xAOD::IParticlesLookUpTable< T > Class Template Reference

2D look up table for iParticles More...

#include <IParticlesLookUpTable.h>

Collaboration diagram for xAOD::IParticlesLookUpTable< T >:

Public Member Functions
	IParticlesLookUpTable (unsigned int nbins=50, float minPt=1e-3)
	constructor taking the desired binsize
void	init (const DataVector< T > &particles)
	initialize the look up table with an iParticle container
void	clear ()
	clear the look up table
template<class O>
bool	iParticlesInCone (float eta, float phi, float dr, O &output) const
	collect IParticles in a given cone
bool	isInitialized () const
	return whether table is initialized

Private Member Functions
float	phiInRange (float phi) const
	hepler function to ensure phi is within +-Pi
int	phiIndex (float phi) const
	calculate phi index for a given phi
void	addEntry (int i, std::vector< const T * > &output) const
	add an entry into a vector of pointers
void	addEntry (int i, std::vector< ElementLink< DataVector< T > > > &output) const
	add an entry into a vector of ElementLinks

Private Attributes
const DataVector< T > *	m_container
int	m_nphiBins
float	m_phiBinSize
	number of bins
float	m_minPt
	bin size
std::vector< std::vector< int > >	m_phiBinnedLookUpTable
	cut on minimum Pt for the considered particles

Static Private Attributes
static constexpr float	m_2PI = 2*M_PI
	define 2*Pi

Detailed Description

template<class T>
class xAOD::IParticlesLookUpTable< T >

2D look up table for iParticles

Definition at line 17 of file IParticlesLookUpTable.h.

Constructor & Destructor Documentation

IParticlesLookUpTable()

template<class T>

xAOD::IParticlesLookUpTable< T >::IParticlesLookUpTable ( unsigned int nbins = 50, float minPt = 1e-3 )

inline

constructor taking the desired binsize

Definition at line 20 of file IParticlesLookUpTable.h.

                                                                     :m_container(0), 
      m_nphiBins(nbins), 
      m_phiBinSize(m_2PI/m_nphiBins),
      m_minPt(minPt),
      m_phiBinnedLookUpTable()
      {} 

Member Function Documentation

addEntry() [1/2]

template<class T>

void xAOD::IParticlesLookUpTable< T >::addEntry ( int i, std::vector< const T * > & output ) const

private

add an entry into a vector of pointers

Definition at line 153 of file IParticlesLookUpTable.h.

                                                                                      {
     output.push_back( (*m_container)[i]);
  }

addEntry() [2/2]

template<class T>

void xAOD::IParticlesLookUpTable< T >::addEntry ( int i, std::vector< ElementLink< DataVector< T > > > & output ) const

private

add an entry into a vector of ElementLinks

Definition at line 158 of file IParticlesLookUpTable.h.

                                                                                                         {
    output.push_back( ElementLink<DataVector<T> >(*m_container,i) );
  }

clear()

template<class T>

void xAOD::IParticlesLookUpTable< T >::clear

(

)

clear the look up table

Definition at line 73 of file IParticlesLookUpTable.h.

                                       {
    m_phiBinnedLookUpTable.clear();
  }

init()

template<class T>

void xAOD::IParticlesLookUpTable< T >::init

(

const DataVector< T > &

particles

)

initialize the look up table with an iParticle container

resize hash table

loop over iparticles and copy them into the look-up struct use hashing for phi look-up and sorting for eta look-up

Definition at line 78 of file IParticlesLookUpTable.h.

                                                                      {
    m_phiBinnedLookUpTable.resize(m_nphiBins);
    m_container = &particles;
    unsigned int size = particles.size();
    for( unsigned int i=0; i<size;++i ){
      if(particles[i]->pt()>m_minPt){//sanity check (mainly due to Truth)
    int index = phiIndex(particles[i]->phi());
    m_phiBinnedLookUpTable[index].push_back(i);
      }
    }
    //std::cout << " initializing lookup " << m_container->size() << std::endl;
    for( auto& vec : m_phiBinnedLookUpTable ) {
      if( vec.empty() ) continue;
      std::stable_sort(vec.begin(),vec.end(),[&](int i, int j) { return (*m_container)[i]->eta() < (*m_container)[j]->eta(); });
      // std::cout << " new phi slice " << vec.size() << " eta " ;
      // for( auto index : vec ){
      //   std::cout << "  " << (*m_container)[index]->eta();
      // }
      // std::cout << std::endl;
    }
  }

iParticlesInCone()

template<class T>

template<class O>

bool xAOD::IParticlesLookUpTable< T >::iParticlesInCone	(	float	eta,
		float	phi,
		float	dr,
		O &	output ) const

collect IParticles in a given cone

check if initialized

comparison functions for upper and lower bound

get phi hash ranges

Definition at line 104 of file IParticlesLookUpTable.h.

                                                                                                   {

    if( m_phiBinnedLookUpTable.empty() ) return false;
  
    auto compEta1 = [&](int i,double val ) { return (*m_container)[i]->eta() < val; };
    auto compEta2 = [&](double val,int i ) { return val < (*m_container)[i]->eta(); };

    int indexMin = phiIndex( phiInRange(phi-dr) );
    int indexMax = phiIndex( phiInRange(phi+dr) );
    //std::cout << " eta " << eta << " phi " << phi << " phi ranges " << indexMin << " " << indexMax << std::endl;
    // special treatment for boundary region
    std::vector< std::pair<int,int> > ranges;
    if( indexMin > indexMax ) {
      ranges.push_back( std::make_pair(0,indexMax) );
      ranges.push_back( std::make_pair(indexMin,m_nphiBins-1) );      
    }else{
      ranges.push_back( std::make_pair(indexMin,indexMax) );
    }
    
    float dr2Cut = dr*dr;
 
    // loop over ranges 
    for( auto& range : ranges ){
      indexMin = range.first;
      indexMax = range.second;
      for( ; indexMin <= indexMax; ++indexMin ){
        // get iterators for iparticles to be included 
        const std::vector< int >& tps = m_phiBinnedLookUpTable[indexMin];
        auto it_min = std::lower_bound (tps.begin(),tps.end(),eta-dr,compEta1  );
        auto it_max = std::upper_bound (it_min,tps.end(),eta+dr,compEta2 );
        //std::cout << " new range, entries in bounds " << std::distance(it_max,it_min) << std::endl;
        // add iparticles in cone
        for( ;it_min!=it_max;++it_min ){
          const T* entry = (*m_container)[*it_min];
          float deta = eta- entry->eta();
          float dphi = phiInRange(phi-entry->phi());
          float dr2 = deta*deta + dphi*dphi;
          //std::cout << "   new entry: " << *it_min << " eta,phi " << entry->eta() << " phi " << entry->phi() << " dr " << sqrt(dr2) << std::endl;
          if( dr2 < dr2Cut )  addEntry( *it_min, output );
        }
      }
    }
    return true;
  }

isInitialized()

template<class T>

bool xAOD::IParticlesLookUpTable< T >::isInitialized

(

)

const

return whether table is initialized

Definition at line 69 of file IParticlesLookUpTable.h.

{ return !m_phiBinnedLookUpTable.empty(); }

phiIndex()

template<class T>

int xAOD::IParticlesLookUpTable< T >::phiIndex ( float phi ) const

inlineprivate

calculate phi index for a given phi

Definition at line 52 of file IParticlesLookUpTable.h.

{ return (phi + M_PI)/m_phiBinSize; };

phiInRange()

template<class T>

float xAOD::IParticlesLookUpTable< T >::phiInRange ( float phi ) const

inlineprivate

hepler function to ensure phi is within +-Pi

Definition at line 45 of file IParticlesLookUpTable.h.

                                      { 
      while (phi >= M_PI) phi -= m_2PI;
      while (phi < -M_PI) phi += m_2PI;
      return phi;
    }

Member Data Documentation

m_2PI

template<class T>

float xAOD::IParticlesLookUpTable< T >::m_2PI = 2*M_PI

staticconstexprprivate

define 2*Pi

Definition at line 42 of file IParticlesLookUpTable.h.

m_container

template<class T>

const DataVector<T>* xAOD::IParticlesLookUpTable< T >::m_container

private

Definition at line 61 of file IParticlesLookUpTable.h.

m_minPt

template<class T>

float xAOD::IParticlesLookUpTable< T >::m_minPt

private

bin size

Definition at line 64 of file IParticlesLookUpTable.h.

m_nphiBins

template<class T>

int xAOD::IParticlesLookUpTable< T >::m_nphiBins

private

Definition at line 62 of file IParticlesLookUpTable.h.

m_phiBinnedLookUpTable

template<class T>

std::vector< std::vector< int > > xAOD::IParticlesLookUpTable< T >::m_phiBinnedLookUpTable

private

cut on minimum Pt for the considered particles

Definition at line 65 of file IParticlesLookUpTable.h.

m_phiBinSize

template<class T>

float xAOD::IParticlesLookUpTable< T >::m_phiBinSize

private

number of bins

Definition at line 63 of file IParticlesLookUpTable.h.

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The documentation for this class was generated from the following file:

• IParticlesLookUpTable.h