Represent an event for kinematic fitting as a collection of four-momenta. Each object is represented as an instance of FE_Obj. There may be an object for a neutrino. If that is the case, it is always at the end of the object list. It is not included in the count returned by nobjs(). But is is included in nobjs_all(). More...

#include <Fourvec_Event.h>

Public Member Functions
void	add (const FE_Obj &obj)
	Add an object to the event. The object should not be a neutrino, use the method set_nu_p for that.
	Fourvec_Event ()
	Default constructor.
bool	has_neutrino () const
	Return TRUE is this event contains a neutrino, otherwise returns FALSE.
const Fourvec &	kt () const
	Access the $k_{T}$ four-momentum.
double	kt_x_error () const
	Return the x uncertainty in $k_{T}$ .
double	kt_xy_covar () const
	Return the xy covariance in $k_{T}$ .
double	kt_y_error () const
	Return the y uncertainty in $k_{T}$ .
int	nobjs () const
	Return the number of objects in the event not including any neutrinos.
int	nobjs_all () const
	Return the number of objects in the event including any neutrinos.
const Fourvec &	nu () const
	Access the neutrino four-momentum.
const FE_Obj &	obj (std::vector< FE_Obj >::size_type i) const
	Access object at index i, with the convention that the index starts at 0.
void	set_kt_error (double kt_x_error, double kt_y_error, double kt_xy_covar)
	Set the uncertainties on $k_{T}$ .
void	set_nu_p (const Fourvec &p)
	Set the neutrino four-momentum to . This method adds a neutrino if there wasn't already one.
void	set_obj_p (std::vector< FE_Obj >::size_type i, const Fourvec &p)
	Set the four-momentum of object at index i to .
void	set_x_p (const Fourvec &p)
	Set the four-momentum of the object.
const Fourvec &	x () const
	Access the four-momentum.
Private Attributes
bool	_has_neutrino
Fourvec	_kt
double	_kt_x_error
double	_kt_xy_covar
double	_kt_y_error
std::vector< FE_Obj >	_objs
Fourvec	_x
Friends
std::ostream &	operator<< (std::ostream &s, const Fourvec_Event &fe)
	Output stream operator, print the content of this Fourvec_Event object to an output stream.

Detailed Description

Represent an event for kinematic fitting as a collection of four-momenta. Each object is represented as an instance of FE_Obj. There may be an object for a neutrino. If that is the case, it is always at the end of the object list. It is not included in the count returned by nobjs(). But is is included in nobjs_all().

We can also record the other $x$ momentum, that will be added into the $k_{T}$ sum. This can be used to store a missing transverse energy that is not attributed to a neutrino but is instead due to mismeasurement. Typically this will be set to zero in events that have a neutrino, and to the measured missing transverse energy in events that do not.

Definition at line 202 of file Fourvec_Event.h.

Constructor & Destructor Documentation

hitfit::Fourvec_Event::Fourvec_Event ( )

Default constructor.

Definition at line 112 of file Fourvec_Event.cc.

  : _kt_x_error (0),
    _kt_y_error (0),
    _kt_xy_covar (0),
    _has_neutrino (false)
{
}

Member Function Documentation

void hitfit::Fourvec_Event::add ( const FE_Obj & obj )

Add an object to the event. The object should not be a neutrino, use the method set_nu_p for that.

Parameters:

obj	The FE_Obj to add.

Definition at line 268 of file Fourvec_Event.cc.

References _has_neutrino, _kt, _objs, hitfit::FE_Obj::label, hitfit::nu_label, obj(), and hitfit::FE_Obj::p.

{
  assert (obj.label != nu_label);

  // Add to the end of the list, but before any neutrino.
  if (_has_neutrino) {
    assert (_objs.size() > 0);
    _objs.insert (_objs.begin() + _objs.size() - 1, obj);
  }
  else
    _objs.push_back (obj);

  // Maintain kt.
  _kt += obj.p;
}

bool hitfit::Fourvec_Event::has_neutrino ( ) const

Return TRUE is this event contains a neutrino, otherwise returns FALSE.

Definition at line 124 of file Fourvec_Event.cc.

References _has_neutrino.

Referenced by hitfit::Fourvec_Constrainer::constrain(), and hitfit::Fourvec_Constraint_Calculator::eval().

{
  return _has_neutrino;
}

const Fourvec & hitfit::Fourvec_Event::kt ( ) const

Access the $k_{T}$ four-momentum.

Definition at line 184 of file Fourvec_Event.cc.

References _kt.

{
  return _kt;
}

double hitfit::Fourvec_Event::kt_x_error ( ) const

Return the x uncertainty in $k_{T}$ .

Definition at line 202 of file Fourvec_Event.cc.

References _kt_x_error.

Referenced by set_kt_error().

{
  return _kt_x_error;
}

double hitfit::Fourvec_Event::kt_xy_covar ( ) const

Return the xy covariance in $k_{T}$ .

Definition at line 226 of file Fourvec_Event.cc.

References _kt_xy_covar.

Referenced by set_kt_error().

{
  return _kt_xy_covar;
}

double hitfit::Fourvec_Event::kt_y_error ( ) const

Return the y uncertainty in $k_{T}$ .

Definition at line 214 of file Fourvec_Event.cc.

References _kt_y_error.

Referenced by set_kt_error().

{
  return _kt_y_error;
}

int hitfit::Fourvec_Event::nobjs ( ) const

Return the number of objects in the event not including any neutrinos.

Definition at line 136 of file Fourvec_Event.cc.

References _has_neutrino, and _objs.

Referenced by hitfit::Fourvec_Constrainer::constrain(), and hitfit::Fourvec_Constraint_Calculator::eval().

{
  return _objs.size() - (_has_neutrino ? 1 : 0);
}

int hitfit::Fourvec_Event::nobjs_all ( ) const

Return the number of objects in the event including any neutrinos.

Definition at line 149 of file Fourvec_Event.cc.

References _objs.

Referenced by hitfit::Pair_Table::Pair_Table().

{
  return _objs.size();
}

const Fourvec & hitfit::Fourvec_Event::nu ( ) const

Access the neutrino four-momentum.

Definition at line 174 of file Fourvec_Event.cc.

References _has_neutrino, and _objs.

{
  assert (_has_neutrino);
  return _objs.back().p;
}

const FE_Obj & hitfit::Fourvec_Event::obj ( std::vector< FE_Obj >::size_type i ) const

Access object at index i, with the convention that the index starts at 0.

Parameters:

i	The index of the desired object.

Definition at line 161 of file Fourvec_Event.cc.

References i.

Referenced by add(), and hitfit::Pair_Table::Pair_Table().

{
  assert (i < _objs.size ());
  return _objs[i];
}

void hitfit::Fourvec_Event::set_kt_error	(	double	kt_x_error,
		double	kt_y_error,
		double	kt_xy_covar
	)

Set the uncertainties on $k_{T}$ .

Parameters:

kt_x_error	The uncertainty in the component of $k_{T}$ .
kt_y_error	The uncertainty in the component of $k_{T}$ .
kt_xy_covar	The covariance between the and component of $k_{T}$ .

Definition at line 344 of file Fourvec_Event.cc.

References _kt_x_error, _kt_xy_covar, _kt_y_error, kt_x_error(), kt_xy_covar(), and kt_y_error().

{
  _kt_x_error = kt_x_error;
  _kt_y_error = kt_y_error;
  _kt_xy_covar = kt_xy_covar;
}

void hitfit::Fourvec_Event::set_nu_p ( const Fourvec & p )

Set the neutrino four-momentum to $p$ . This method adds a neutrino if there wasn't already one.

Parameters:

p	The new four-momentum of the neutrino.

Definition at line 292 of file Fourvec_Event.cc.

References _has_neutrino, _kt, _objs, hitfit::nu_label, and AlCaHLTBitMon_ParallelJobs::p.

{
  if (_has_neutrino) {
    _kt -= _objs.back().p;
    _objs.back().p = p;
  }
  else {
    _has_neutrino = true;
    _objs.push_back (FE_Obj (p, 0, nu_label, 0, 0, 0, false));
  }

  _kt += p;
}

void hitfit::Fourvec_Event::set_obj_p	(	std::vector< FE_Obj >::size_type	i,
		const Fourvec &	p
	)

Set the four-momentum of object at index i to $p$ .

Parameters:

i	The position index of the object to change.
p	The new four-momentum of object at index i.

Definition at line 314 of file Fourvec_Event.cc.

References _kt, _objs, i, and AlCaHLTBitMon_ParallelJobs::p.

{
  assert (i < _objs.size ());
  _kt -= _objs[i].p;
  _objs[i].p = p;
  _kt += p;
}

void hitfit::Fourvec_Event::set_x_p ( const Fourvec & p )

Set the four-momentum of the $x$ object.

Parameters:

p	The new four-momentum of the object.

Definition at line 330 of file Fourvec_Event.cc.

References _kt, _x, and AlCaHLTBitMon_ParallelJobs::p.

{
  _kt -= _x;
  _x = p;
  _kt += p;
}

const Fourvec & hitfit::Fourvec_Event::x ( ) const

Access the $x$ four-momentum.

Definition at line 193 of file Fourvec_Event.cc.

References _x.

{
  return _x;
}

Friends And Related Function Documentation

std::ostream& operator<<	(	std::ostream &	s,
		const Fourvec_Event &	fe
	)		`[friend]`

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

Parameters:

s	The stream to which to write.
fe	The instance of Fourvec_Event to be printed.

Definition at line 246 of file Fourvec_Event.cc.

{
  s << "kt: (" << fe._kt.x() << ", " << fe._kt.y() << "); "
    << " error: " << fe._kt_x_error << " " << fe._kt_y_error << " "
    << fe._kt_xy_covar << "\n";
  s << "x: " << fe._x << "\n";
  for (unsigned i = 0; i < fe._objs.size(); i++)
    s << i+1 << ": " << fe._objs[i];
  return s;
}