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00001 #include "RecoTracker/TkSeedGenerator/interface/SeedFromConsecutiveHitsStraightLineCreator.h" 00002 00003 #include "FWCore/MessageLogger/interface/MessageLogger.h" 00004 #include "MagneticField/Engine/interface/MagneticField.h" 00005 #include "MagneticField/Records/interface/IdealMagneticFieldRecord.h" 00006 #include "FWCore/Framework/interface/ESHandle.h" 00007 #include "FWCore/Framework/interface/EventSetup.h" 00008 #include "RecoTracker/TkTrackingRegions/interface/TrackingRegion.h" 00009 00010 00011 GlobalTrajectoryParameters SeedFromConsecutiveHitsStraightLineCreator::initialKinematic( 00012 const SeedingHitSet & hits, 00013 const TrackingRegion & region, 00014 const edm::EventSetup& es) const 00015 { 00016 GlobalTrajectoryParameters kine; 00017 00018 const TransientTrackingRecHit::ConstRecHitPointer& tth1 = hits[0]; 00019 const TransientTrackingRecHit::ConstRecHitPointer& tth2 = hits[1]; 00020 00021 const GlobalPoint& vertexPos = region.origin(); 00022 edm::ESHandle<MagneticField> bfield; 00023 es.get<IdealMagneticFieldRecord>().get(bfield); 00024 00025 // Assume initial state is straight line passing through beam spot 00026 // with direction given by innermost two seed hits (with big uncertainty) 00027 GlobalVector initMomentum(tth2->globalPosition() - tth1->globalPosition()); 00028 double rescale = 1000./initMomentum.perp(); 00029 initMomentum *= rescale; // set to approximately infinite momentum 00030 TrackCharge q = 1; // irrelevant, since infinite momentum 00031 kine = GlobalTrajectoryParameters(vertexPos, initMomentum, q, &*bfield); 00032 00033 return kine; 00034 } 00035
1.7.3