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#include "TrackingTools/PatternTools/interface/TransverseImpactPointExtrapolator.h"
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#include "TrackingTools/TrajectoryState/interface/TrajectoryStateOnSurface.h"
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#include "DataFormats/GeometrySurface/interface/Surface.h"
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#include "boost/intrusive_ptr.hpp"
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#include "TrackingTools/TrajectoryState/interface/FreeTrajectoryState.h"
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#include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
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#include "TrackingTools/GeomPropagators/interface/AnalyticalPropagator.h"
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#include "DataFormats/GeometryVector/interface/Point2DBase.h"
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#include "DataFormats/GeometryVector/interface/Vector2DBase.h"
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#include "DataFormats/GeometrySurface/interface/PlaneBuilder.h"
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#include "FWCore/MessageLogger/interface/MessageLogger.h"
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TransverseImpactPointExtrapolator::TransverseImpactPointExtrapolator () :
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thePropagator(0) {}
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TransverseImpactPointExtrapolator::TransverseImpactPointExtrapolator (const MagneticField* field) :
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thePropagator(new AnalyticalPropagator(field, anyDirection)) {}
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TransverseImpactPointExtrapolator::TransverseImpactPointExtrapolator (const Propagator& u) :
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thePropagator(u.clone())
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{
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thePropagator->setPropagationDirection(anyDirection);
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::extrapolate (const FreeTrajectoryState& fts,
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const GlobalPoint& vtx) const
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{
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return doExtrapolation(fts, vtx, *thePropagator);
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::extrapolate (const TrajectoryStateOnSurface tsos,
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const GlobalPoint& vtx) const
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{
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if ( !tsos.isValid() ) return tsos;
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return doExtrapolation(tsos, vtx, *thePropagator);
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::extrapolate (const FreeTrajectoryState& fts,
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const GlobalPoint& vtx,
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const Propagator& p) const
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{
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//
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// set propagator for bidirectional propagation
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//
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SetPropagationDirection setter(p,anyDirection);
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return doExtrapolation(fts,vtx,p);
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::extrapolate (const TrajectoryStateOnSurface tsos,
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const GlobalPoint& vtx,
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const Propagator& p) const
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{
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if ( !tsos.isValid() ) return tsos;
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//
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// set propagator for bidirectional propagation
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//
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SetPropagationDirection setter(p,anyDirection);
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return doExtrapolation(tsos,vtx,p);
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::doExtrapolation (const TrajectoryStateOnSurface tsos,
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const GlobalPoint& vtx,
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const Propagator& p) const
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{
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//
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// Compute tip surface
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//
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if (fabs(tsos.freeState()->transverseCurvature())<1.E-6){
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LogDebug("TransverseImpactPointExtrapolator")<< "negligeable curvature: using a trick to extrapolate:\n"<<tsos;
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//0T field probably
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//x is perpendicular to the momentum
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GlobalVector xLocal = GlobalVector(-tsos.globalMomentum().y(),tsos.globalMomentum().x(),0).unit();
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//y along global Z
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GlobalVector yLocal(0.,0.,1.);
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//z accordingly
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GlobalVector zLocal(xLocal.cross(yLocal));
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Surface::PositionType origin(vtx);
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Surface::RotationType rotation(xLocal,yLocal,zLocal);
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ReferenceCountingPointer<BoundPlane> surface = PlaneBuilder().plane(origin,rotation);
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return p.propagate(*tsos.freeState(),*surface);
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}else{
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ReferenceCountingPointer<BoundPlane> surface =
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tipSurface(tsos.globalPosition(),tsos.globalMomentum(),
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1./tsos.transverseCurvature(),vtx);
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//
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// propagate
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//
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return p.propagate(tsos,*surface);
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}
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}
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TrajectoryStateOnSurface
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TransverseImpactPointExtrapolator::doExtrapolation (const FreeTrajectoryState& fts,
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const GlobalPoint& vtx,
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const Propagator& p) const
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{
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//
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// Compute tip surface
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//
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if (fabs(fts.transverseCurvature())<1.E-6){
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LogDebug("TransverseImpactPointExtrapolator")<< "negligeable curvature: using a trick to extrapolate:\n"<<fts;
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//0T field probably
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//x is perpendicular to the momentum
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GlobalVector xLocal = GlobalVector(-fts.momentum().y(),fts.momentum().x(),0).unit();
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//y along global Z
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GlobalVector yLocal(0.,0.,1.);
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//z accordingly
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GlobalVector zLocal(xLocal.cross(yLocal));
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Surface::PositionType origin(vtx);
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Surface::RotationType rotation(xLocal,yLocal,zLocal);
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ReferenceCountingPointer<BoundPlane> surface = PlaneBuilder().plane(origin,rotation);
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return p.propagate(fts,*surface);
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}else{
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ReferenceCountingPointer<BoundPlane> surface =
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tipSurface(fts.position(),fts.momentum(),
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1./fts.transverseCurvature(),vtx);
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//
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// propagate
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//
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return p.propagate(fts,*surface);
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}
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}
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ReferenceCountingPointer<BoundPlane>
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TransverseImpactPointExtrapolator::tipSurface (const GlobalPoint& position,
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const GlobalVector& momentum,
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const double& signedTransverseRadius,
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const GlobalPoint& vertex) const
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{
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LogDebug("TransverseImpactPointExtrapolator")<< position<<"\n"
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<<momentum<<"\n"
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<<"signedTransverseRadius : "<<signedTransverseRadius<<"\n"
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<<vertex;
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typedef Point2DBase<double,GlobalTag> PositionType2D;
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typedef Vector2DBase<double,GlobalTag> DirectionType2D;
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PositionType2D x0(position.x(),position.y());
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DirectionType2D t0(-momentum.y(),momentum.x());
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t0 = t0/t0.mag();
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PositionType2D xc(x0+signedTransverseRadius*t0);
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DirectionType2D vtxDirection(xc.x()-vertex.x(),xc.y()-vertex.y());
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double vtxDistance = vtxDirection.mag();
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Surface::PositionType origin(vertex);
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GlobalVector xLocal(vtxDirection.x()/vtxDistance,
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vtxDirection.y()/vtxDistance,
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0.);
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if ( vtxDistance<fabs(signedTransverseRadius) ) {
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LogDebug("TransverseImpactPointExtrapolator")<<"Inverting the x axis.";
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xLocal = -xLocal;
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}
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GlobalVector yLocal(0.,0.,1.);
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GlobalVector zLocal(xLocal.cross(yLocal));
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if ( zLocal.dot(momentum)<0. ) {
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LogDebug("TransverseImpactPointExtrapolator")<<"Inverting the y,z frame.";
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yLocal = -yLocal;
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zLocal = -zLocal;
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}
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Surface::RotationType rotation(xLocal,yLocal,zLocal);
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LogDebug("TransverseImpactPointExtrapolator")<<"plane center: "<<origin<<"\n"
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<<"plane rotation axis:\n"
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<<xLocal<<"\n"
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<<yLocal<<"\n"
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<<zLocal<<"\n"
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<<"x0: "<<x0<<"\n"
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<<"t0: "<<t0<<"\n"
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<<"xc: "<<xc<<"\n"
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<<"vtxDirection: "<<vtxDirection;
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return PlaneBuilder().plane(origin,rotation);
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}
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