GenericTripletGenerator.cc

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#include "RecoTracker/SpecialSeedGenerators/interface/GenericTripletGenerator.h"
#include "RecoTracker/TkSeedGenerator/interface/FastCircle.h"
typedef SeedingHitSet::ConstRecHitPointer SeedingHit;


#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include <map>


GenericTripletGenerator::GenericTripletGenerator(const edm::ParameterSet& conf, edm::ConsumesCollector& iC):
  theSeedingLayerToken(iC.consumes<SeedingLayerSetsHits>(conf.getParameter<edm::InputTag>("LayerSrc"))) {
    edm::LogInfo("CtfSpecialSeedGenerator|GenericTripletGenerator") << "Constructing GenericTripletGenerator";
} 


const OrderedSeedingHits& GenericTripletGenerator::run(const TrackingRegion& region,
                                                 const edm::Event& e,
                                                 const edm::EventSetup& es){
    hitTriplets.clear();
    hitTriplets.reserve(0);
    edm::Handle<SeedingLayerSetsHits> hlayers;
    e.getByToken(theSeedingLayerToken, hlayers);
    const SeedingLayerSetsHits& layers = *hlayers;
        if(layers.numberOfLayersInSet() != 3)
          throw cms::Exception("CtfSpecialSeedGenerator") << "You are using " << layers.numberOfLayersInSet() <<" layers in set instead of 3 ";
    std::map<float, OrderedHitTriplet> radius_triplet_map;
        for(SeedingLayerSetsHits::SeedingLayerSet ls: layers) {
        auto innerHits  = region.hits(es, ls[0]);
        //std::cout << "innerHits.size()=" << innerHits.size() << std::endl;
        auto middleHits = region.hits(es, ls[1]);
        //std::cout << "middleHits.size()=" << middleHits.size() << std::endl;
        auto outerHits  = region.hits(es, ls[2]);
        //std::cout << "outerHits.size()=" << outerHits.size() << std::endl;
        //std::cout << "trying " << innerHits.size()*middleHits.size()*outerHits.size() << " combinations "<<std::endl;
        for (auto iOuterHit = outerHits.begin(); iOuterHit != outerHits.end(); iOuterHit++){
          for (auto iMiddleHit = middleHits.begin(); iMiddleHit != middleHits.end(); iMiddleHit++){
            for (auto iInnerHit = innerHits.begin(); iInnerHit != innerHits.end(); iInnerHit++){
              //GlobalPoint innerpos  = ls[0].hitBuilder()->build(&(**iInnerHit))->globalPosition();
              //GlobalPoint middlepos = ls[1].hitBuilder()->build(&(**iMiddleHit))->globalPosition();
              //GlobalPoint outerpos  = ls[2].hitBuilder()->build(&(**iOuterHit))->globalPosition();
              //FastCircle circle(innerpos,
              //          middlepos,
              //                  outerpos);
              //do a first check on the radius of curvature to reduce the combinatorics 
              OrderedHitTriplet oht(&(**iInnerHit),&(**iMiddleHit),&(**iOuterHit));
              std::pair<bool,float> val_radius = qualityFilter(oht,radius_triplet_map,ls);
              if (val_radius.first){
            //if (circle.rho() > 200 || circle.rho() == 0) { //0 radius means straight line
            //hitTriplets.push_back(OrderedHitTriplet(*iInnerHit,
            //                  *iMiddleHit,
            //                  *iOuterHit));
            hitTriplets.push_back(oht);
            radius_triplet_map.insert(std::make_pair(val_radius.second,oht));
              }
            }
          }
        }
        }
    //std::cout << "ending with " << hitTriplets.size() << " triplets" << std::endl;
    return hitTriplets;
}

std::pair<bool,float> GenericTripletGenerator::qualityFilter(const OrderedHitTriplet& oht, 
                                 const std::map<float, OrderedHitTriplet>& map,
                                 const SeedingLayerSetsHits::SeedingLayerSet& ls) const{
  //first check the radius
  GlobalPoint innerpos  = oht.inner()->globalPosition();
  GlobalPoint middlepos = oht.middle()->globalPosition();
    GlobalPoint outerpos  = oht.outer()->globalPosition();
    std::vector<const TrackingRecHit*> ohttrh;
    ohttrh.push_back(&(*(oht.inner()))); ohttrh.push_back(&(*(oht.middle()))); ohttrh.push_back(&(*(oht.outer()))); 
    std::vector<const TrackingRecHit*>::const_iterator ioht;
    //now chech that the change in phi is reasonable. the limiting angular distance is the one in case 
    //one of the two points is a tangent point.
    float limit_phi_distance1 = sqrt((middlepos.x()-outerpos.x())*(middlepos.x()-outerpos.x()) + 
                     (middlepos.y()-outerpos.y())*(middlepos.y()-outerpos.y()))/middlepos.mag();//actually this is the tangent of the limiting angle         
    float limit_phi_distance2 = sqrt((middlepos.x()-innerpos.x())*(middlepos.x()-innerpos.x()) +
                     (middlepos.y()-innerpos.y())*(middlepos.y()-innerpos.y()))/innerpos.mag();
    //if (fabs(tan(outerpos.phi()-middlepos.phi()))>limit_phi_distance1 || 
    //    fabs(tan(innerpos.phi()-middlepos.phi()))>limit_phi_distance2) {
    if (fabs(outerpos.phi()-middlepos.phi())>fabs(atan(limit_phi_distance1)) ||
            fabs(innerpos.phi()-middlepos.phi())>fabs(atan(limit_phi_distance2)) ) {    
      //std::cout << "rejected because phi" << std::endl;
      return std::make_pair(false, 0.);
    }
    //should we add a control on the r-z plane too?
    /*
    //now check that there is no big change in the r-z projection
    float dz1 = outerpos.z()-middlepos.z();
    float dr1 = sqrt(outerpos.x()*outerpos.x()+outerpos.y()*outerpos.y())-
    sqrt(middlepos.x()*middlepos.x()+middlepos.y()*middlepos.y());      
    float dz2 = middlepos.z()-innerpos.z(); 
    float dr2 = sqrt(middlepos.x()*middlepos.x()+middlepos.y()*middlepos.y())-
    sqrt(innerpos.x()*innerpos.x()+innerpos.y()*innerpos.y());
    float tan1 = dz1/dr1;
    float tan2 = dz2/dr2;
    //how much should we allow? should we make it configurable?
    if (fabs(tan1-tan2)/tan1>0.5){
    //std::cout << "rejected because z" << std::endl;
    return std::make_pair(false, 0.);   
    }
    */
    //now check the radius is not too small
    FastCircle circle(innerpos, middlepos, outerpos);
    if (circle.rho() < 200 && circle.rho() != 0) return std::make_pair(false, circle.rho()); //to small radius  
    //now check if at least 2 hits are shared with an existing triplet
    //look for similar radii in the map
    std::map<float, OrderedHitTriplet>::const_iterator lower_bound = map.lower_bound((1-0.01)*circle.rho());
    std::map<float, OrderedHitTriplet>::const_iterator upper_bound = map.upper_bound((1+0.01)*circle.rho());    
    std::map<float, OrderedHitTriplet>::const_iterator iter;
    for (iter = lower_bound; iter != upper_bound && iter->first <= upper_bound->first; iter++){
      int shared=0;
      std::vector<const TrackingRecHit*> curtrh;
      curtrh.push_back(&*(iter->second.inner()));curtrh.push_back(&*(iter->second.middle()));curtrh.push_back(&*(iter->second.outer()));
      std::vector<const TrackingRecHit*>::const_iterator curiter;
      for (curiter = curtrh.begin(); curiter != curtrh.end(); curiter++){
        for (ioht = ohttrh.begin(); ioht != ohttrh.end(); ioht++){
          if ((*ioht)->geographicalId()==(*curiter)->geographicalId() && 
          ((*ioht)->localPosition()-(*curiter)->localPosition()).mag()<1e-5) shared++;  
        }
      }
      if (shared>1) return std::make_pair(false, circle.rho()); 
    }   
    
    return std::make_pair(true,circle.rho());
}