AlphaT Class Reference

#include <AlphaT.h>

Public Member Functions
template<class T >
	AlphaT (std::vector< T const *> const &p4, bool setDHtZero=false, bool use_et=true)
template<class T >
	AlphaT (std::vector< T > const &p4, bool setDHtZero=false, bool use_et=true)
double	value (void) const
double	value (std::vector< bool > &jet_sign) const

Private Member Functions
double	value_ (std::vector< bool > *jet_sign) const

Private Attributes
std::vector< double >	et_
std::vector< double >	px_
std::vector< double >	py_
bool	setDHtZero_

Detailed Description

Definition at line 8 of file AlphaT.h.

Constructor & Destructor Documentation

AlphaT() [1/2]

template<class T >

AlphaT::AlphaT	(	std::vector< T const *> const &	p4,
		bool	setDHtZero = false,
		bool	use_et = true
	)

AlphaT() [2/2]

template<class T >

AlphaT::AlphaT	(	std::vector< T > const &	p4,
		bool	setDHtZero = false,
		bool	use_et = true
	)

Definition at line 32 of file AlphaT.h.

References et_, px_, py_, setDHtZero_, and HcalDetIdTransform::transform().

                                                                     {
  std::transform(p4.begin(), p4.end(), back_inserter(et_), std::mem_fn(use_et ? &T::Et : &T::Pt));
  std::transform(p4.begin(), p4.end(), back_inserter(px_), std::mem_fn(&T::Px));
  std::transform(p4.begin(), p4.end(), back_inserter(py_), std::mem_fn(&T::Py));
  setDHtZero_ = setDHtZero;
}

Member Function Documentation

value() [1/2]

double AlphaT::value ( void  ) const

inline

Definition at line 40 of file AlphaT.h.

References value_().

Referenced by SUSY_HLT_alphaT::analyze(), and average.Average::average().

{ return value_(nullptr); }

value() [2/2]

double AlphaT::value ( std::vector< bool > &  jet_sign ) const

inline

Definition at line 43 of file AlphaT.h.

References value_().

Referenced by average.Average::average().

{ return value_(&jet_sign); }

value_()

double AlphaT::value_ ( std::vector< bool > *  jet_sign ) const

private

Definition at line 5 of file AlphaT.cc.

References funct::abs(), et_, mps_fire::i, createfilelist::int, dqmiolumiharvest::j, SiStripPI::max, px_, py_, setDHtZero_, mathSSE::sqrt(), and mitigatedMETSequence_cff::U.

Referenced by value().

                                                     {
  // Clear pseudo-jet container
  if (jet_sign) {
    jet_sign->clear();
    jet_sign->resize(et_.size());
  }

  // check the size of the input collection
  if (et_.empty())
    // empty jet collection, return AlphaT = 0
    return 0.;

  if (et_.size() > (unsigned int)std::numeric_limits<unsigned int>::digits)
    // too many jets, return AlphaT = a very large number
    return std::numeric_limits<double>::max();

  // Momentum sums in transverse plane
  const double sum_et = std::accumulate(et_.begin(), et_.end(), 0.);
  const double sum_px = std::accumulate(px_.begin(), px_.end(), 0.);
  const double sum_py = std::accumulate(py_.begin(), py_.end(), 0.);

  // Minimum Delta Et for two pseudo-jets
  double min_delta_sum_et = sum_et;

  if (setDHtZero_) {
    min_delta_sum_et = 0.;
  } else {
    for (unsigned int i = 0; i < (1U << (et_.size() - 1)); i++) {  //@@ iterate through different combinations
      double delta_sum_et = 0.;
      for (unsigned int j = 0; j < et_.size(); ++j) {  //@@ iterate through jets
        if (i & (1U << j))
          delta_sum_et -= et_[j];
        else
          delta_sum_et += et_[j];
      }
      delta_sum_et = std::abs(delta_sum_et);
      if (delta_sum_et < min_delta_sum_et) {
        min_delta_sum_et = delta_sum_et;
        if (jet_sign) {
          for (unsigned int j = 0; j < et_.size(); ++j)
            (*jet_sign)[j] = ((i & (1U << j)) == 0);
        }
      }
    }
  }
  // Alpha_T
  return (0.5 * (sum_et - min_delta_sum_et) / std::sqrt(sum_et * sum_et - (sum_px * sum_px + sum_py * sum_py)));
}

Member Data Documentation

et_

std::vector<double> AlphaT::et_

private

Definition at line 17 of file AlphaT.h.

Referenced by AlphaT(), and value_().

px_

std::vector<double> AlphaT::px_

private

Definition at line 18 of file AlphaT.h.

Referenced by AlphaT(), and value_().

py_

std::vector<double> AlphaT::py_

private

Definition at line 19 of file AlphaT.h.

Referenced by AlphaT(), and value_().

setDHtZero_

bool AlphaT::setDHtZero_

private

Definition at line 27 of file AlphaT.h.

Referenced by AlphaT(), and value_().