EigenP5toP4JacobianPhiThetaEM2PxPyPzE.cxx

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/*
  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
*/
 
#include "FourMom/EigenP5toP4JacobianPhiThetaEM2PxPyPzE.h"
#include <cmath>
 
EigenP5toP4JacobianPhiThetaEM2PxPyPzE::EigenP5toP4JacobianPhiThetaEM2PxPyPzE(const double phi0, 
                                         const double theta, 
                                         const double E, 
                                         const double mass ):
  AmgMatrix(4,5)()
{
  this->setZero();
  double sinp = std::sin(phi0);
  double cosp = std::cos(phi0);
  double sint = std::sin(theta);
  double cost = std::cos(theta);
  double mom  = std::sqrt((E*E)-(mass*mass));
 
  // transformation of track parameters
  double px = mom*cosp*sint;
  double py = mom*sinp*sint;
  double pz = mom*cost;
  double EoverP = E/mom;
  
 
  (*this)(0,2) = -py; // dpx/dphi0
  (*this)(0,3) =  pz*cosp; // dpx/dtheta
  (*this)(0,4) =  EoverP*sint*cosp; // dpx/E
  
  (*this)(1,2) =  px; // dpy/dphi0
  (*this)(1,3) =  pz*sinp; // dpy/dtheta
  (*this)(1,4) =  EoverP*sint*sinp; // dpy/dE
  
  (*this)(2,3) = -sint*mom; // dpz/dtheta
  (*this)(2,4) =  EoverP*cost; // dpz/dE
 
  (*this)(3,4) =  1.; // dE/dE
  
}