#include <JacobianCurvilinearToLocal.h>

Public Member Functions
const AlgebraicMatrix55 &	jacobian () const

	JacobianCurvilinearToLocal (const Surface &surface, const LocalTrajectoryParameters &localParameters, const GlobalTrajectoryParameters &globalParameters, const MagneticField &magField)

	JacobianCurvilinearToLocal (const Surface &surface, const LocalTrajectoryParameters &localParameters, const MagneticField &magField)

Private Member Functions
void	compute (Surface::RotationType const &rot, GlobalVector const &tn, GlobalVector const &qh, double lz)

Private Attributes
AlgebraicMatrix55	theJacobian

Detailed Description

Class which calculates the Jacobian matrix of the transformation from the curvilinear 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 19 of file JacobianCurvilinearToLocal.h.

Constructor & Destructor Documentation

◆ JacobianCurvilinearToLocal() [1/2]

JacobianCurvilinearToLocal::JacobianCurvilinearToLocal	(	const Surface &	surface,
		const LocalTrajectoryParameters &	localParameters,
		const MagneticField &	magField
	)

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

Definition at line 8 of file JacobianCurvilinearToLocal.cc.

     : theJacobian(ROOT::Math::SMatrixNoInit()) {
   GlobalPoint x = surface.toGlobal(localParameters.position());
   GlobalVector h = magField.inInverseGeV(x);
   GlobalVector qh = h * localParameters.signedInverseMomentum();  // changed sign
  
   LocalVector tnl = localParameters.direction();
   GlobalVector tn = surface.toGlobal(tnl);
   double t1r = 1. / tnl.z();
  
   Surface::RotationType const& rot = surface.rotation();
  
   compute(rot, tn, qh, t1r);
 }

References compute(), LocalTrajectoryParameters::direction(), MagneticField::inInverseGeV(), LocalTrajectoryParameters::position(), makeMuonMisalignmentScenario::rot, GloballyPositioned< T >::rotation(), LocalTrajectoryParameters::signedInverseMomentum(), Surface::toGlobal(), x, and PV3DBase< T, PVType, FrameType >::z().

◆ JacobianCurvilinearToLocal() [2/2]

JacobianCurvilinearToLocal::JacobianCurvilinearToLocal	(	const Surface &	surface,
		const LocalTrajectoryParameters &	localParameters,
		const GlobalTrajectoryParameters &	globalParameters,
		const MagneticField &	magField
	)

Definition at line 25 of file JacobianCurvilinearToLocal.cc.

     : theJacobian(ROOT::Math::SMatrixNoInit()) {
   // GlobalPoint  x =  globalParameters.position();
   // GlobalVector h  = magField.inInverseGeV(x);
   GlobalVector h = globalParameters.magneticFieldInInverseGeV();
   GlobalVector qh = h * localParameters.signedInverseMomentum();  // changed sign
  
   LocalVector tnl = localParameters.direction();
   // GlobalVector tn = surface.toGlobal(tnl); // faster?
   GlobalVector tn = globalParameters.momentum() * std::abs(localParameters.signedInverseMomentum());
   double t1r = 1. / tnl.z();
  
   Surface::RotationType const& rot = surface.rotation();
  
   compute(rot, tn, qh, t1r);
 }

References funct::abs(), compute(), LocalTrajectoryParameters::direction(), GlobalTrajectoryParameters::magneticFieldInInverseGeV(), GlobalTrajectoryParameters::momentum(), makeMuonMisalignmentScenario::rot, GloballyPositioned< T >::rotation(), LocalTrajectoryParameters::signedInverseMomentum(), and PV3DBase< T, PVType, FrameType >::z().

Member Function Documentation

◆ compute()

void JacobianCurvilinearToLocal::compute	(	Surface::RotationType const &	rot,
		GlobalVector const &	tn,
		GlobalVector const &	qh,
		double	lz
	)

private

Definition at line 45 of file JacobianCurvilinearToLocal.cc.

                                                      {
   // Origin: TRSCSD
  
   double cosl = tn.perp();
   if (cosl < 1.e-30)
     cosl = 1.e-30;
   double cosl1 = 1. / cosl;
   GlobalVector un(-tn.y() * cosl1, tn.x() * cosl1, 0.);
   GlobalVector vn(-tn.z() * un.y(), tn.z() * un.x(), cosl);
  
   auto u = rot.rotate(un.basicVector());
   auto v = rot.rotate(vn.basicVector());
  
   int j = 0, k = 1, i = 2;
  
   double t2r = t1r * t1r;
   double t3r = t1r * t2r;
  
   theJacobian(0, 0) = 1.;
   for (auto i = 1; i < 5; ++i)
     theJacobian(0, i) = 0.;
   theJacobian(1, 0) = 0.;
   theJacobian(2, 0) = 0.;
  
   theJacobian(1, 1) = -u[k] * t2r;
   theJacobian(1, 2) = v[k] * (cosl * t2r);
   theJacobian(2, 1) = u[j] * t2r;
   theJacobian(2, 2) = -v[j] * (cosl * t2r);
  
   for (auto i = 0; i < 3; ++i) {
     theJacobian(3, i) = 0.;
     theJacobian(4, i) = 0.;
   }
  
   theJacobian(3, 3) = v[k] * t1r;
   theJacobian(3, 4) = -u[k] * t1r;
   theJacobian(4, 3) = -v[j] * t1r;
   theJacobian(4, 4) = u[j] * t1r;
  
   double sinz = un.dot(qh);
   double cosz = -vn.dot(qh);
   double ui = u[i] * (t3r);
   double vi = v[i] * (t3r);
   theJacobian(1, 3) = -ui * (v[k] * cosz - u[k] * sinz);
   theJacobian(1, 4) = -vi * (v[k] * cosz - u[k] * sinz);
   theJacobian(2, 3) = ui * (v[j] * cosz - u[j] * sinz);
   theJacobian(2, 4) = vi * (v[j] * cosz - u[j] * sinz);
   // end of TRSCSD
   //dbg::dbg_trace(1,"Cu2L", localParameters.vector(),di,dj,dk,theJacobian);
 }