Cartesian2D.h

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// @(#)root/mathcore:$Id: b12794c790afad19142e34a401af6c233aba446b $
// Authors: W. Brown, M. Fischler, L. Moneta    2005
 
/**********************************************************************
 *                                                                    *
 * Copyright (c) 2005 , LCG ROOT MathLib Team                         *
 *                    & FNAL LCG ROOT Mathlib Team                    *
 *                                                                    *
 *                                                                    *
 **********************************************************************/
 
// Header file for class Cartesian2D
//
// Created by: Lorenzo Moneta  at Mon 16 Apr 2007
//
#ifndef ROOT_MathX_GenVectorX_Cartesian2D
#define ROOT_MathX_GenVectorX_Cartesian2D 1
 
#include "MathX/GenVectorX/Polar2Dfwd.h"
 
#include "Math/Math.h"
 
#include "MathX/GenVectorX/MathHeaders.h"
 
#include "MathX/GenVectorX/AccHeaders.h"
 
using namespace ROOT::ROOT_MATH_ARCH;
 
namespace ROOT {
 
namespace ROOT_MATH_ARCH {
 
//__________________________________________________________________________________________
/**
    Class describing a 2D cartesian coordinate system
    (x, y coordinates)
 
    @ingroup GenVectorX
 
    @see GenVectorX
*/
 
template <class T = double>
class Cartesian2D {
 
public:
   typedef T Scalar;
 
   /**
      Default constructor  with x=y=0
   */
   constexpr Cartesian2D() noexcept = default;
 
   /**
      Constructor from x,y  coordinates
   */
   Cartesian2D(Scalar xx, Scalar yy) : fX(xx), fY(yy) {}
 
   /**
      Construct from any Vector or coordinate system implementing
      X() and Y()
   */
   template <class CoordSystem>
   explicit constexpr Cartesian2D(const CoordSystem &v) : fX(v.X()), fY(v.Y())
   {
   }
 
   /**
      Set internal data based on 2 Scalar numbers
   */
   void SetCoordinates(Scalar xx, Scalar yy)
   {
      fX = xx;
      fY = yy;
   }
 
   /**
      get internal data into 2 Scalar numbers
   */
   void GetCoordinates(Scalar &xx, Scalar &yy) const
   {
      xx = fX;
      yy = fY;
   }
 
   Scalar X() const { return fX; }
   Scalar Y() const { return fY; }
   Scalar Mag2() const { return fX * fX + fY * fY; }
   Scalar R() const { return math_sqrt(Mag2()); }
   Scalar Phi() const { return (fX == Scalar(0) && fY == Scalar(0)) ? Scalar(0) : math_atan2(fY, fX); }
 
   /**
       set the x coordinate value keeping y constant
   */
   void SetX(Scalar a) { fX = a; }
 
   /**
       set the y coordinate value keeping x constant
   */
   void SetY(Scalar a) { fY = a; }
 
   /**
       set all values using cartesian coordinates
   */
   void SetXY(Scalar xx, Scalar yy)
   {
      fX = xx;
      fY = yy;
   }
 
   /**
      scale the vector by a scalar quantity a
   */
   void Scale(Scalar a)
   {
      fX *= a;
      fY *= a;
   }
 
   /**
      negate the vector
   */
   void Negate()
   {
      fX = -fX;
      fY = -fY;
   }
 
   /**
       rotate by an angle
    */
   void Rotate(Scalar angle)
   {
      const Scalar s = math_sin(angle);
      const Scalar c = math_cos(angle);
      SetCoordinates(c * fX - s * fY, s * fX + c * fY);
   }
 
   /**
      Assignment from any class implementing x(),y()
      (can assign from any coordinate system)
   */
   template <class CoordSystem>
   Cartesian2D &operator=(const CoordSystem &v)
   {
      fX = v.x();
      fY = v.y();
      return *this;
   }
 
   /**
      Exact equality
   */
   bool operator==(const Cartesian2D &rhs) const { return fX == rhs.fX && fY == rhs.fY; }
   bool operator!=(const Cartesian2D &rhs) const { return !(operator==(rhs)); }
 
   // ============= Compatibility section ==================
 
   // The following make this coordinate system look enough like a CLHEP
   // vector that an assignment member template can work with either
   Scalar x() const { return X(); }
   Scalar y() const { return Y(); }
 
   // ============= Overloads for improved speed ==================
 
   template <class T2>
   explicit Cartesian2D(const Polar2D<T2> &v)
   {
      const Scalar r = v.R(); // re-using this instead of calling v.X() and v.Y()
      // is the speed improvement
      fX = r * math_cos(v.Phi());
      fY = r * math_sin(v.Phi());
   }
   // Technical note:  This works even though only Polar2Dfwd.h is
   // included (and in fact, including Polar2D.h would cause circularity
   // problems). It works because any program **using** this ctor must itself
   // be including Polar2D.h.
 
   template <class T2>
   Cartesian2D &operator=(const Polar2D<T2> &v)
   {
      const Scalar r = v.R();
      fX = r * math_cos(v.Phi());
      fY = r * math_sin(v.Phi());
      return *this;
   }
 
#if defined(__ROOTCLING__) || defined(G__DICTIONARY)
 
   // ====== Set member functions for coordinates in other systems =======
 
   void SetR(Scalar r);
 
   void SetPhi(Scalar phi);
 
#endif
 
private:
   /**
      (Contiguous) data containing the coordinates values x and y
   */
   T fX = 0;
   T fY = 0;
};
 
} // end namespace ROOT_MATH_ARCH
 
} // end namespace ROOT
 
#if defined(__ROOTCLING__) || defined(G__DICTIONARY)
#if !defined(ROOT_MATH_SYCL) && !defined(ROOT_MATH_CUDA)
// need to put here setter methods to resolve nasty cyclical dependencies
// I need to include other coordinate systems only when Cartesian is already defined
// since they depend on it
 
#include "MathX/GenVectorX/GenVector_exception.h"
#include "MathX/GenVectorX/Polar2D.h"
 
// ====== Set member functions for coordinates in other systems =======
 
namespace ROOT {
 
namespace ROOT_MATH_ARCH {
 
template <class T>
void Cartesian2D<T>::SetR(Scalar r)
{
   GenVector_exception e("Cartesian2D::SetR() is not supposed to be called");
   throw e;
   Polar2D<Scalar> v(*this);
   v.SetR(r);
   *this = Cartesian2D<Scalar>(v);
}
 
template <class T>
void Cartesian2D<T>::SetPhi(Scalar phi)
{
   GenVector_exception e("Cartesian2D::SetPhi() is not supposed to be called");
   throw e;
   Polar2D<Scalar> v(*this);
   v.SetPhi(phi);
   *this = Cartesian2D<Scalar>(v);
}
 
} // namespace ROOT_MATH_ARCH
 
} // end namespace ROOT
 
#endif
#endif
 
#endif /* ROOT_MathX_GenVectorX_Cartesian2D  */