DTSegmentCleaner.cc

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/* This Class Header */
#include "RecoLocalMuon/DTSegment/src/DTSegmentCleaner.h"

/* Collaborating Class Header */
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

/* C++ Headers */
using namespace std;

/* ====================================================================== */

/* Constructor */ 
DTSegmentCleaner::DTSegmentCleaner(const edm::ParameterSet& pset) {
  nSharedHitsMax = pset.getParameter<int>("nSharedHitsMax");

  nUnSharedHitsMin = pset.getParameter<int>("nUnSharedHitsMin");

  segmCleanerMode = pset.getParameter<int>("segmCleanerMode");
 
  if((segmCleanerMode!=1)&&(segmCleanerMode!=2)&&(segmCleanerMode!=3))
    edm::LogError("Muon|RecoLocalMuon|DTSegmentCleaner")
      << "Wrong segmCleanerMode! It must be 1,2 or 3. The default is 1";
}

/* Destructor */ 
DTSegmentCleaner::~DTSegmentCleaner() {
}

/* Operations */ 
vector<DTSegmentCand*> DTSegmentCleaner::clean(const std::vector<DTSegmentCand*>& inputCands) const {
  if (inputCands.size()<2) return inputCands;
  //cout << "[DTSegmentCleaner] # of candidates: " << inputCands.size() << endl;
  vector<DTSegmentCand*> result = solveConflict(inputCands);

  //cout << "[DTSegmentCleaner] to ghostbuster: " << result.size() << endl;
  result = ghostBuster(result);

  return result;
}

vector<DTSegmentCand*> DTSegmentCleaner::solveConflict(const std::vector<DTSegmentCand*>& inputCands) const {
  vector<DTSegmentCand*> result;

  vector<DTSegmentCand*> ghosts;


  for (vector<DTSegmentCand*>::const_iterator cand=inputCands.begin();
       cand!=inputCands.end(); ++cand) {
    for (vector<DTSegmentCand*>::const_iterator cand2 = cand+1 ; cand2!=inputCands.end() ; ++cand2) {

      DTSegmentCand::AssPointCont confHits=(*cand)->conflictingHitPairs(*(*cand2));
      
      if (!confHits.empty()) {
    if((confHits.size())==((*cand)->nHits()) && (confHits.size())==((*cand2)->nHits())
       && (fabs((*cand)->chi2()-(*cand2)->chi2())<0.1)) { // cannot choose on the basis of # of hits or chi2

      if(segmCleanerMode == 2) { // mode 2: choose on the basis of the angle

        DTSegmentCand* badCand = nullptr;
        if((*cand)->superLayer()->id().superlayer() != 2) { // we are in the phi view

          LocalVector dir1 = (*cand)->direction();
          LocalVector dir2 = (*cand2)->direction();
          float phi1=(atan((dir1.x())/(dir1.z())));
          float phi2=(atan((dir2.x())/(dir2.z())));

          badCand = (fabs(phi1) > fabs(phi2)) ? (*cand) : (*cand2);

        } else {  // we are in the theta view: choose the most pointing one

          GlobalPoint IP;

          GlobalVector cand1GlobDir = (*cand)->superLayer()->toGlobal((*cand)->direction());
          GlobalPoint cand1GlobPos =  (*cand)->superLayer()->toGlobal((*cand)->position());
          GlobalVector cand1GlobVecIP = cand1GlobPos-IP;
          float DAlpha1 = fabs(cand1GlobDir.theta()-cand1GlobVecIP.theta());


          GlobalVector cand2GlobDir = (*cand2)->superLayer()->toGlobal((*cand2)->direction());
          GlobalPoint cand2GlobPos = (*cand2)->superLayer()->toGlobal((*cand2)->position());
          GlobalVector cand2GlobVecIP = cand2GlobPos-IP;
          float DAlpha2 = fabs(cand2GlobDir.theta()-cand2GlobVecIP.theta());

          badCand = (DAlpha1 > DAlpha2) ? (*cand) : (*cand2);
        }

        for (DTSegmentCand::AssPointCont::const_iterator cHit=confHits.begin() ;
         cHit!=confHits.end(); ++cHit) {
          badCand->removeHit(*cHit);
        }
    
      } else { // mode 3: keep both candidates
        continue;
      }

    } else { // mode 1: take > # hits or best chi2
      //cout << " Choose based on hits/chi2. " << endl << (**cand) << " vs " << (**cand2) << endl;
      
      // if one segment is in-time and the other not then keep both
      if (((*cand)->t0()*(*cand2)->t0()!=0) || ((*cand)->t0()==(*cand2)->t0())) {
        DTSegmentCand* badCand = (**cand) < (**cand2) ? (*cand) : (*cand2);
        //cout << " Remove hits in " << (*badCand) << endl;
        for (DTSegmentCand::AssPointCont::const_iterator cHit=confHits.begin() ;
             cHit!=confHits.end(); ++cHit) badCand->removeHit(*cHit);
      }       
    }

      }
    }
  }

  vector<DTSegmentCand*>::const_iterator cand=inputCands.begin();
  while ( cand < inputCands.end() ) {
    if ((*cand)->good()) result.push_back(*cand); 
    else {
      vector<DTSegmentCand*>::const_iterator badCand=cand;
      delete *badCand;
    }
    ++cand;
  }
  return result;
}

vector<DTSegmentCand*> 
DTSegmentCleaner::ghostBuster(const std::vector<DTSegmentCand*>& inputCands) const {
  vector<DTSegmentCand*> ghosts;
  for (vector<DTSegmentCand*>::const_iterator cand=inputCands.begin();
       cand!=inputCands.end(); ++cand) {
    for (vector<DTSegmentCand*>::const_iterator cand2=cand+1;
         cand2!=inputCands.end(); ++cand2) {
      unsigned int nSharedHits=(*cand)->nSharedHitPairs(*(*cand2));
      //       << " (first or second) " << ((**cand)<(**cand2)) << endl;
      if ((nSharedHits==((*cand)->nHits())) && (nSharedHits==((*cand2)->nHits()))
          &&(fabs((*cand)->chi2()-(*cand2)->chi2())<0.1)
          &&(segmCleanerMode==3))
      {
        continue;
      }
      
      if (((*cand)->nHits()==3 || (*cand2)->nHits()==3) 
          &&(fabs((*cand)->chi2()-(*cand2)->chi2())<0.0001))
      {
        continue;
      }

      // if one segment is in-time and the other not then keep both
      if (((*cand2)->nHits()==(*cand)->nHits()) && ((*cand)->t0()*(*cand2)->t0()==0) && ((*cand)->t0()!=(*cand2)->t0()))
      {
        continue;
      }

      // remove the worst segment if too many shared hits or too few unshared
      if ((int)nSharedHits >= nSharedHitsMax ||
          (int)((*cand)->nHits()-nSharedHits)<=nUnSharedHitsMin ||
          (int)((*cand2)->nHits()-nSharedHits)<=nUnSharedHitsMin) {

        if ((**cand)<(**cand2)) {
          ghosts.push_back(*cand);
        }
        else {
          ghosts.push_back(*cand2);
        }
        continue;
      }

    }
  }

  vector<DTSegmentCand*> result;
  for (vector<DTSegmentCand*>::const_iterator cand=inputCands.begin();
       cand!=inputCands.end(); ++cand) {
    bool isGhost=false;
    for (vector<DTSegmentCand*>::const_iterator ghost=ghosts.begin();
         ghost!=ghosts.end(); ++ghost) {
      if ((*cand)==(*ghost)) {
        isGhost=true;
        break;
      }
    }
    if (!isGhost) result.push_back(*cand);
    else delete *cand;
  }
  // cout << "No Ghosts ------" << endl;
  // for (vector<DTSegmentCand*>::iterator cand=result.begin();
  //      cand!=result.end(); ++cand) {
  //   cout << "cand " << *cand << " nH " <<(*cand)->nHits() << " chi2 " << (*cand)->chi2() << endl;
  // }
  // cout << "----------------" << endl;

  return result;
}