// -*- C++ -*-
// $Id:$
// ---------------------------------------------------------------------------
//
// This file is a part of the CLHEP - a Class Library for High Energy Physics.
// 
// This is the definitions of the inline member functions of the
// Hep3Vector class.
//

#include <cmath>

namespace CLHEP {

// ------------------
// Access to elements
// ------------------

// x, y, z

inline double & Hep3Vector::operator[] (int i)       { return operator()(i); }
inline double   Hep3Vector::operator[] (int i) const { return operator()(i); }

inline double Hep3Vector::x() const { return dx; }
inline double Hep3Vector::y() const { return dy; }
inline double Hep3Vector::z() const { return dz; }

inline double Hep3Vector::getX() const { return dx; }
inline double Hep3Vector::getY() const { return dy; }
inline double Hep3Vector::getZ() const { return dz; }

inline void Hep3Vector::setX(double x1) { dx = x1; }
inline void Hep3Vector::setY(double y1) { dy = y1; }
inline void Hep3Vector::setZ(double z1) { dz = z1; }

inline void Hep3Vector::set(double x1, double y1, double z1) { 
  dx = x1; 
  dy = y1; 
  dz = z1; 
}

inline double Hep3Vector::operator () (int i) const {
  switch(i) {
  case X:
    return x();
  case Y:
    return y();
  case Z:
    return z();
  }
  return 0.;
}

inline double & Hep3Vector::operator () (int i) {
  static double dummy;
  switch(i) {
  case X:
    return dx;
  case Y:
    return dy;
  case Z:
    return dz;
  }
  return dummy;
}

// --------------
// Global methods
// --------------

inline Hep3Vector operator + (const Hep3Vector & a, const Hep3Vector & b) {
  return Hep3Vector(a.x() + b.x(), a.y() + b.y(), a.z() + b.z());
}

inline Hep3Vector operator - (const Hep3Vector & a, const Hep3Vector & b) {
  return Hep3Vector(a.x() - b.x(), a.y() - b.y(), a.z() - b.z());
}

inline Hep3Vector operator * (const Hep3Vector & p, double a) {
  return Hep3Vector(a*p.x(), a*p.y(), a*p.z());
}

inline Hep3Vector operator * (double a, const Hep3Vector & p) {
  return Hep3Vector(a*p.x(), a*p.y(), a*p.z());
}

inline double operator * (const Hep3Vector & a, const Hep3Vector & b) {
  return a.dot(b);
}

// --------------------------
// Set in various coordinates
// --------------------------

inline void Hep3Vector::setRThetaPhi
		  ( double r1, double theta1, double phi1 ) {
  setSpherical (r1, theta1, phi1); 
}

inline void Hep3Vector::setREtaPhi
		  ( double r1, double eta1,  double phi1 ) {
  setSpherical (r1, 2*std::atan(std::exp(-eta1)), phi1); 
}

inline void Hep3Vector::setRhoPhiZ
		  ( double rho1, double phi1, double z1) {
  setCylindrical (rho1, phi1, z1); 
}

// ------------
// Constructors
// ------------

inline Hep3Vector::Hep3Vector()
  : dx(0.), dy(0.), dz(0.) {}
inline Hep3Vector::Hep3Vector(double x1)
  : dx(x1), dy(0.), dz(0.) {}
inline Hep3Vector::Hep3Vector(double x1, double y1)
  : dx(x1), dy(y1), dz(0.) {}
inline Hep3Vector::Hep3Vector(double x1, double y1, double z1)
  : dx(x1), dy(y1), dz(z1) {}

inline Hep3Vector::Hep3Vector(const Hep3Vector & p)
: dx(p.dx), dy(p.dy), dz(p.dz) {}

inline Hep3Vector::~Hep3Vector() {}

inline Hep3Vector & Hep3Vector::operator = (const Hep3Vector & p) {
  dx = p.dx;
  dy = p.dy;
  dz = p.dz;
  return *this;
}

// ------------------
// Access to elements
// ------------------

// r, theta, phi

inline double Hep3Vector::mag2() const { return dx*dx + dy*dy + dz*dz; }
inline double Hep3Vector::mag()  const { return std::sqrt(mag2()); }
inline double Hep3Vector::r()    const { return mag(); }

inline double Hep3Vector::theta() 	const {
  return dx == 0.0 && dy == 0.0 && dz == 0.0 ? 0.0 : std::atan2(perp(),dz);
}
inline double Hep3Vector::phi() const {
  return dx == 0.0 && dy == 0.0 ? 0.0 : std::atan2(dy,dx);
}

inline double Hep3Vector::getR()     const { return mag();   }
inline double Hep3Vector::getTheta() const { return theta(); }
inline double Hep3Vector::getPhi()   const { return phi();   }
inline double Hep3Vector::angle()    const { return theta(); }

inline double Hep3Vector::cosTheta() const {
  double ptot = mag();
  return ptot == 0.0 ? 1.0 : dz/ptot;
}

inline double Hep3Vector::cos2Theta() const {
  double ptot2 = mag2();
  return ptot2 == 0.0 ? 1.0 : dz*dz/ptot2;
}

inline void Hep3Vector::setR(double r1) { setMag(r1); }

inline void Hep3Vector::setTheta(double th) {
  double ma   = mag();
  double ph   = phi();
  setX(ma*std::sin(th)*std::cos(ph));
  setY(ma*std::sin(th)*std::sin(ph));
  setZ(ma*std::cos(th));
}

inline void Hep3Vector::setPhi(double ph) {
  double xy   = perp();
  setX(xy*std::cos(ph));
  setY(xy*std::sin(ph));
}

// perp, eta, 

inline double Hep3Vector::perp2()  const { return dx*dx + dy*dy; }
inline double Hep3Vector::perp()   const { return std::sqrt(perp2()); }
inline double Hep3Vector::rho()    const { return perp();  }
inline double Hep3Vector::eta()    const { return pseudoRapidity();}

inline double Hep3Vector::getRho() const { return perp();  }
inline double Hep3Vector::getEta() const { return pseudoRapidity();}

inline void Hep3Vector::setPerp(double r1) {
  double p = perp();
  if (p != 0.0) {
    dx *= r1/p;
    dy *= r1/p;
  }
}
inline void Hep3Vector::setRho(double rho1) { setPerp (rho1); }

// ----------
// Comparison
// ----------

inline bool Hep3Vector::operator == (const Hep3Vector& v) const {
  return (v.x()==x() && v.y()==y() && v.z()==z()) ? true : false;
}

inline bool Hep3Vector::operator != (const Hep3Vector& v) const {
  return (v.x()!=x() || v.y()!=y() || v.z()!=z()) ? true : false;
}

inline double Hep3Vector::getTolerance () {
  return tolerance;
}

// ----------
// Arithmetic
// ----------

inline Hep3Vector& Hep3Vector::operator += (const Hep3Vector & p) {
  dx += p.x();
  dy += p.y();
  dz += p.z();
  return *this;
}

inline Hep3Vector& Hep3Vector::operator -= (const Hep3Vector & p) {
  dx -= p.x();
  dy -= p.y();
  dz -= p.z();
  return *this;
}

inline Hep3Vector Hep3Vector::operator - () const {
  return Hep3Vector(-dx, -dy, -dz);
}

inline Hep3Vector& Hep3Vector::operator *= (double a) {
  dx *= a;
  dy *= a;
  dz *= a;
  return *this;
}

// -------------------
// Combine two Vectors
// -------------------

inline double Hep3Vector::diff2(const Hep3Vector & p) const {
  return (*this-p).mag2();
}

inline double Hep3Vector::dot(const Hep3Vector & p) const {
  return dx*p.x() + dy*p.y() + dz*p.z();
}

inline Hep3Vector Hep3Vector::cross(const Hep3Vector & p) const {
  return Hep3Vector(dy*p.z()-p.y()*dz, dz*p.x()-p.z()*dx, dx*p.y()-p.x()*dy);
}

inline double Hep3Vector::perp2(const Hep3Vector & p)  const {
  double tot = p.mag2();
  double ss  = dot(p);
  return tot > 0.0 ? mag2()-ss*ss/tot : mag2();
}

inline double Hep3Vector::perp(const Hep3Vector & p) const {
  return std::sqrt(perp2(p));
}

inline Hep3Vector Hep3Vector::perpPart () const {
  return Hep3Vector (dx, dy, 0);
}
inline Hep3Vector Hep3Vector::project () const {
  return Hep3Vector (0, 0, dz);
}

inline Hep3Vector Hep3Vector::perpPart (const Hep3Vector & v2) const {
  return ( *this - project(v2) );
}

inline double Hep3Vector::angle(const Hep3Vector & q) const {
  return std::acos(cosTheta(q));
}

inline double Hep3Vector::theta(const Hep3Vector & q) const { 
  return angle(q); 
}

inline double Hep3Vector::azimAngle(const Hep3Vector & v2) const { 
  return deltaPhi(v2); 
}

// ----------
// Properties
// ----------

inline Hep3Vector Hep3Vector::unit() const {
  double  tot = mag2();
  Hep3Vector p(x(),y(),z());
  return tot > 0.0 ? p *= (1.0/std::sqrt(tot)) : p;
}

inline Hep3Vector Hep3Vector::orthogonal() const {
  double xx = dx < 0.0 ? -dx : dx;
  double yy = dy < 0.0 ? -dy : dy;
  double zz = dz < 0.0 ? -dz : dz;
  if (xx < yy) {
    return xx < zz ? Hep3Vector(0,dz,-dy) : Hep3Vector(dy,-dx,0);
  }else{
    return yy < zz ? Hep3Vector(-dz,0,dx) : Hep3Vector(dy,-dx,0);
  }
}

}  // namespace CLHEP