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// $Id: HitDropper.cc,v 1.3 2009/02/06 16:08:44 mrudolph Exp $
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#include "MitEdm/Producers/interface/HitDropper.h"
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#include "DataFormats/TrackingRecHit/interface/InvalidTrackingRecHit.h"
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#include "DataFormats/TrajectorySeed/interface/PropagationDirection.h"
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#include "TrackingTools/GeomPropagators/interface/HelixArbitraryPlaneCrossing.h"
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#include "TrackingTools/GeomPropagators/interface/StraightLinePlaneCrossing.h"
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using namespace edm;
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using namespace mitedm;
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//--------------------------------------------------------------------------------------------------
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reco::HitPattern HitDropper::CorrectedHits(const reco::TransientTrack *tTrack,
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const ThreeVector &vtxPos) const
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{
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// Return reco::HitPattern structure for the given track with all hits occuring before vtxPos
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// on the track (relative to the primary vertex if given) removed.
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// This version of the function uses an iterative helix-plane intersector and does not (yet)
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// take into account the uncertainties in vertex position.
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const GlobalPoint vtxPoint(vtxPos.x(),vtxPos.y(),vtxPos.z());
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const TrajectoryStateClosestToPoint vtxTSCP = tTrack->trajectoryStateClosestToPoint(vtxPoint);
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reco::HitPattern hitPattern;
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int nHits = 0;
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for (uint hi=0; hi<tTrack->recHitsSize(); ++hi) {
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const TrackingRecHit *hit = tTrack->recHit(hi).get();
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DetId geoId = hit->geographicalId();
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if(geoId == uint32_t(0)) continue;
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const GeomDet *det = trackerGeo_->idToDet(geoId);
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HelixArbitraryPlaneCrossing crossing(HelixPlaneCrossing::PositionType(vtxTSCP.theState().position()),
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HelixPlaneCrossing::DirectionType(vtxTSCP.theState().momentum()),
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vtxTSCP.theState().transverseCurvature(),
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anyDirection);
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std::pair<bool,double> crossResult = crossing.pathLength(det->surface());
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if ( crossResult.first && crossResult.second >= 0 ) {
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hitPattern.set(*hit,nHits);
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nHits++;
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}
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}
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return hitPattern;
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}
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//--------------------------------------------------------------------------------------------------
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reco::HitPattern HitDropper::CorrectedHits(const reco::Track *track,
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const ThreeVector &vtxPos) const
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{
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// Build the transient track and then return the corrected HitPattern.
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reco::TransientTrack tTrack = builder_->build(track);
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return CorrectedHits(&tTrack, vtxPos);
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}
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//--------------------------------------------------------------------------------------------------
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reco::HitPattern HitDropper::CorrectedHits(const reco::Track *track,
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const ThreeVector &vtxPos,
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const ThreeVector &trkMom,
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Double_t lxyError,
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Double_t lzError,
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Double_t sigmaTolerance) const
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{
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// Return reco::HitPattern structure for the given track with all hits occuring before vtxPos
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// on the track (relative to the primary vertex if given) removed.
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// This version of the function determines this completely analytically, and taking the
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// vertex position uncertainty into account, which might be important for particles which decay
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// within a tracker layer.
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const StraightLinePlaneCrossing::PositionType vtxPosition(vtxPos);
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const StraightLinePlaneCrossing::DirectionType trkMomentum(trkMom);
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StraightLinePlaneCrossing crossing(vtxPosition,trkMomentum,anyDirection);
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reco::HitPattern hitPattern;
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int nHits = 0;
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for (uint hi=0; hi<track->recHitsSize(); ++hi) {
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const TrackingRecHit *hit = track->recHit(hi).get();
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DetId geoId = hit->geographicalId();
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if(geoId == uint32_t(0)) continue;
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const GeomDet *det = trackerGeo_->idToDet(geoId);
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//calculate intersection of straight line with plane
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const StraightLinePlaneCrossing::PositionType crossPosition = crossing.position(det->surface()).second;
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const ThreeVector crossPos(crossPosition.x(), crossPosition.y(), crossPosition.z());
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const ThreeVector delta = crossPos - vtxPos;
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Double_t lengthOverSigma = 0;
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//calculate distance between vertex and approximate hit position, projected into
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//the appropriate plane/axis and compared to the uncertainty in vertex position
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//in that plane/axis
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if (IsBarrel(det)) {
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const ThreeVector trkMomXY(trkMom.x(), trkMom.y(), 0.0);
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Double_t deltaXY = delta.Dot(trkMomXY)/trkMomXY.R();
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lengthOverSigma = deltaXY/lxyError;
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}
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else if (IsDisk(det)) {
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Double_t deltaZ = delta.z()*trkMom.z()/fabs(trkMom.z());
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lengthOverSigma = deltaZ/lzError;
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}
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else
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throw edm::Exception(edm::errors::Configuration, "HitDropper::CorrectedHits\n")
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<< "Error! Detector element not in a valid barrel or disk layer." << std::endl;
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//add the hit only if it is after the vertex, allowing for some uncertainty in the vertex position
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if ( lengthOverSigma>(-sigmaTolerance) ) {
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hitPattern.set(*hit,nHits);
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nHits++;
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}
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}
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return hitPattern;
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}
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