EtaPhiLUT.h

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
// EtaPhi Look-up table for eflowRecClusters
//     author: Teng Jian Khoo
//     date:   Jun 2020
//
// Inspired by IParticlesLookUpTable from ParticlesInConeTools
// By binning in phi and sorting in eta, extraction of objects in
// a small eta/phi region can be accelerated.
// Useful to reduce the number of distance computations needed
// for e.g. track-cluster matching
 
#ifndef EFLOWREC_ETAPHILOOKUPTABLE_H
#define EFLOWREC_ETAPHILOOKUPTABLE_H
 
#include <vector>
 
#include "xAODCaloEvent/CaloCluster.h"
#include "eflowRec/eflowRecCluster.h"
 
namespace eflowRec {

  class EtaPhiLUT {
  public:
  EtaPhiLUT( unsigned int nbins = 50 );
 
  void fill(eflowRecClusterContainer& clustersin);

  std::vector<eflowRecCluster*> clustersInCone( float eta, float phi, float dr ) const;
 
  private:
 
    unsigned int m_nphiBins;    
    float m_phiBinSize;  
    std::vector< std::vector<eflowRecCluster*> > m_phiBinnedLookUpTable; 
  };
 
}   // end of namespace
 
#endif