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 10 of file alpha_T.h.

Member Function Documentation

minimum_deltaSumPT()

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

inlinestatic

Definition at line 27 of file alpha_T.h.

                                                                 {
    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(), [](auto x, auto y) { return fabs(x) < fabs(y); }));
  }

References change_name::diff, mps_fire::i, dqmiolumiharvest::j, x, and y.

Referenced by operator()().

operator()()

template<class LVs >

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

inline

Definition at line 12 of file alpha_T.h.

                                          {
    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_fn(&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());
  }

References minimum_deltaSumPT(), mathSSE::sqrt(), and HcalDetIdTransform::transform().