hephysics.jet

Class ParticleD

java.lang.Object

hephysics.jet.ParticleD

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable<ParticleD>

public class ParticleD
extends java.lang.Object
implements java.lang.Comparable<ParticleD>, java.io.Serializable

A class representing a jet or particle with pre-computed px,py,pz,e (double precision). It uses double types to keep information on 4-meomenta. The merging is done in the 4-momentum space. The class has a minimum dynamic computation to minimize CPU usage.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ParticleD() Initialize pseudoparticle.
ParticleD(double px, double py, double pz, double energy) Initialize from 4-momenta.

Method Summary

Modifier and Type	Method and Description
void	add(ParticleD a) Add to this particle another particle.
void	add(ParticleD a, int index) Add to this particle another particle.
void	addConstituent(int i)
void	cachePhiRapidity() The method precomputers Phi, Rapidity and Pt2 and store them.
int	compareTo(ParticleD o) Comparator.
ParticleD	copy(ParticleD o) Copy a particle.
double	e() Get energy.
double	et() Compute transverse energy.
double	et2() Compute transverse energy squared.
double	eta() Compute pseudorapidity.
int[]	getConstituents() Get indexes of constituents, iff filled with the "add" method
java.util.List<java.lang.Integer>	getConstituentsList() Get indexes of constituents, iff filled with the "add" method
double	getPhi() Get cached phi
double	getPt() Get cached Pt.
double	getPt2() Get cached perp**2.
double	getRapidity() Get cached rapidity
int	hashCode() Get a hash code
double	m() Compute mass.
double	mag() Compute magnitude sqrt(px**2+py**2+pz**2)
double	mass() Compute mass.
double	perp() Compute transverse momentum (pT).
double	perp2() Compute pT**2.
double	phi() Compute Phi
double	px() Get px.
double	py() Get py.
double	pz() Get pz.
double	rapidity() Compute rapidity.
void	setConstituents(java.util.ArrayList<java.lang.Integer> consts)
void	setEnergy(double energy) Set energy.
void	setPhi(double phi)
void	setPt2(double pt2)
void	setPtEtaPhiM(double pt, double eta, double phi, double m) Set 4-momentum of a particle using transverse momentum (pt), pseudorapidity (eta) and azimuthal angle (phi) and mass (m).
void	setPx(double px)
void	setPxPyPzE(double px, double py, double pz, double energy) Initialize from 4-momenta.
void	setPy(double py)
void	setPz(double pz)
void	setRapidity(double rapidity)
java.lang.String	toString() Convert a particle to a string.

Methods inherited from class java.lang.Object

equals, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

ParticleD

public ParticleD()

Initialize pseudoparticle.

ParticleD

public ParticleD(double px,
                 double py,
                 double pz,
                 double energy)

Initialize from 4-momenta.

Parameters:

px -

py -

pz -

energy -

Method Detail

setPxPyPzE

public void setPxPyPzE(double px,
                       double py,
                       double pz,
                       double energy)

Initialize from 4-momenta.

Parameters:

px -

py -

pz -

energy -

setPtEtaPhiM

public void setPtEtaPhiM(double pt,
                         double eta,
                         double phi,
                         double m)

Set 4-momentum of a particle using transverse momentum (pt), pseudorapidity (eta) and azimuthal angle (phi) and mass (m). In this case, the energy is Math.sqrt(px*px+py*py+pz*pz-m*m).

Parameters:

pt - transverse momentum of a particle.

eta - eta (pseudorapidity) .

phi - azimuthal angle

m - mass

eta

public double eta()

Compute pseudorapidity.

Returns:

pseudorapidity.

et2

public double et2()

Compute transverse energy squared.

Returns:

transverse energy squared.

et

public double et()

Compute transverse energy.

Returns:

transverse energy.

mass

public double mass()

Compute mass.

Returns:

mass

m

public double m()

Compute mass.

Returns:

mass

rapidity

public double rapidity()

Compute rapidity. 0.5*log( (m+z)/(m-z) );

Returns:

rapidity

mag

public double mag()

Compute magnitude sqrt(px**2+py**2+pz**2)

Returns:

mag

perp2

public double perp2()

Compute pT**2.

Returns:

pt**2

perp

public double perp()

Compute transverse momentum (pT).

Returns:

Transverse momentum (pt)

setEnergy

public void setEnergy(double energy)

Set energy.

compareTo

public int compareTo(ParticleD o)

Comparator. Use pT2 for comparison (in increasing order)

Specified by:

compareTo in interface java.lang.Comparable<ParticleD>

Parameters:

o - particle

Returns:

copy

public ParticleD copy(ParticleD o)

Copy a particle.

Parameters:

o -

Returns:

a copy of particle

toString

public java.lang.String toString()

Convert a particle to a string.

Overrides:

toString in class java.lang.Object

Returns:

a string with the particle

px

public double px()

Get px.

Returns:

px component

py

public double py()

Get py.

Returns:

py component

pz

public double pz()

Get pz.

Returns:

pz component

getRapidity

public double getRapidity()

Get cached rapidity

Returns:

rapidity

getPt2

public double getPt2()

Get cached perp**2.

Returns:

perp2.

getPt

public double getPt()

Get cached Pt.

Returns:

et transverse energy

getPhi

public double getPhi()

Get cached phi

Returns:

cached phi

getConstituentsList

public java.util.List<java.lang.Integer> getConstituentsList()

Get indexes of constituents, iff filled with the "add" method

Returns:

list of constituents.

setConstituents

public void setConstituents(java.util.ArrayList<java.lang.Integer> consts)

addConstituent

public void addConstituent(int i)

getConstituents

public int[] getConstituents()

Get indexes of constituents, iff filled with the "add" method

Returns:

array of constituents.

phi

public double phi()

Compute Phi

Returns:

e

public double e()

Get energy.

Returns:

energy component

setPx

public void setPx(double px)

setPy

public void setPy(double py)

setPz

public void setPz(double pz)

setRapidity

public void setRapidity(double rapidity)

setPhi

public void setPhi(double phi)

setPt2

public void setPt2(double pt2)

cachePhiRapidity

public void cachePhiRapidity()

The method precomputers Phi, Rapidity and Pt2 and store them. Such caching makes faster computations. Use getRapidity(), getPhi(), getPt2() methods to return such values.

add

public void add(ParticleD a)

Add to this particle another particle. The method also precomputes rapidity, phi and pt2 for fast retrival using getPhi, getRapidity methods.

Parameters:

a -

add

public void add(ParticleD a,
                int index)

Add to this particle another particle. Also add index of the added particle, which will be stored as an array. The method also precomputes rapidity, phi and et2 for fast retrival using getPhi, getRapidity methods.

Parameters:

a -

index - index of the particle to be stored

hashCode

public int hashCode()

Get a hash code

Overrides:

hashCode in class java.lang.Object