HitPairGeneratorFromLayerPairForPhotonConversion.cc

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#include "HitPairGeneratorFromLayerPairForPhotonConversion.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

#include "TrackingTools/DetLayers/interface/DetLayer.h"
#include "TrackingTools/DetLayers/interface/BarrelDetLayer.h"
#include "TrackingTools/DetLayers/interface/ForwardDetLayer.h"

#include "RecoTracker/TkTrackingRegions/interface/HitRZCompatibility.h"
#include "RecoTracker/TkTrackingRegions/interface/TrackingRegion.h"
#include "RecoTracker/TkTrackingRegions/interface/TrackingRegionBase.h"
#include "RecoTracker/TkHitPairs/interface/OrderedHitPairs.h"
#include "RecoTracker/TkHitPairs/src/InnerDeltaPhi.h"

#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"

using namespace GeomDetEnumerators;
using namespace std;
#include "RecoTracker/TkMSParametrization/interface/PixelRecoUtilities.h"

// #define mydebug_Seed

typedef PixelRecoRange<float> Range;

namespace {
 template<class T> inline T sqr( T t) {return t*t;}
}


#include "TrackingTools/TransientTrackingRecHit/interface/TransientTrackingRecHitBuilder.h"
#include "TrackingTools/Records/interface/TransientRecHitRecord.h"
#include "Geometry/TrackerGeometryBuilder/interface/TrackerGeometry.h"
#include "RecoTracker/Record/interface/TrackerRecoGeometryRecord.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "DataFormats/Math/interface/deltaPhi.h"

HitPairGeneratorFromLayerPairForPhotonConversion::HitPairGeneratorFromLayerPairForPhotonConversion(
                                 unsigned int inner,
                                 unsigned int outer,
                                 LayerCacheType* layerCache,
                                 unsigned int nSize,
                                 unsigned int max)
  :
    theLayerCache(*layerCache), theOuterLayer(outer), theInnerLayer(inner), theMaxElement(max) {

}

void HitPairGeneratorFromLayerPairForPhotonConversion::hitPairs(const ConversionRegion& convRegion,
                                const TrackingRegion & region, OrderedHitPairs & result,
                                const edm::Event& event, const edm::EventSetup& es)
{
 auto oldSize = result.size();
 auto maxNum = result.size()+theMaxElement;

#ifdef mydebug_Seed
  ss.str("");
#endif

  typedef OrderedHitPair::InnerRecHit InnerHit;
  typedef OrderedHitPair::OuterRecHit OuterHit;
  typedef RecHitsSortedInPhi::Hit Hit;

  Layer innerLayerObj = innerLayer();
  Layer outerLayerObj = outerLayer();

#ifdef mydebug_Seed
  ss << "In " << innerLayerObj.name() << " Out " << outerLayerObj.name() << std::endl;
#endif

  if(!checkBoundaries(*innerLayerObj.detLayer(),convRegion,40.,60.)) return; //FIXME, the maxSearchR(Z) are not optimized
  if(!checkBoundaries(*outerLayerObj.detLayer(),convRegion,50.,60.)) return; //FIXME, the maxSearchR(Z) are not optimized

  /*get hit sorted in phi for each layer: NB: doesn't apply any region cut*/
  const RecHitsSortedInPhi & innerHitsMap = theLayerCache(innerLayerObj, region, event, es);
  if (innerHitsMap.empty()) return;
 
  const RecHitsSortedInPhi& outerHitsMap = theLayerCache(outerLayerObj, region, event, es);
  if (outerHitsMap.empty()) return;
  /*----------------*/

  /*This object will check the compatibility of the his in phi among the two layers. */
  //InnerDeltaPhi deltaPhi(innerLayerObj.detLayer(), region, es);

  static const float nSigmaRZ = std::sqrt(12.f);
  //  static const float nSigmaPhi = 3.f;
  vector<RecHitsSortedInPhi::Hit> innerHits, outerHits;
  float outerPhimin, outerPhimax;
  float innerPhimin, innerPhimax;

  /*Getting only the Hits in the outer layer that are compatible with the conversion region*/
  if(!getPhiRange(outerPhimin,outerPhimax,*outerLayerObj.detLayer(),convRegion,es)) return;
  outerHitsMap.hits( outerPhimin, outerPhimax, outerHits);

#ifdef mydebug_Seed
  ss << "\tophimin, ophimax " << outerPhimin << " " << outerPhimax << std::endl;
#endif

  /* loop on outer hits*/
  for (vector<RecHitsSortedInPhi::Hit>::const_iterator oh = outerHits.begin(); oh!= outerHits.end(); ++oh) { 
    RecHitsSortedInPhi::Hit ohit = (*oh);
#ifdef mydebug_Seed
    GlobalPoint oPos = ohit->globalPosition();  
    
    ss << "\toPos " << oPos << " r " << oPos.perp() << " phi " << oPos.phi() <<  " cotTheta " << oPos.z()/oPos.perp() << std::endl;
#endif

    /*Check the compatibility of the ohit with the eta of the seeding track*/
    if(checkRZCompatibilityWithSeedTrack(ohit,*outerLayerObj.detLayer(),convRegion)) continue;

    /*  
    //Do I need this? it uses a compatibility that probably I wouldn't 
    //Removing for the time being

    PixelRecoRange<float> phiRange = deltaPhi( oPos.perp(), oPos.phi(), oPos.z(), nSigmaPhi*(ohit->errorGlobalRPhi()));    
    if (phiRange.empty()) continue;
    */

    const HitRZCompatibility *checkRZ = region.checkRZ(innerLayerObj.detLayer(), ohit, es);
    if(!checkRZ) {
#ifdef mydebug_Seed
      ss << "*******\nNo valid checkRZ\n*******" << std::endl;
#endif
      continue;
    }
    
    /*Get only the inner hits compatible with the conversion region*/
    innerHits.clear();
    if(!getPhiRange(innerPhimin,innerPhimax,*innerLayerObj.detLayer(),convRegion,es)) continue;
    innerHitsMap.hits(innerPhimin, innerPhimax, innerHits);

#ifdef mydebug_Seed
    ss << "\tiphimin, iphimax " << innerPhimin << " " << innerPhimax << std::endl;
#endif    

    /*Loop on inner hits*/
    for ( vector<RecHitsSortedInPhi::Hit>::const_iterator ih=innerHits.begin(), ieh = innerHits.end(); ih < ieh; ++ih) {  
      GlobalPoint innPos = (*ih)->globalPosition();
      

#ifdef mydebug_Seed
      ss << "\tinnPos " << innPos <<  " r " << innPos.perp() << " phi " << innPos.phi() << " cotTheta " << innPos.z()/innPos.perp() <<  std::endl;
#endif

      /*Check the compatibility of the ohit with the eta of the seeding track*/
      if(checkRZCompatibilityWithSeedTrack(*ih,*innerLayerObj.detLayer(),convRegion)) continue;
      
      float r_reduced = std::sqrt( sqr(innPos.x()-region.origin().x())+sqr(innPos.y()-region.origin().y()));
      Range allowed;
      Range hitRZ;
      if (innerLayerObj.detLayer()->location() == barrel) {
        allowed = checkRZ->range(r_reduced);
        float zErr = nSigmaRZ * (*ih)->errorGlobalZ();
        hitRZ = Range(innPos.z()-zErr, innPos.z()+zErr);
      } else {
        allowed = checkRZ->range(innPos.z());
        float rErr = nSigmaRZ * (*ih)->errorGlobalR();
        hitRZ = Range(r_reduced-rErr, r_reduced+rErr);
      }
      Range crossRange = allowed.intersection(hitRZ);

#ifdef mydebug_Seed      
      ss 
    << "\n\t\t allowed Range " << allowed.min() << " \t, " << allowed.max() 
    << "\n\t\t hitRz   Range " << hitRZ.min()   << " \t, " << hitRZ.max() 
    << "\n\t\t Cross   Range " << crossRange.min()   << " \t, " << crossRange.max() 
    << "\n\t\t the seed track has origin " << convRegion.convPoint() << " \t cotTheta " << convRegion.cotTheta() 
    << std::endl;
#endif
      
      if (! crossRange.empty() ) {
#ifdef mydebug_Seed      
      ss 
    << "\n\t\t !!!!ACCEPTED!!! \n\n";
#endif
    if (theMaxElement!=0 && result.size() >= maxNum ){
      result.resize(oldSize);
#ifdef mydebug_Seed      
      edm::LogError("TooManySeeds")<<"number of pairs exceed maximum, no pairs produced";
#endif
      delete checkRZ;

#ifdef mydebug_Seed
      std::cout << ss.str();
#endif
      return;
    }
        result.push_back( OrderedHitPair( *ih, ohit) );
      }
    }
    delete checkRZ;
  }

#ifdef mydebug_Seed
  std::cout << ss.str();
#endif
}


float HitPairGeneratorFromLayerPairForPhotonConversion::getLayerRadius(const DetLayer& layer){
  if (layer.location() == GeomDetEnumerators::barrel){ 
    const BarrelDetLayer& bl = static_cast<const BarrelDetLayer&>(layer); 
    float rLayer = bl.specificSurface().radius(); 
    
    // the maximal delta phi will be for the innermost hits
    float theThickness = layer.surface().bounds().thickness();
    return rLayer + 0.5f*theThickness;
  }

  //Fixme
  return 0;
}

float HitPairGeneratorFromLayerPairForPhotonConversion::getLayerZ(const DetLayer& layer){
  if (layer.location() == GeomDetEnumerators::endcap){ 
    float layerZ = layer.position().z();
    float theThickness = layer.surface().bounds().thickness();
    float layerZmax = layerZ > 0 ? layerZ+0.5f*theThickness: layerZ-0.5f*theThickness;
    return layerZmax;
  }else{
    //Fixme
    return 0;
  }
}
bool HitPairGeneratorFromLayerPairForPhotonConversion::checkBoundaries(const DetLayer& layer,const ConversionRegion& convRegion,float maxSearchR, float maxSearchZ){

  if(layer.location() == GeomDetEnumerators::barrel){

    float minZEndCap=130;
    if(fabs(convRegion.convPoint().z()) > minZEndCap){
#ifdef mydebug_Seed
      ss << "\tthe conversion seems to be in the endcap. Zconv " << convRegion.convPoint().z() << std::endl;
      std::cout << ss.str();
#endif
      return false;
    }
      
    float R=getLayerRadius(layer);
    
    if(convRegion.convPoint().perp()>R){
#ifdef mydebug_Seed
      ss << "\tthis layer is before the conversion : R layer " << R << " [ Rconv " << convRegion.convPoint().perp() << " Zconv " << convRegion.convPoint().z()<< std::endl;
      std::cout << ss.str();
#endif
      return false;
    }
    
    if(R - convRegion.convPoint().perp() > maxSearchR ){
#ifdef mydebug_Seed
      ss << "\tthis layer is far from the conversion more than cut " << maxSearchR << " cm. R layer " << R << " [ Rconv " << convRegion.convPoint().perp() << " Zconv " << convRegion.convPoint().z()<< std::endl;
      std::cout << ss.str();
#endif
      return false;
    }
    
  }else if (layer.location() == GeomDetEnumerators::endcap){
    
    float Z=getLayerZ(layer);
    if(
       (convRegion.convPoint().z()>0 && convRegion.convPoint().z()>Z)
       ||
       (convRegion.convPoint().z()<0 && convRegion.convPoint().z()<Z)
       ) {
#ifdef mydebug_Seed
      ss << "\tthis layer is before the conversion : Z layer " << Z << " [ Rconv " << convRegion.convPoint().perp()<< " Zconv " << convRegion.convPoint().z() << std::endl;
      std::cout << ss.str();
#endif
      return false;
    }    

     
    if(fabs(Z - convRegion.convPoint().z()) > maxSearchZ ){
#ifdef mydebug_Seed
      ss << "\tthis layer is far from the conversion more than cut " << maxSearchZ << " cm. Z layer " << Z << " [ Rconv " << convRegion.convPoint().perp()<< " Zconv " << convRegion.convPoint().z() << std::endl;
      std::cout << ss.str();
#endif
      return false;
    }
    
  }
  return true;
}

bool HitPairGeneratorFromLayerPairForPhotonConversion::getPhiRange(float& Phimin, float& Phimax, const DetLayer& layer, const ConversionRegion &convRegion, const edm::EventSetup& es){
   if(layer.location() == GeomDetEnumerators::barrel){
     return getPhiRange(Phimin,Phimax,getLayerRadius(layer),convRegion,es);
   }else if (layer.location() == GeomDetEnumerators::endcap){
     float Z=getLayerZ(layer);
     float R=Z/convRegion.cotTheta();
     return getPhiRange(Phimin,Phimax,R,convRegion,es); //FIXME
   }
   return false;
}

bool HitPairGeneratorFromLayerPairForPhotonConversion::getPhiRange(float& Phimin, float& Phimax, const float& layerR, const ConversionRegion &convRegion, const edm::EventSetup& es){
  Phimin = reco::deltaPhi(convRegion.convPoint().phi(),0.);
  
  float dphi;
  float ptmin=0.1;
  float DeltaL=layerR-convRegion.convPoint().perp();

  if(DeltaL<0){
    Phimin=0;
    Phimax=0;
    return false;
  }

  float theRCurvatureMin = PixelRecoUtilities::bendingRadius(ptmin,es);

  if(theRCurvatureMin<DeltaL)
    dphi = atan(DeltaL/layerR);
  else
    dphi = atan(theRCurvatureMin/layerR * ( 1 - sqrt(1-sqr(DeltaL/theRCurvatureMin)) ) );
  
  if(convRegion.charge()>0){
    Phimax=Phimin;
    Phimin=Phimax-dphi;
  }else{
    Phimax=Phimin+dphi;
  }

  //std::cout << dphi << " " << Phimin << " " << Phimax << " " << layerR << " " << DeltaL  << " " << convRegion.convPoint().phi() << " " << convRegion.convPoint().perp()<< std::endl;
  return true;
}  

bool HitPairGeneratorFromLayerPairForPhotonConversion::
checkRZCompatibilityWithSeedTrack(const RecHitsSortedInPhi::Hit& hit,const DetLayer& layer,const ConversionRegion& convRegion){
  static const float nSigmaRZ = std::sqrt(12.f);
  Range hitCotTheta;
  
  double sigmaCotTheta = convRegion.errTheta() * (1+convRegion.cotTheta()*convRegion.cotTheta()); //Error Propagation from sigma theta.
  Range allowedCotTheta(convRegion.cotTheta()-nSigmaRZ*sigmaCotTheta,convRegion.cotTheta()+nSigmaRZ*sigmaCotTheta);
  
  double dz        = hit->globalPosition().z()-convRegion.pvtxPoint().z();
  double r_reduced = std::sqrt( sqr(hit->globalPosition().x()-convRegion.pvtxPoint().x())+sqr(hit->globalPosition().y()-convRegion.pvtxPoint().y()));

  if (layer.location() == GeomDetEnumerators::barrel){ 
    float zErr = nSigmaRZ * hit->errorGlobalZ();
    hitCotTheta = Range(getCot(dz-zErr,r_reduced),getCot(dz+zErr,r_reduced));
  }else{
    float rErr = nSigmaRZ * hit->errorGlobalR();
    if(dz>0)  
      hitCotTheta = Range(getCot(dz,r_reduced+rErr),getCot(dz,r_reduced-rErr));
    else
      hitCotTheta = Range(getCot(dz,r_reduced-rErr), getCot(dz,r_reduced+rErr));
  }

  Range crossRange = allowedCotTheta.intersection(hitCotTheta);

#ifdef mydebug_Seed      
      ss 
    << "\n\t\t cotTheta allowed Range " << allowedCotTheta.min() << " \t, " << allowedCotTheta.max() 
    << "\n\t\t hitCotTheta   Range " << hitCotTheta.min()   << " \t, " << hitCotTheta.max() 
    << "\n\t\t Cross   Range " << crossRange.min()   << " \t, " << crossRange.max() 
    << "\n\t\t the seed track has origin " << convRegion.convPoint() << " \t cotTheta " << convRegion.cotTheta()  
    << std::endl;
#endif

  return crossRange.empty();
}


double HitPairGeneratorFromLayerPairForPhotonConversion::
getCot(double dz, double dr){
  if ( std::abs(dr) > 1.e-4f )    return dz/dr;
  else
    if(dz>0) return  99999.f; 
    else     return -99999.f; 
}