hitfit::Vector_Resolution Class Reference

Calculate and represent resolution for a vector of , pseudorapidity , and azimuthal angle . An instance of this class holds three Resolution objects, one each for , , and . In addition, we have a flag to indicate if the momentum resolution is in or . This flag is set by appending [/et] at the end of the string. More...

#include <Vector_Resolution.h>

Public Member Functions
const Resolution &	eta_res () const
	Return a constant reference to the pseudorapidity resolution. More...
double	eta_sigma (const Fourvec &v) const
	Calculate the pseudorapidity resolution of a four-momentum. More...
const Resolution &	p_res () const
	Return a constant reference to the momentum resolution. More...
double	p_sigma (const Fourvec &v) const
	Calculate the momentum resolution of a four-momentum. More...
const Resolution &	phi_res () const
	Return a constant reference to the azimuthal angle resolution. More...
double	phi_sigma (const Fourvec &v) const
	Calculate the azimuthal angle resolution of a four-momentum. More...
void	smear (Fourvec &v, CLHEP::HepRandomEngine &engine, bool do_smear_dir=false) const
	Smear a four-momentum according to the resolutions. More...
bool	use_et () const
	Return the use_et flag. More...
	Vector_Resolution ()
	Constructor, instantiate an instance of Vector_Resolution with infinite precision. More...
	Vector_Resolution (std::string s)
	Constructor, instantiate an instance of Vector_Resolution from a string using format as described in the class description. More...
	Vector_Resolution (const Resolution &p_res, const Resolution &eta_res, const Resolution &phi_res, bool use_et=false)
	Constructor, instantiate an instance of Vector_Resolution from three instances of Resolution objects. More...

Private Member Functions
void	smear_dir (Fourvec &v, CLHEP::HepRandomEngine &engine) const
	Helper function to smear direction. More...

Private Attributes
Resolution	_eta_res
Resolution	_p_res
Resolution	_phi_res
bool	_use_et

Friends
std::ostream &	operator<< (std::ostream &s, const Vector_Resolution &r)
	Output stream operator, print the content of this Vector_Resolution object to an output stream. More...

Detailed Description

Calculate and represent resolution for a vector of , pseudorapidity , and azimuthal angle . An instance of this class holds three Resolution objects, one each for , , and . In addition, we have a flag to indicate if the momentum resolution is in or . This flag is set by appending [/et] at the end of the string.

This class is initialized from a string with format

<p-resolution>/<eta-resolution>/<phi-resolution>[/et]

where the resolution formats are given in the documentation for the Resolution class.

Addendum by Haryo Sumowidagdo: When using the inverse flag, only the inverse flag in p-resolution will be used by the fitter to set that flag which says the error in 'p' is really the error on '1/p'. The inverse flag for in eta-resolution and in phi-resolution are not used by the fitter. As usually the angular resolution is of the form

where can be the magnitude of the momentum ( ) or or transverse momentum ( ), one then can (and should!) use the inverse flag for and resolution.

Definition at line 89 of file Vector_Resolution.h.

Constructor & Destructor Documentation

Vector_Resolution() [1/3]

hitfit::Vector_Resolution::Vector_Resolution

(

)

Constructor, instantiate an instance of Vector_Resolution with infinite precision.

Definition at line 91 of file Vector_Resolution.cc.

      : _p_res("0,0,0"),
        _eta_res("0,0,0"),
        _phi_res("0,0,0"),
        _use_et(false)

  {}

Vector_Resolution() [2/3]

hitfit::Vector_Resolution::Vector_Resolution

(

std::string

s

)

Constructor, instantiate an instance of Vector_Resolution from a string using format as described in the class description.

Parameters

s	String enconding the resolution parameters.

Definition at line 103 of file Vector_Resolution.cc.

      : _p_res(field(s, 0)), _eta_res(field(s, 1)), _phi_res(field(s, 2)), _use_et(field(s, 3) == "et") {}

Vector_Resolution() [3/3]

hitfit::Vector_Resolution::Vector_Resolution	(	const Resolution &	p_res,
		const Resolution &	eta_res,
		const Resolution &	phi_res,
		bool	use_et = false
	)

Constructor, instantiate an instance of Vector_Resolution from three instances of Resolution objects.

Parameters

p_res	The momentum resolution.
eta_res	The pseudorapidity resolution.
phi_res	The azimuthal angle resolution.
use_et	If TRUE then use instead of for momentum resolution.

Definition at line 113 of file Vector_Resolution.cc.

      : _p_res(p_res), _eta_res(eta_res), _phi_res(phi_res), _use_et(use_et) {}

Member Function Documentation

eta_res()

const Resolution & hitfit::Vector_Resolution::eta_res

(

)

const

Return a constant reference to the pseudorapidity resolution.

Definition at line 139 of file Vector_Resolution.cc.

References _eta_res.

  {
    return _eta_res;
  }

eta_sigma()

double hitfit::Vector_Resolution::eta_sigma

(

const Fourvec &

v

)

const

Calculate the pseudorapidity resolution of a four-momentum.

Parameters

v	The four-momentum.

Definition at line 226 of file Vector_Resolution.cc.

References findQualityFiles::v.

Referenced by hitfit::Lepjets_Event_Lep::eta_sigma().

  {
    return find_sigma(v, _eta_res, _use_et);
  }

p_res()

const Resolution & hitfit::Vector_Resolution::p_res

(

)

const

Return a constant reference to the momentum resolution.

Definition at line 128 of file Vector_Resolution.cc.

References _p_res.

  {
    return _p_res;
  }

p_sigma()

double hitfit::Vector_Resolution::p_sigma

(

const Fourvec &

v

)

const

Calculate the momentum resolution of a four-momentum.

Parameters

v	The four-momentum.

Definition at line 204 of file Vector_Resolution.cc.

References findQualityFiles::v.

Referenced by hitfit::Lepjets_Event_Lep::p_sigma().

  {
    double sig = find_sigma(v, _p_res, _use_et);
    if (_use_et) {
      if (_p_res.inverse()) {
        sig *= v.perp() / v.e();
      } else {
        sig *= v.e() / v.perp();
      }
    }
    return sig;
  }

phi_res()

const Resolution & hitfit::Vector_Resolution::phi_res

(

)

const

Return a constant reference to the azimuthal angle resolution.

Definition at line 150 of file Vector_Resolution.cc.

References _phi_res.

  {
    return _phi_res;
  }

phi_sigma()

double hitfit::Vector_Resolution::phi_sigma

(

const Fourvec &

v

)

const

Calculate the azimuthal angle resolution of a four-momentum.

Parameters

v	The four-momentum.

Definition at line 240 of file Vector_Resolution.cc.

References findQualityFiles::v.

Referenced by hitfit::Lepjets_Event_Lep::phi_sigma().

  {
    return find_sigma(v, _phi_res, _use_et);
  }

smear()

void hitfit::Vector_Resolution::smear	(	Fourvec &	v,
		CLHEP::HepRandomEngine &	engine,
		bool	do_smear_dir = false
	)		const

Smear a four-momentum according to the resolutions.

Parameters

v	The four-momentum to smear.
engine	The underlying random number generator.
do_smear_dir	If FALSE, only smear the energy. If TRUE, also smear the direction.

Definition at line 316 of file Vector_Resolution.cc.

References findQualityFiles::v.

Referenced by hitfit::Lepjets_Event_Lep::smear().

  {
    double ee = _use_et ? v.perp() : v.e();  // ??? is perp() correct?
    v *= _p_res.pick(ee, ee, engine) / ee;

    if (do_smear_dir) {
      smear_eta(v, ee, _eta_res, engine);
      smear_phi(v, ee, _phi_res, engine);
    }
  }

smear_dir()

void hitfit::Vector_Resolution::smear_dir ( Fourvec &  v, CLHEP::HepRandomEngine &  engine  ) const

private

Helper function to smear direction.

Parameters

v	The four-momentum to smear.
engine	The underlying random number generator.

use_et()

bool hitfit::Vector_Resolution::use_et

(

)

const

Return the use_et flag.

Definition at line 161 of file Vector_Resolution.cc.

References _use_et.

  {
    return _use_et;
  }

Friends And Related Function Documentation

operator<<

std::ostream& operator<< ( std::ostream &  s, const Vector_Resolution &  r  )

friend

Output stream operator, print the content of this Vector_Resolution object to an output stream.

Parameters

s	The stream to which to write.
r	The instance of Vector_Resolution to be printed.

Definition at line 346 of file Vector_Resolution.cc.

  {
    s << r._p_res << "/ " << r._eta_res << "/ " << r._phi_res;
    if (r._use_et)
      s << "/et";
    s << "\n";
    return s;
  }

Member Data Documentation

_eta_res

Resolution hitfit::Vector_Resolution::_eta_res

private

The pseudorapidity resolution.

Definition at line 201 of file Vector_Resolution.h.

Referenced by eta_res().

_p_res

Resolution hitfit::Vector_Resolution::_p_res

private

The momentum resolution.

Definition at line 196 of file Vector_Resolution.h.

Referenced by p_res().

_phi_res

Resolution hitfit::Vector_Resolution::_phi_res

private

The phi resolution.

Definition at line 206 of file Vector_Resolution.h.

Referenced by phi_res().

_use_et

bool hitfit::Vector_Resolution::_use_et

private

The momentum resolution.

Definition at line 211 of file Vector_Resolution.h.

Referenced by use_et().