
   void GetComponents(Scalar &beta_x) const;
 
   /**
       Retrieve the beta of the Boost
   */
   Scalar Beta() const { return fBeta; }
 
   /**
       Retrieve the gamma of the Boost
   */
   Scalar Gamma() const { return fGamma; }
 
   /**
       Set the given beta of the Boost
   */
   void SetBeta(Scalar beta) { SetComponents(beta); }
 
   /**
      The beta vector for this boost
   */
   typedef DisplacementVector3D<Cartesian3D<double>, DefaultCoordinateSystemTag> XYZVector;
   XYZVector BetaVector() const;
 
   /**
      Get elements of internal 4x4 symmetric representation, into a data
      array suitable for direct use as the components of a LorentzRotation
      Note -- 16 Scalars will be written into the array; if the array is not
      that large, then this will lead to undefined behavior.
   */
   void GetLorentzRotation(Scalar r[]) const;
 
   // =========== operations ==============
 
   /**
      Lorentz transformation operation on a Minkowski ('Cartesian')
      LorentzVector
   */
   LorentzVector<PxPyPzE4D<double>> operator()(const LorentzVector<PxPyPzE4D<double>> &v) const;
 
   /**
      Lorentz transformation operation on a LorentzVector in any
      coordinate system
   */
   template <class CoordSystem>
   LorentzVector<CoordSystem> operator()(const LorentzVector<CoordSystem> &v) const
   {
      LorentzVector<PxPyPzE4D<double>> xyzt(v);
      LorentzVector<PxPyPzE4D<double>> r_xyzt = operator()(xyzt);
      return LorentzVector<CoordSystem>(r_xyzt);
   }
 
   /**
      Lorentz transformation operation on an arbitrary 4-vector v.
      Preconditions:  v must implement methods x(), y(), z(), and t()
      and the arbitrary vector type must have a constructor taking (x,y,z,t)
   */
   template <class Foreign4Vector>
   Foreign4Vector operator()(const Foreign4Vector &v) const
   {
      LorentzVector<PxPyPzE4D<double>> xyzt(v);
      LorentzVector<PxPyPzE4D<double>> r_xyzt = operator()(xyzt);
      return Foreign4Vector(r_xyzt.X(), r_xyzt.Y(), r_xyzt.Z(), r_xyzt.T());
   }
 
   /**
      Overload operator * for operation on a vector
   */
   template <class A4Vector>
   inline A4Vector operator*(const A4Vector &v) const
   {
      return operator()(v);
   }
 
   /**
      Invert a BoostX in place
   */
   void Invert();
 
   /**
      Return inverse of  a boost
   */
   BoostX Inverse() const;
 
   /**
      Equality/inequality operators
   */
   bool operator==(const BoostX &rhs) const
   {
      if (fBeta != rhs.fBeta)
         return false;
      if (fGamma != rhs.fGamma)
         return false;
      return true;
   }
 
   bool operator!=(const BoostX &rhs) const { return !operator==(rhs); }
 
private:
   Scalar fBeta;  // boost beta X
   Scalar fGamma; // boost gamma
 
}; // BoostX
 
// ============ Class BoostX ends here ============
 
/**
   Stream Output and Input
*/
// TODO - I/O should be put in the manipulator form
#if !defined(ROOT_MATH_SYCL) && !defined(ROOT_MATH_CUDA)
 
std::ostream &operator<<(std::ostream &os, const BoostX &b);
 
#endif
 
} // namespace ROOT_MATH_ARCH
} // namespace ROOT
 
#endif /* ROOT_MathX_GenVectorX_BoostX  */