Class to contain pseudojets, including minimal information of use to to jet-clustering routines. More...

#include <PseudoJet.hh>

Inheritance diagram for fastjet::PseudoJet:

Public Types
enum	{ X = 0, Y = 1, Z = 2, T = 3, NUM_COORDINATES = 4, SIZE = NUM_COORDINATES }
Public Member Functions
	PseudoJet ()
	PseudoJet (const double px, const double py, const double pz, const double E)
	construct a pseudojet from explicit components
template<class L >
	PseudoJet (const L &some_four_vector)
	constructor from any object that has px,py,pz,E = some_four_vector[0--3],
double	E () const
double	e () const
double	px () const
double	py () const
double	pz () const
double	phi () const
	returns phi (in the range 0..2pi)
double	phi_std () const
	returns phi in the range -pi..pi
double	phi_02pi () const
	returns phi in the range 0..2pi
double	rap () const
	returns the rapidity or some large value when the rapidity is infinite
double	rapidity () const
	the same as rap()
double	pseudorapidity () const
	returns the pseudo-rapidity or some large value when the rapidity is infinite
double	eta () const
double	kt2 () const
	returns the squared transverse momentum
double	perp2 () const
	returns the squared transverse momentum
double	perp () const
	returns the scalar transverse momentum
double	m2 () const
	returns the squared invariant mass // like CLHEP
double	mperp2 () const
	returns the squared transverse mass = kt^2+m^2
double	mperp () const
	returns the transverse mass = sqrt(kt^2+m^2)
double	m () const
	returns the invariant mass (If m2() is negative then -sqrt(-m2()) is returned, as in CLHEP)
double	modp2 () const
	return px^2+py^2+pz^2
double	Et () const
	return the transverse energy
double	Et2 () const
	return the transverse energy squared
double	operator() (int i) const
	returns component i, where X==0, Y==1, Z==2, E==3
double	operator[] (int i) const
	returns component i, where X==0, Y==1, Z==2, E==3
PseudoJet &	boost (const PseudoJet &prest)
	transform this jet (given in the rest frame of prest) into a jet in the lab frame [NOT FULLY TESTED]
PseudoJet &	unboost (const PseudoJet &prest)
	transform this jet (given in lab) into a jet in the rest frame of prest [NOT FULLY TESTED]
int	cluster_hist_index () const
	return the cluster_hist_index, intended to be used by clustering routines.
void	set_cluster_hist_index (const int index)
	set the cluster_hist_index, intended to be used by clustering routines.
int	cluster_sequence_history_index () const
	alternative name for cluster_hist_index() [perhaps more meaningful]
void	set_cluster_sequence_history_index (const int index)
	alternative name for set_cluster_hist_index(...) [perhaps more meaningful]
int	user_index () const
	return the user_index, intended to allow the user to "add" information
void	set_user_index (const int index)
	set the user_index, intended to allow the user to "add" information
std::valarray< double >	four_mom () const
	return a valarray containing the four-momentum (components 0-2 are 3-mom, component 3 is energy).
double	kt_distance (const PseudoJet &other) const
	returns kt distance (R=1) between this jet and another
double	plain_distance (const PseudoJet &other) const
	returns squared cylinder (rap-phi) distance between this jet and another
double	squared_distance (const PseudoJet &other) const
	returns squared cylinder (rap-phi) distance between this jet and another
double	delta_phi_to (const PseudoJet &other) const
	returns other.phi() - this.phi(), constrained to be in range -pi .
double	beam_distance () const
	returns distance between this jet and the beam
void	operator*= (double)
	multiply the jet's momentum by the coefficient
void	operator/= (double)
	divide the jet's momentum by the coefficient
void	operator+= (const PseudoJet &)
	add the other jet's momentum to this jet
void	operator-= (const PseudoJet &)
	subtract the other jet's momentum from this jet
void	reset (double px, double py, double pz, double E)
	reset the 4-momentum according to the supplied components and put the user and history indices back to their default values
void	reset (const PseudoJet &psjet)
	reset the PseudoJet to be equal to psjet (including its indices); NB if the argument is derived from a PseudoJet then the "reset" used will be the templated version (which does not know about indices...)
template<class L >
void	reset (const L &some_four_vector)
	reset the 4-momentum according to the supplied generic 4-vector (accessible via indexing, [0]==px,...[3]==E) and put the user and history indices back to their default values.
template<>
	PseudoJet (const siscone::Cmomentum &four_vector)
	shortcut for converting siscone Cmomentum into PseudoJet
template<>
	PseudoJet (const siscone_spherical::CSphmomentum &four_vector)
	shortcut for converting siscone CSphmomentum into PseudoJet
Private Member Functions
void	_finish_init ()
	calculate phi, rap, kt2 based on the 4-momentum components
void	_reset_indices ()
	set the indices to default values
Private Attributes
double	_px
double	_py
double	_pz
double	_E
double	_phi
double	_rap
double	_kt2
int	_cluster_hist_index
int	_user_index

Detailed Description

Class to contain pseudojets, including minimal information of use to to jet-clustering routines.

Definition at line 52 of file PseudoJet.hh.

Member Enumeration Documentation

anonymous enum

Enumerator:

X
Y
Z
T
NUM_COORDINATES
SIZE

Definition at line 123 of file PseudoJet.hh.

{ X=0, Y=1, Z=2, T=3, NUM_COORDINATES=4, SIZE=NUM_COORDINATES };

Constructor & Destructor Documentation

fastjet::PseudoJet::PseudoJet ( ) [inline]

Definition at line 55 of file PseudoJet.hh.

{};

fastjet::PseudoJet::PseudoJet	(	const double	px,
		const double	py,
		const double	pz,
		const double	E
	)

construct a pseudojet from explicit components

Definition at line 47 of file PseudoJet.cc.

                                                                                      {
  
  _E  = E ;
  _px = px;
  _py = py;
  _pz = pz;

  this->_finish_init();

  // some default values for the history and user indices
  _reset_indices();

}

template<class L >

fastjet::PseudoJet::PseudoJet ( const L & some_four_vector ) [inline]

constructor from any object that has px,py,pz,E = some_four_vector[0--3],

Definition at line 286 of file PseudoJet.hh.

                                                                          {

  _px = some_four_vector[0];
  _py = some_four_vector[1];
  _pz = some_four_vector[2];
  _E  = some_four_vector[3];
  _finish_init();
  // some default values for these two indices
  _reset_indices();
}

template<>

fastjet::PseudoJet::PseudoJet ( const siscone::Cmomentum & four_vector )

shortcut for converting siscone Cmomentum into PseudoJet

Definition at line 19 of file SISConePlugin.cc.

                                                                    {
  (*this) = PseudoJet(four_vector.px,four_vector.py,four_vector.pz,
                      four_vector.E);
}

template<>

fastjet::PseudoJet::PseudoJet ( const siscone_spherical::CSphmomentum & four_vector )

shortcut for converting siscone CSphmomentum into PseudoJet

Definition at line 19 of file SISConeSphericalPlugin.cc.

                                                                                 {
  (*this) = PseudoJet(four_vector.px,four_vector.py,four_vector.pz,
                      four_vector.E);
}

Member Function Documentation

void fastjet::PseudoJet::_finish_init ( ) [private]

calculate phi, rap, kt2 based on the 4-momentum components

do standard end of initialisation

Definition at line 64 of file PseudoJet.cc.

References fastjet::MaxRap, and twopi.

                              {
  _kt2 = this->px()*this->px() + this->py()*this->py();
  if (_kt2 == 0.0) {
    _phi = 0.0; } 
  else {
    _phi = atan2(this->py(),this->px());
  }
  if (_phi < 0.0) {_phi += twopi;}
  if (_phi >= twopi) {_phi -= twopi;} // can happen if phi=-|eps<1e-15|?
  if (this->E() == abs(this->pz()) && _kt2 == 0) {
    // Point has infinite rapidity -- convert that into a very large
    // number, but in such a way that different 0-pt momenta will have
    // different rapidities (so as to lift the degeneracy between
    // them) [this can be relevant at parton-level]
    double MaxRapHere = MaxRap + abs(this->pz());
    if (this->pz() >= 0.0) {_rap = MaxRapHere;} else {_rap = -MaxRapHere;}
  } else {
    // get the rapidity in a way that's modestly insensitive to roundoff
    // error when things pz,E are large (actually the best we can do without
    // explicit knowledge of mass)
    double effective_m2 = max(0.0,m2()); // force non tachyonic mass
    double E_plus_pz    = _E + abs(_pz); // the safer of p+, p-
    // p+/p- = (p+ p-) / (p-)^2 = (kt^2+m^2)/(p-)^2
    _rap = 0.5*log((_kt2 + effective_m2)/(E_plus_pz*E_plus_pz));
    if (_pz > 0) {_rap = - _rap;}
  }

  //if (this->E() != abs(this->pz())) {
  //  _rap = 0.5*log((this->E() + this->pz())/(this->E() - this->pz()));
  //    } else {
  //  // Overlapping points can give problems. Let's lift the degeneracy
  //  // in case of multiple 0-pT points (can be found at parton-level)
  //  double MaxRapHere = MaxRap + abs(this->pz());
  //  if (this->pz() >= 0.0) {_rap = MaxRapHere;} else {_rap = -MaxRapHere;}
  //}
}

void fastjet::PseudoJet::_reset_indices ( ) [inline, private]

set the indices to default values

Definition at line 299 of file PseudoJet.hh.

                                      { 
  set_cluster_hist_index(-1);
  set_user_index(-1);
}

double fastjet::PseudoJet::beam_distance ( ) const [inline]

returns distance between this jet and the beam

Definition at line 177 of file PseudoJet.hh.

{return _kt2;}

PseudoJet & fastjet::PseudoJet::boost ( const PseudoJet & prest )

transform this jet (given in the rest frame of prest) into a jet in the lab frame [NOT FULLY TESTED]

transform this jet (given in lab) into a jet in the rest frame of prest

Definition at line 234 of file PseudoJet.cc.

References E(), m(), px(), py(), and pz().

                                                    {
  
  if (prest.px() == 0.0 && prest.py() == 0.0 && prest.pz() == 0.0) 
    return *this;

  double m = prest.m();
  assert(m != 0);

  double pf4  = (  px()*prest.px() + py()*prest.py()
                 + pz()*prest.pz() + E()*prest.E() )/m;
  double fn   = (pf4 + E()) / (prest.E() + m);
  _px +=  fn*prest.px();
  _py +=  fn*prest.py();
  _pz +=  fn*prest.pz();
  _E = pf4;

  _finish_init(); // we need to recalculate phi,rap,kt2
  return *this;
}

int fastjet::PseudoJet::cluster_hist_index ( ) const [inline]

return the cluster_hist_index, intended to be used by clustering routines.

Definition at line 135 of file PseudoJet.hh.

{return _cluster_hist_index;}

int fastjet::PseudoJet::cluster_sequence_history_index ( ) const [inline]

alternative name for cluster_hist_index() [perhaps more meaningful]

Definition at line 140 of file PseudoJet.hh.

                                                    {
    return cluster_hist_index();}

double fastjet::PseudoJet::delta_phi_to ( const PseudoJet & other ) const

returns other.phi() - this.phi(), constrained to be in range -pi .

returns other.phi() - this.phi(), i.e.

. pi

the phi distance to other, constrained to be in range -pi .. pi

Definition at line 325 of file PseudoJet.cc.

References fastjet::d0::inline_maths::phi(), phi(), fastjet::pi, and twopi.

                                                            {
  double dphi = other.phi() - phi();
  if (dphi >  pi) dphi -= twopi;
  if (dphi < -pi) dphi += twopi;
  return dphi;
}

double fastjet::PseudoJet::e ( ) const [inline]

Definition at line 67 of file PseudoJet.hh.

{return _E;} // like CLHEP

double fastjet::PseudoJet::E ( ) const [inline]

Definition at line 66 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_throw_unless_jets_have_same_perp_or_E(), boost(), fastjet::dot_product(), fastjet::have_same_momentum(), fastjet::JadeBriefJet::init(), fastjet::operator+(), fastjet::operator-(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), fastjet::SISConeSphericalPlugin::run_clustering(), fastjet::SISConePlugin::run_clustering(), fastjet::ATLASConePlugin::run_clustering(), and unboost().

{return _E;}

double fastjet::PseudoJet::Et ( ) const [inline]

return the transverse energy

Definition at line 112 of file PseudoJet.hh.

Referenced by fastjet::CMSIterativeConePlugin::run_clustering().

{return (_kt2==0) ? 0.0 : _E/sqrt(1.0+_pz*_pz/_kt2);}

double fastjet::PseudoJet::Et2 ( ) const [inline]

return the transverse energy squared

Definition at line 114 of file PseudoJet.hh.

{return (_kt2==0) ? 0.0 : _E*_E/(1.0+_pz*_pz/_kt2);}

double fastjet::PseudoJet::eta ( ) const [inline]

Definition at line 92 of file PseudoJet.hh.

Referenced by fastjet::CMSIterativeConePlugin::run_clustering().

{return pseudorapidity();}

valarray< double > fastjet::PseudoJet::four_mom ( ) const

return a valarray containing the four-momentum (components 0-2 are 3-mom, component 3 is energy).

Definition at line 105 of file PseudoJet.cc.

                                           {
  valarray<double> mom(4);
  mom[0] = _px;
  mom[1] = _py;
  mom[2] = _pz;
  mom[3] = _E ;
  return mom;
}

double fastjet::PseudoJet::kt2 ( ) const [inline]

returns the squared transverse momentum

Definition at line 95 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequence::jet_scale_for_algorithm().

{return _kt2;}

double fastjet::PseudoJet::kt_distance ( const PseudoJet & other ) const

returns kt distance (R=1) between this jet and another

Definition at line 302 of file PseudoJet.cc.

References _kt2, _phi, _rap, fastjet::d0::inline_maths::min(), fastjet::pi, and twopi.

                                                           {
  //double distance = min(this->kt2(), other.kt2());
  double distance = min(_kt2, other._kt2);
  double dphi = abs(_phi - other._phi);
  if (dphi > pi) {dphi = twopi - dphi;}
  double drap = _rap - other._rap;
  distance = distance * (dphi*dphi + drap*drap);
  return distance;
}

double fastjet::PseudoJet::m ( ) const [inline]

returns the invariant mass (If m2() is negative then -sqrt(-m2()) is returned, as in CLHEP)

specialization of the "reset" template for case where something is reset to a pseudojet -- it then takes the user and history indices from the psjet

Definition at line 321 of file PseudoJet.hh.

Referenced by boost(), main(), operator<<(), and unboost().

                                 {
  double mm = m2();
  return mm < 0.0 ? -std::sqrt(-mm) : std::sqrt(mm);
}

double fastjet::PseudoJet::m2 ( ) const [inline]

returns the squared invariant mass // like CLHEP

Definition at line 101 of file PseudoJet.hh.

Referenced by main().

{return (_E+_pz)*(_E-_pz)-_kt2;}

double fastjet::PseudoJet::modp2 ( ) const [inline]

return px^2+py^2+pz^2

Definition at line 110 of file PseudoJet.hh.

Referenced by fastjet::JadeBriefJet::init(), and fastjet::EECamBriefJet::init().

{return _kt2+_pz*_pz;}

double fastjet::PseudoJet::mperp ( ) const [inline]

returns the transverse mass = sqrt(kt^2+m^2)

Definition at line 105 of file PseudoJet.hh.

{return sqrt(std::abs(mperp2()));}

double fastjet::PseudoJet::mperp2 ( ) const [inline]

returns the squared transverse mass = kt^2+m^2

Definition at line 103 of file PseudoJet.hh.

{return (_E+_pz)*(_E-_pz);}

double fastjet::PseudoJet::operator() ( int i ) const

returns component i, where X==0, Y==1, Z==2, E==3

Definition at line 117 of file PseudoJet.cc.

                                          {
  switch(i) {
  case X:
    return px();
  case Y:
    return py();
  case Z:
    return pz();
  case T:
    return e();
  default:
    ostringstream err;
    err << "PseudoJet subscripting: bad index (" << i << ")";
    throw Error(err.str());
  }
  return 0.;
}

void fastjet::PseudoJet::operator*= ( double coeff )

multiply the jet's momentum by the coefficient

Definition at line 190 of file PseudoJet.cc.

                                       {
  _px *= coeff;
  _py *= coeff;
  _pz *= coeff;
  _E  *= coeff;
  _kt2*= coeff*coeff;
  // phi and rap are unchanged
}

void fastjet::PseudoJet::operator+= ( const PseudoJet & other_jet )

add the other jet's momentum to this jet

Definition at line 208 of file PseudoJet.cc.

References _E, _px, _py, and _pz.

                                                      {
  _px += other_jet._px;
  _py += other_jet._py;
  _pz += other_jet._pz;
  _E  += other_jet._E ;
  _finish_init(); // we need to recalculate phi,rap,kt2
}

void fastjet::PseudoJet::operator-= ( const PseudoJet & other_jet )

subtract the other jet's momentum from this jet

Definition at line 219 of file PseudoJet.cc.

References _E, _px, _py, and _pz.

                                                      {
  _px -= other_jet._px;
  _py -= other_jet._py;
  _pz -= other_jet._pz;
  _E  -= other_jet._E ;
  _finish_init(); // we need to recalculate phi,rap,kt2
}

void fastjet::PseudoJet::operator/= ( double coeff )

divide the jet's momentum by the coefficient

Definition at line 201 of file PseudoJet.cc.

                                       {
  (*this) *= 1.0/coeff;
}

double fastjet::PseudoJet::operator[] ( int i ) const [inline]

returns component i, where X==0, Y==1, Z==2, E==3

Definition at line 119 of file PseudoJet.hh.

{ return (*this)(i); }; // this too

double fastjet::PseudoJet::perp ( ) const [inline]

returns the scalar transverse momentum

Definition at line 99 of file PseudoJet.hh.

Referenced by operator<<(), print_jet(), fastjet::JetDefinition::DefaultRecombiner::recombine(), fastjet::ClusterSequenceAreaBase::subtracted_jet(), and fastjet::ClusterSequenceAreaBase::subtracted_pt().

{return sqrt(_kt2);}    // like CLHEP

double fastjet::PseudoJet::perp2 ( ) const [inline]

returns the squared transverse momentum

Definition at line 97 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_throw_unless_jets_have_same_perp_or_E(), fastjet::ClusterSequence::has_parents(), fastjet::ClusterSequence::inclusive_jets(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), and fastjet::JetDefinition::DefaultRecombiner::recombine().

{return _kt2;}  // like CLHEP

double fastjet::PseudoJet::phi ( ) const [inline]

returns phi (in the range 0..2pi)

Definition at line 73 of file PseudoJet.hh.

Referenced by fastjet::CircularRange::CircularRange(), delta_phi_to(), fastjet::RangeDefinition::is_in_range(), operator<<(), print_jet(), fastjet::JetDefinition::DefaultRecombiner::recombine(), fastjet::CMSIterativeConePlugin::run_clustering(), and fastjet::RangeDefinition::set_position().

{return phi_02pi();}

double fastjet::PseudoJet::phi_02pi ( ) const [inline]

returns phi in the range 0..2pi

Definition at line 80 of file PseudoJet.hh.

{return _phi;}

double fastjet::PseudoJet::phi_std ( ) const [inline]

returns phi in the range -pi..pi

Definition at line 76 of file PseudoJet.hh.

References fastjet::pi, and twopi.

                                 {
    return _phi > pi ? _phi-twopi : _phi;}

double fastjet::PseudoJet::plain_distance ( const PseudoJet & other ) const

returns squared cylinder (rap-phi) distance between this jet and another

Definition at line 315 of file PseudoJet.cc.

References _phi, _rap, fastjet::pi, and twopi.

Referenced by fastjet::TrackJetPlugin::run_clustering().

                                                              {
  double dphi = abs(_phi - other._phi);
  if (dphi > pi) {dphi = twopi - dphi;}
  double drap = _rap - other._rap;
  return (dphi*dphi + drap*drap);
}

double fastjet::PseudoJet::pseudorapidity ( ) const

returns the pseudo-rapidity or some large value when the rapidity is infinite

Definition at line 137 of file PseudoJet.cc.

References fastjet::MaxRap, and fastjet::pi.

                                       {
  if (px() == 0.0 && py() ==0.0) return MaxRap;
  if (pz() == 0.0) return 0.0;

  double theta = atan(perp()/pz());
  if (theta < 0) theta += pi;
  return -log(tan(theta/2));
}

double fastjet::PseudoJet::px ( ) const [inline]

Definition at line 68 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_throw_unless_jets_have_same_perp_or_E(), boost(), fastjet::dot_product(), fastjet::have_same_momentum(), fastjet::JadeBriefJet::init(), fastjet::EECamBriefJet::init(), fastjet::operator+(), fastjet::operator-(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), fastjet::SISConeSphericalPlugin::run_clustering(), fastjet::SISConePlugin::run_clustering(), fastjet::ATLASConePlugin::run_clustering(), and unboost().

{return _px;}

double fastjet::PseudoJet::py ( ) const [inline]

Definition at line 69 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_throw_unless_jets_have_same_perp_or_E(), boost(), fastjet::dot_product(), fastjet::have_same_momentum(), fastjet::JadeBriefJet::init(), fastjet::EECamBriefJet::init(), fastjet::operator+(), fastjet::operator-(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), fastjet::SISConeSphericalPlugin::run_clustering(), fastjet::SISConePlugin::run_clustering(), fastjet::ATLASConePlugin::run_clustering(), and unboost().

{return _py;}

double fastjet::PseudoJet::pz ( ) const [inline]

Definition at line 70 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_throw_unless_jets_have_same_perp_or_E(), boost(), fastjet::dot_product(), fastjet::have_same_momentum(), fastjet::JadeBriefJet::init(), fastjet::EECamBriefJet::init(), fastjet::operator+(), fastjet::operator-(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), fastjet::SISConeSphericalPlugin::run_clustering(), fastjet::SISConePlugin::run_clustering(), fastjet::ATLASConePlugin::run_clustering(), and unboost().

{return _pz;}

double fastjet::PseudoJet::rap ( ) const [inline]

returns the rapidity or some large value when the rapidity is infinite

Definition at line 84 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequenceActiveArea::_transfer_areas(), fastjet::CircularRange::CircularRange(), fastjet::RangeDefinition::is_in_range(), main(), operator<<(), print_jet(), fastjet::JetDefinition::DefaultRecombiner::recombine(), and fastjet::RangeDefinition::set_position().

{return _rap;}

double fastjet::PseudoJet::rapidity ( ) const [inline]

the same as rap()

Definition at line 87 of file PseudoJet.hh.

{return _rap;} // like CLHEP

template<class L >

void fastjet::PseudoJet::reset ( const L & some_four_vector ) [inline]

reset the 4-momentum according to the supplied generic 4-vector (accessible via indexing, [0]==px,...[3]==E) and put the user and history indices back to their default values.

Definition at line 200 of file PseudoJet.hh.

                                                                   {
    reset(some_four_vector[0], some_four_vector[1],
          some_four_vector[2], some_four_vector[3]);
  }

void fastjet::PseudoJet::reset	(	double	px,
		double	py,
		double	pz,
		double	E
	)		`[inline]`

reset the 4-momentum according to the supplied components and put the user and history indices back to their default values

Definition at line 327 of file PseudoJet.hh.

                                                                      {
  _px = px;
  _py = py;
  _pz = pz;
  _E  = E;
  _finish_init();
  _reset_indices();
}

void fastjet::PseudoJet::reset ( const PseudoJet & psjet ) [inline]

reset the PseudoJet to be equal to psjet (including its indices); NB if the argument is derived from a PseudoJet then the "reset" used will be the templated version (which does not know about indices...)

Definition at line 193 of file PseudoJet.hh.

                                             {
    (*this) = psjet;
  }

void fastjet::PseudoJet::set_cluster_hist_index ( const int index ) [inline]

set the cluster_hist_index, intended to be used by clustering routines.

Definition at line 137 of file PseudoJet.hh.

Referenced by fastjet::ClusterSequence::_do_ij_recombination_step(), fastjet::ClusterSequence::plugin_record_ij_recombination(), and fastjet::ClusterSequenceAreaBase::subtracted_jet().

{_cluster_hist_index = index;}

void fastjet::PseudoJet::set_cluster_sequence_history_index ( const int index ) [inline]

alternative name for set_cluster_hist_index(...) [perhaps more meaningful]

Definition at line 144 of file PseudoJet.hh.

                                                                  {
    set_cluster_hist_index(index);}

void fastjet::PseudoJet::set_user_index ( const int index ) [inline]

set the user_index, intended to allow the user to "add" information

Definition at line 151 of file PseudoJet.hh.

Referenced by main(), fastjet::JetDefinition::DefaultRecombiner::preprocess(), fastjet::JetDefinition::DefaultRecombiner::recombine(), FlavourRecombiner::recombine(), fastjet::SISConeSphericalPlugin::run_clustering(), fastjet::SISConePlugin::run_clustering(), and fastjet::ClusterSequenceAreaBase::subtracted_jet().

{_user_index = index;}

double fastjet::PseudoJet::squared_distance ( const PseudoJet & other ) const [inline]

returns squared cylinder (rap-phi) distance between this jet and another

Definition at line 164 of file PseudoJet.hh.

                                                                {
    return plain_distance(other);}

PseudoJet & fastjet::PseudoJet::unboost ( const PseudoJet & prest )

transform this jet (given in lab) into a jet in the rest frame of prest [NOT FULLY TESTED]

transform this jet (given in the rest frame of prest) into a jet in the lab frame;

Definition at line 261 of file PseudoJet.cc.

References E(), m(), px(), py(), and pz().

                                                      {
  
  if (prest.px() == 0.0 && prest.py() == 0.0 && prest.pz() == 0.0) 
    return *this;

  double m = prest.m();
  assert(m != 0);

  double pf4  = ( -px()*prest.px() - py()*prest.py()
                 - pz()*prest.pz() + E()*prest.E() )/m;
  double fn   = (pf4 + E()) / (prest.E() + m);
  _px -=  fn*prest.px();
  _py -=  fn*prest.py();
  _pz -=  fn*prest.pz();
  _E = pf4;

  _finish_init(); // we need to recalculate phi,rap,kt2
  return *this;
}