#include <JacobianCartesianToLocal.h>

Public Member Functions
const AlgebraicMatrix56 &	jacobian () const

	JacobianCartesianToLocal (const Surface &surface, const LocalTrajectoryParameters &localParameters)

Private Attributes
AlgebraicMatrix56	theJacobian

Detailed Description

Class which calculates the Jacobian matrix of the transformation from the Cartesian to the local frame. The Jacobian is calculated during construction and thereafter cached, enabling reuse of the same Jacobian without calculating it again.

Definition at line 15 of file JacobianCartesianToLocal.h.

Constructor & Destructor Documentation

◆ JacobianCartesianToLocal()

JacobianCartesianToLocal::JacobianCartesianToLocal	(	const Surface &	surface,
		const LocalTrajectoryParameters &	localParameters
	)

Constructor from local trajectory parameters and surface defining the local frame. NB!! No default constructor exists!

Definition at line 5 of file JacobianCartesianToLocal.cc.

     : theJacobian() {
   //LocalCoordinates 1 = (q/|p|, dx/dz, dy/dz, x, y)
   //LocalCoordinates 2 = (x, y, z, px, py, pz)
   //Transformation: q/|p| = q/sqrt(px*px + py*py + pz*pz)
   //                dx/dz = px/pz
   //                dy/dz = py/pz
   //                x     = x
   //                y     = y
   LocalVector plocal = localParameters.momentum();
   double px = plocal.x(), py = plocal.y(), pz = plocal.z();
   double p = plocal.mag();
   TrackCharge q = localParameters.charge();
   // for neutrals: qbp is 1/p instead of q/p -
   //   equivalent to charge 1
   if (q == 0)
     q = 1;
   //Jacobian theJacobian( (q/|p|, dx/dz, dy/dz, x, y) = f(x, y, z, px, py, pz) )
   theJacobian(0, 3) = -q * px / (p * p * p);
   theJacobian(0, 4) = -q * py / (p * p * p);
   theJacobian(0, 5) = -q * pz / (p * p * p);
   if (fabs(pz) > 0) {
     theJacobian(1, 3) = 1. / pz;
     theJacobian(1, 5) = -px / (pz * pz);
     theJacobian(2, 4) = 1. / pz;
     theJacobian(2, 5) = -py / (pz * pz);
   }
   theJacobian(3, 0) = 1.;
   theJacobian(4, 1) = 1.;
  
   /*
   LocalVector l1 = surface.toLocal(GlobalVector(1., 0., 0.));
   LocalVector l2 = surface.toLocal(GlobalVector(0., 1., 0.));
   LocalVector l3 = surface.toLocal(GlobalVector(0., 0., 1.));
   AlgebraicMatrix33 Rsub;
   Rsub(0,0) = l1.x(); Rsub(0,1) = l2.x(); Rsub(0,2) = l3.x();
   Rsub(1,0) = l1.y(); Rsub(1,1) = l2.y(); Rsub(1,2) = l3.y();
   Rsub(2,0) = l1.z(); Rsub(2,1) = l2.z(); Rsub(2,2) = l3.z();
   */
  
   AlgebraicMatrix33 Rsub;
   // need to be copied anhhow to go from float to double...
   Surface::RotationType const& rot = surface.rotation();
   Rsub(0, 0) = rot.xx();
   Rsub(0, 1) = rot.xy();
   Rsub(0, 2) = rot.xz();
   Rsub(1, 0) = rot.yx();
   Rsub(1, 1) = rot.yy();
   Rsub(1, 2) = rot.yz();
   Rsub(2, 0) = rot.zx();
   Rsub(2, 1) = rot.zy();
   Rsub(2, 2) = rot.zz();
  
   AlgebraicMatrix66 R;
   R.Place_at(Rsub, 0, 0);
   R.Place_at(Rsub, 3, 3);
   theJacobian = theJacobian * R;
   //dbg::dbg_trace(1,"Ca2L", localParameters.vector(),l1,l2,l3,theJacobian);
 }