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#ifndef PerigeeConversions_H
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#define PerigeeConversions_H
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#include "DataFormats/Math/interface/AlgebraicROOTObjects.h"
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#include "TrackingTools/TrajectoryState/interface/FreeTrajectoryState.h"
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#include "TrackingTools/TrajectoryParametrization/interface/PerigeeTrajectoryParameters.h"
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#include "TrackingTools/TrajectoryParametrization/interface/PerigeeTrajectoryError.h"
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class TrajectoryStateClosestToPoint;
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/**
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* Class provides several methods to transform perigee parameters to and from
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* various other parametrisations.
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*/
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class PerigeeConversions
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{
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typedef FreeTrajectoryState FTS;
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public:
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/**
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* This method calculates the perigee parameters from a given FTS
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* and a reference point.
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*/
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PerigeeTrajectoryParameters ftsToPerigeeParameters(const FTS& originalFTS,
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const GlobalPoint& referencePoint, double& pt) const;
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PerigeeTrajectoryError ftsToPerigeeError(const FTS& originalFTS) const;
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// PerigeeTrajectoryParameters helixToPerigeeParameters
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// (const reco::helix::Parameters & helixPar, const GlobalPoint& referencePoint) const;
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//
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// PerigeeTrajectoryError helixToPerigeeError(const reco::helix::Parameters & helixPar,
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// const reco::helix::Covariance & helixCov) const;
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/**
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* This method returns the position (on the helix) at which the
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* parameters are defined
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*/
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GlobalPoint positionFromPerigee(const PerigeeTrajectoryParameters& parameters,
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const GlobalPoint& referencePoint) const;
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/**
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* This method returns the (Cartesian) momentum.
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* The parameters need not be the full perigee parameters, as long as the first
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* 3 parameters are the transverse curvature, theta and phi.
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*/
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GlobalVector momentumFromPerigee(const AlgebraicVector3& momentum,
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const TrackCharge& charge, const GlobalPoint& referencePoint,
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const MagneticField* field) const;
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/**
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* This method returns the (Cartesian) momentum from the PerigeeTrajectoryParameters
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*/
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GlobalVector momentumFromPerigee (const PerigeeTrajectoryParameters& parameters,
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double pt,
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const GlobalPoint& referencePoint) const;
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/**
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* This method returns the charge.
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*/
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TrackCharge chargeFromPerigee(const PerigeeTrajectoryParameters& perigee) const;
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CurvilinearTrajectoryError curvilinearError(const PerigeeTrajectoryError& perigeeError,
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const GlobalTrajectoryParameters& gtp) const;
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/**
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* Public constructor.
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* This constructor takes a momentum, with parameters
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* (transverse curvature, theta, phi) and a position, which is both the
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* reference position and the position at which the momentum is defined.
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* The covariance matrix is defined for these 6 parameters, in the order
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* (x, y, z, transverse curvature, theta, phi).
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*/
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TrajectoryStateClosestToPoint trajectoryStateClosestToPoint
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(const AlgebraicVector3& momentum, const GlobalPoint& referencePoint,
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const TrackCharge& charge, const AlgebraicSymMatrix66& theCovarianceMatrix,
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const MagneticField* field) const;
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/**
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* Jacobians of tranformations between the parametrixation
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* (x, y, z, transverse curvature, theta, phi) to Cartesian
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*/
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AlgebraicMatrix66 jacobianParameters2Cartesian
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(const AlgebraicVector3& momentum, const GlobalPoint& position,
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const TrackCharge& charge, const MagneticField* field) const;
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/**
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* Jacobians of tranformations between curvilinear frame at point of closest
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* approach in transverse plane and perigee frame. The fts must therefore be
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* given at exactly this point in order to yield the correct Jacobians.
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*/
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AlgebraicMatrix55 jacobianCurvilinear2Perigee(const FreeTrajectoryState& fts) const;
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AlgebraicMatrix55 jacobianPerigee2Curvilinear(const GlobalTrajectoryParameters& gtp) const;
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// AlgebraicMatrix jacobianHelix2Perigee(const reco::helix::Parameters & helixPar,
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// const reco::helix::Covariance & helixCov) const;
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};
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#endif
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