alpha_T Struct Reference

#include <alpha_T.h>

Public Member Functions
template<class LVs >
double	operator() (const LVs &p4s) const

Static Public Member Functions
static double	minimum_deltaSumPT (const std::vector< double > &pTs)

Detailed Description

Definition at line 11 of file alpha_T.h.

Member Function Documentation

static double alpha_T::minimum_deltaSumPT ( const std::vector< double > &  pTs )

inlinestatic

Definition at line 27 of file alpha_T.h.

References mps_update::diff, i, and j.

Referenced by operator()().

                                                                 {
    std::vector<double> diff( 1<<(pTs.size()-1) , 0. );
    for(unsigned i=0; i < diff.size(); i++)
      for(unsigned j=0; j < pTs.size(); j++)
    diff[i] += pTs[j] * ( 1 - 2 * (int(i>>j)&1) ) ;
    
    return fabs( *min_element( diff.begin(), diff.end(), fabs_less() ) );
  }

template<class LVs >

double alpha_T::operator() ( const LVs &  p4s ) const

inline

Definition at line 14 of file alpha_T.h.

References minimum_deltaSumPT(), reco::tau::disc::Pt(), mathSSE::sqrt(), and create_public_lumi_plots::transform.

                                          {  typedef typename LVs::value_type LorentzV;
    if( p4s.size() < 2 ) return 0;
    
    std::vector<double> pTs;  
    transform( p4s.begin(), p4s.end(), back_inserter(pTs), std::mem_fun_ref(&LorentzV::Pt));
    
    const double DsumPT = minimum_deltaSumPT( pTs );
    const double sumPT = accumulate( pTs.begin(), pTs.end(), double(0) );
    const LorentzV sumP4 = accumulate( p4s.begin(), p4s.end(), LorentzV() );
    
    return 0.5 * ( sumPT - DsumPT ) / sqrt( sumPT*sumPT - sumP4.Perp2() );
  }