// @(#)root/mathcore:$Name:  $:$Id: Cartesian3D.h,v 1.7 2007/06/14 15:40:52 moneta Exp $
// Authors: W. Brown, M. Fischler, L. Moneta    2005  

 /**********************************************************************
  *                                                                    *
  * Copyright (c) 2005 , LCG ROOT MathLib Team 			       *
  *                    & FNAL LCG ROOT Mathlib Team  		       *
  *                                                                    *
  *                                                                    *
  **********************************************************************/

// Header file for class Cartesian3D
// 
// Created by: Lorenzo Moneta  at Mon May 30 11:16:56 2005
// Major revamp:  M. FIschler  at Wed Jun  8 2005
// 
// Last update: $ID: $
// 
#ifndef ROOT_Math_GenVector_Cartesian3D 
#define ROOT_Math_GenVector_Cartesian3D  1

#ifndef ROOT_Math_GenVector_Polar3Dfwd 
#include "Math/GenVector/Polar3Dfwd.h"
#endif

#ifndef ROOT_Math_Math
#include "Math/Math.h"
#endif

#include <limits>


#ifndef ROOT_Math_GenVector_eta
#include "Math/GenVector/eta.h"
#endif


namespace ROOT { 

  namespace Math { 

  /** 
      Class describing a 3D cartesian coordinate system
      (x, y, z coordinates) 

      @ingroup GenVector
   */ 

template <class T = double> 
class Cartesian3D { 

public : 

   typedef T Scalar;

   /**
      Default constructor  with x=y=z=0 
   */
   Cartesian3D() : fX(0), fY(0), fZ(0) {  }

   /**
      Constructor from x,y,z coordinates
   */
   Cartesian3D(Scalar x, Scalar y, Scalar z) : fX(x), fY(y), fZ(z) {  } 

   /**
      Construct from any Vector or coordinate system implementing 
      X(), Y() and Z()
   */
   template <class CoordSystem> 
   explicit Cartesian3D(const CoordSystem & v) 
      : fX(v.X()), fY(v.Y()), fZ(v.Z()) {  }

   // for g++  3.2 and 3.4 on 32 bits found that the compiler generated copy ctor and assignment are much slower 
   // re-implement them ( there is no no need to have them with g++4)
   /**
      copy constructor
    */
   Cartesian3D(const Cartesian3D & v) :
      fX(v.X()), fY(v.Y()), fZ(v.Z()) {  }

   /**
      assignment operator 
    */
   Cartesian3D & operator= (const Cartesian3D & v) { 
      fX = v.x();  
      fY = v.y();  
      fZ = v.z();  
      return *this;
   }


   /**
      Set internal data based on an array of 3 Scalar numbers
   */ 
   void SetCoordinates( const Scalar src[] ) { fX=src[0]; fY=src[1]; fZ=src[2]; }

   /**
      get internal data into an array of 3 Scalar numbers
   */ 
   void GetCoordinates( Scalar dest[] ) const 
   { dest[0] = fX; dest[1] = fY; dest[2] = fZ; }

   /**
      Set internal data based on 3 Scalar numbers
   */ 
   void SetCoordinates(Scalar  x, Scalar  y, Scalar  z) { fX=x; fY=y; fZ=z; }

   /**
      get internal data into 3 Scalar numbers
   */ 
   void GetCoordinates(Scalar& x, Scalar& y, Scalar& z) const {x=fX; y=fY; z=fZ;}  				

   Scalar X()     const { return fX;}
   Scalar Y()     const { return fY;}
   Scalar Z()     const { return fZ;}
   Scalar Mag2()  const { return fX*fX + fY*fY + fZ*fZ;}
   Scalar Perp2() const { return fX*fX + fY*fY ;}
   Scalar Rho()   const { return std::sqrt( Perp2());}
   Scalar R()     const { return std::sqrt( Mag2());}
   Scalar Theta() const { return (fX==0 && fY==0 && fZ==0) ? 
                             0.0 : atan2(Rho(),Z());}
   Scalar Phi()   const { return (fX==0 && fY==0) ? 0.0 : atan2(fY,fX);}
 
   // pseudorapidity
   Scalar Eta() const { 
      return Impl::Eta_FromRhoZ ( Rho(),fZ);
   }

   /** 
       set the x coordinate value keeping y and z constant
   */ 
   void SetX(Scalar x) { fX = x; }

   /** 
       set the y coordinate value keeping x and z constant
   */ 
   void SetY(Scalar y) { fY = y; }

   /** 
       set the z coordinate value keeping x and y constant
   */ 
   void SetZ(Scalar z) { fZ = z; }

   /** 
       set all values using cartesian coordinates  
   */
   void SetXYZ(Scalar x, Scalar y, Scalar z) { 
      fX=x; 
      fY=y; 
      fZ=z; 
   }

   /**
      scale the vector by a scalar quantity a
   */
   void Scale(Scalar a) { fX *= a; fY *= a;  fZ *= a; }

   /**
      negate the vector
   */
   void Negate() { fX = -fX; fY = -fY;  fZ = -fZ; }

   /**
      Assignment from any class implementing x(),y() and z()
      (can assign from any coordinate system) 
   */
   template <class CoordSystem> 
   Cartesian3D & operator = (const CoordSystem & v) { 
      fX = v.x();  
      fY = v.y();  
      fZ = v.z();  
      return *this;
   }

   /**
      Exact equality
   */  
   bool operator == (const Cartesian3D & rhs) const {
      return fX == rhs.fX && fY == rhs.fY && fZ == rhs.fZ;
   }
   bool operator != (const Cartesian3D & 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
   T x() const { return X();}
   T y() const { return Y();}
   T z() const { return Z(); } 
  
   // ============= Overloads for improved speed ==================

   template <class T2>
   explicit Cartesian3D( const Polar3D<T2> & v ) : fZ (v.Z())
   {
      T rho = v.Rho(); // re-using this instead of calling v.X() and v.Y()
      // is the speed improvement
      fX = rho * std::cos(v.Phi());
      fY = rho * std::sin(v.Phi());    
   } 
   // Technical note:  This works even though only Polar3Dfwd.h is 
   // included (and in fact, including Polar3D.h would cause circularity
   // problems). It works because any program **using** this ctor must itself
   // be including Polar3D.h.
    
   template <class T2>
   Cartesian3D & operator = (const Polar3D<T2> & v) 
   { 
      T rho = v.Rho(); 
      fX = rho * std::cos(v.Phi());
      fY = rho * std::sin(v.Phi());
      fZ = v.Z();
      return *this;
   }



#if defined(__MAKECINT__) || defined(G__DICTIONARY) 

   // ====== Set member functions for coordinates in other systems =======

   void SetR(Scalar r);
  
   void SetTheta(Scalar theta);  
  
   void SetPhi(Scalar phi); 
  
   void SetRho(Scalar rho); 
  
   void SetEta(Scalar eta);

#endif


private:

   /**
      (Contiguous) data containing the coordinates values x,y,z
   */
   T fX;
   T fY;
   T fZ; 
};


  } // end namespace Math

} // end namespace ROOT


#if defined(__MAKECINT__) || defined(G__DICTIONARY) 
// 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 "Math/GenVector/GenVector_exception.h"
#include "Math/GenVector/CylindricalEta3D.h"
#include "Math/GenVector/Polar3D.h"

  // ====== Set member functions for coordinates in other systems =======

namespace ROOT { 

  namespace Math { 

template <class T>  
void Cartesian3D<T>::SetR(Scalar r) {  
   GenVector_exception e("Cartesian3D::SetR() is not supposed to be called");
   Throw(e);
   Polar3D<Scalar> v(*this); v.SetR(r); *this = Cartesian3D<Scalar>(v);
}

template <class T>  
void Cartesian3D<T>::SetTheta(Scalar theta) {  
   GenVector_exception e("Cartesian3D::SetTheta() is not supposed to be called");
   Throw(e);
   Polar3D<Scalar> v(*this); v.SetTheta(theta); *this = Cartesian3D<Scalar>(v);
}

template <class T>  
void Cartesian3D<T>::SetPhi(Scalar phi) {  
   GenVector_exception e("Cartesian3D::SetPhi() is not supposed to be called");
   Throw(e);
   Polar3D<Scalar> v(*this); v.SetPhi(phi); *this = Cartesian3D<Scalar>(v);
}

template <class T>  
void Cartesian3D<T>::SetRho(Scalar rho) {  
   GenVector_exception e("Cartesian3D::SetRho() is not supposed to be called");
   Throw(e);
   CylindricalEta3D<Scalar> v(*this); v.SetRho(rho); 
   *this = Cartesian3D<Scalar>(v);
}

template <class T>  
void Cartesian3D<T>::SetEta(Scalar eta) {  
   GenVector_exception e("Cartesian3D::SetEta() is not supposed to be called");
   Throw(e);
   CylindricalEta3D<Scalar> v(*this); v.SetEta(eta); 
    *this = Cartesian3D<Scalar>(v);
}



  } // end namespace Math

} // end namespace ROOT

#endif




#endif /* ROOT_Math_GenVector_Cartesian3D  */