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Mask/include/Vec4.h

69 lines
2.4 KiB
C++

/*
Class which represents a 4-momentum vector. Can perform vector addition, subtraction, dot product
and generate a boost vector to its rest frame as well as apply a boost to itself.
--GWM Dec 2020.
*/
#ifndef VEC4_H
#define VEC4_H
#include <cmath>
namespace Mask {
class Vec4 {
public:
Vec4();
Vec4(double px, double py, double pz, double E);
virtual ~Vec4();
void SetVectorCartesian(double px, double py, double pz, double E);
void SetVectorSpherical(double theta, double phi, double p, double E);
inline double GetE() const { return m_data[3]; }
inline double GetPx() const { return m_data[0]; }
inline double GetPy() const { return m_data[1]; }
inline double GetPz() const { return m_data[2]; }
inline double GetP() const { return std::sqrt(m_data[0]*m_data[0] + m_data[1]*m_data[1] + m_data[2]*m_data[2]); }
inline double GetPxy() const { return std::sqrt(m_data[0]*m_data[0] + m_data[1]*m_data[1]); }
inline double GetTheta() const { return GetPxy() == 0.0 && GetPz() == 0.0 ? 0.0 : Atan2(GetPxy(), GetPz()); }
inline double GetPhi() const {
double phi = Atan2(GetPy(), GetPx());
if(phi<0) phi += 2.0*M_PI;
return GetPx() == 0.0 && GetPy() == 0.0 ? 0.0 : phi;
}
inline double GetInvMass() const { return std::sqrt(GetE()*GetE() - GetP()*GetP()); }
inline double GetKE() const { return GetE() - GetInvMass(); }
inline const double* GetBoost() const { return &m_boost[0]; }
void ApplyBoost(const double* boost);
//Only intended for use in looping access!
inline const double operator[] (int index) const { return index>3 || index < 0 ? 0.0 : m_data[index]; }
inline Vec4& operator=(const Vec4& rhs) { SetVectorCartesian(rhs.GetPx(), rhs.GetPy(), rhs.GetPz(), rhs.GetE()); return *this; }
inline Vec4 operator+(const Vec4& rhs) const { return Vec4(rhs.GetPx()+GetPx(), rhs.GetPy()+GetPy(), rhs.GetPz()+GetPz(), rhs.GetE()+GetE()); }
inline Vec4 operator-(const Vec4& rhs) const { return Vec4(rhs.GetPx()-GetPx(), rhs.GetPy()-GetPy(), rhs.GetPz()-GetPz(), rhs.GetE()-GetE()); }
double Dot(const Vec4& rhs) const;
Vec4 Cross(const Vec4& rhs) const;
private:
void CalcBoostToCM();
//use instead of std::atan2. Better controll over x=0
inline double Atan2(double y, double x) const {
if(x != 0) return std::atan2(y, x);
else if( y > 0 ) return M_PI/2.0;
else if( y < 0 ) return -M_PI/2.0;
else return 0.0;
}
double m_data[4];
double m_boost[3];
};
}
#endif