#include <nBodyPhaseSpaceGen.h>

Classes
class	rndGen

Public Types
enum	kinematicsTypeEnum { BLOCK = 1, RAUBOLD_LYNCH = 2 }
enum	weightTypeEnum { S_U_CHUNG = 1, NUPHAZ = 2, GENBOD = 3, FLAT = 4, IMPORTANCE = 5 }

Public Member Functions
	nBodyPhaseSpaceGen ()
virtual	~nBodyPhaseSpaceGen ()
bool	setDecay (const std::vector< double > &daughterMasses)
	sets decay constants and prepares internal variables
bool	setDecay (const unsigned int nmbOfDaughters, const double *daughterMasses)
void	setSeed (const unsigned int seed)
	sets seed of random number generator
unsigned int	seed ()
	returns seed of random number generator
double	random ()
	returns number from internal random generator; intended for higher-level generators
void	setProposalBW (double mass, double width)
	set proposal function for importance sampling in the (n-1) isobar mass as simple Breit-Wigner-Shape (to be used with IMPORTANCE weighting option)
double	generateDecay (const TLorentzVector &nBody)
	generates full event with certain n-body mass and momentum and returns event weight
bool	generateDecayAccepted (const TLorentzVector &nBody, const double maxWeight=0)
	generates full event with certain n-body mass and momentum only when event is accepted (return value = true) this function is more efficient, if only weighted events are needed
void	pickMasses (const double nBodyMass)
	randomly choses the (n - 2) effective masses of the respective (i + 1)-body systems
double	calcWeight ()
	computes event weight and breakup momenta operates on vector of intermediate two-body masses prepared by pickMasses()
void	pickAngles ()
	randomly choses the (n - 1) polar and (n - 1) azimuthal angles in the respective (i + 1)-body RFs
void	calcEventKinematics (const TLorentzVector &nBody)
	calculates full event kinematics from the effective masses of the (i + 1)-body systems and the Lorentz vector of the decaying system uses the break-up momenta calculated by calcWeight() and angles from pickAngles()
void	setKinematicsType (const kinematicsTypeEnum kinematicsType)
	selects algorithm used to calculate event kinematics
kinematicsTypeEnum	kinematicsType () const
	returns algorithm used to calculate event kinematics
void	setVerbose (bool flag)
void	setWeightType (const weightTypeEnum weightType)
	selects formula used for weight calculation
weightTypeEnum	weightType () const
	returns formula used for weight calculation
void	setMaxWeight (const double maxWeight)
	sets maximum weight used for hit-miss MC
double	maxWeight () const
	returns maximum weight used for hit-miss MC
double	normalization () const
	returns normalization used in weight calculation
double	eventWeight () const
	returns weight of generated event
double	maxWeightObserved () const
	returns maximum observed weight since instantiation
void	resetMaxWeightObserved ()
	sets maximum observed weight back to zero
double	estimateMaxWeight (const double nBodyMass, const unsigned int nmbOfIterations=10000)
	estimates maximum weight for given n-body mass
bool	eventAccepted (const double maxWeight=0)
	applies event weight in form of hit-miss MC assumes that event weight has been already calculated by calcWeight() if maxWeight > 0 value is used as maximum weight, otherwise _maxWeight value is used
const TLorentzVector &	daughter (const int index) const
	returns Lorentz vector of daughter at index
const std::vector < TLorentzVector > &	daughters () const
	returns Lorentz vectors of all daughters
unsigned int	nmbOfDaughters () const
	returns number of daughters
double	daughterMass (const int index) const
	returns invariant mass of daughter at index
double	intermediateMass (const int index) const
	returns intermediate mass of (index + 1)-body system
double	breakupMom (const int index) const
	returns breakup momentum in (index + 1)-body RF
double	cosTheta (const int index) const
	returns polar angle in (index + 1)-body RF
double	phi (const int index) const
	returns azimuth in (index + 1)-body RF
double	impWeight () const
std::ostream &	print (std::ostream &out=std::cout) const
	prints generator status

Static Private Member Functions
static double	F (const double x, const double y)
	reduced 2-body phase-space factor = 2 * q / M needed for NUPHAS weight calculation

Private Attributes
std::vector< double >	_m
	masses of daughter particles
unsigned int	_n
	number of daughter particles
std::vector< double >	_M
	effective masses of (i + 1)-body systems
std::vector< double >	_cosTheta
	cosine of polar angle of the 2-body decay of the (i + 1)-body system
std::vector< double >	_phi
	azimuthal angle of the 2-body decay of the (i + 1)-body system
std::vector< double >	_mSum
	sums of daughter particle masses
std::vector< double >	_breakupMom
	breakup momenta for the two-body decays: (i + 1)-body –> daughter_(i + 1) + i-body
std::vector< TLorentzVector >	_daughters
	Lorentz vectors of the daughter particles.
weightTypeEnum	_weightType
	switches between different weight formulas
double	_norm
	normalization value
double	_weight
	phase space weight of generated event
double	_impweight
	importance sampling weight
double	_maxWeightObserved
	maximum event weight calculated processing the input data
double	_maxWeight
	maximum weight used to weight events in hit-miss MC
kinematicsTypeEnum	_kinematicsType
	switches between different ways of calculating event kinematics
bool	_verbose
double	_isoBWMass
	Breit-Wigner mass for importance sampling proposal.
double	_isoBWWidth
	Breit-Wigner width for importance sampling proposal.
rndGen	_rnd
	random number generator instance

Friends
std::ostream &	operator<< (std::ostream &out, const nBodyPhaseSpaceGen &gen)

Detailed Description

Definition at line 108 of file nBodyPhaseSpaceGen.h.

Member Enumeration Documentation

enum rpwa::nBodyPhaseSpaceGen::kinematicsTypeEnum

Enumerator:

BLOCK
RAUBOLD_LYNCH

Definition at line 154 of file nBodyPhaseSpaceGen.h.

enum rpwa::nBodyPhaseSpaceGen::weightTypeEnum

Enumerator:

S_U_CHUNG
NUPHAZ
GENBOD
FLAT
IMPORTANCE

Definition at line 164 of file nBodyPhaseSpaceGen.h.

Constructor & Destructor Documentation

nBodyPhaseSpaceGen::nBodyPhaseSpaceGen ( )

Definition at line 103 of file nBodyPhaseSpaceGen.cc.

nBodyPhaseSpaceGen::~nBodyPhaseSpaceGen ( )

virtual

Definition at line 120 of file nBodyPhaseSpaceGen.cc.

Member Function Documentation

double rpwa::nBodyPhaseSpaceGen::breakupMom ( const int index ) const

inline

returns breakup momentum in (index + 1)-body RF

Definition at line 197 of file nBodyPhaseSpaceGen.h.

References _breakupMom.

void nBodyPhaseSpaceGen::calcEventKinematics ( const TLorentzVector & nBody )

calculates full event kinematics from the effective masses of the (i + 1)-body systems and the Lorentz vector of the decaying system uses the break-up momenta calculated by calcWeight() and angles from pickAngles()

Definition at line 414 of file nBodyPhaseSpaceGen.cc.

References _breakupMom, _cosTheta, _daughters, _kinematicsType, _m, _M, _n, _phi, BLOCK, daughter(), i, and RAUBOLD_LYNCH.

Referenced by rpwa::diffractivePhaseSpace::event(), generateDecay(), and generateDecayAccepted().

double nBodyPhaseSpaceGen::calcWeight ( )

computes event weight and breakup momenta operates on vector of intermediate two-body masses prepared by pickMasses()

!! warning: produces distorted angular distribution

Definition at line 357 of file nBodyPhaseSpaceGen.cc.

References _breakupMom, _impweight, _m, _M, _maxWeightObserved, _mSum, _n, _norm, _weight, _weightType, F(), FLAT, GENBOD, i, IMPORTANCE, M2, NUPHAZ, and S_U_CHUNG.

Referenced by estimateMaxWeight(), rpwa::diffractivePhaseSpace::event(), generateDecay(), and generateDecayAccepted().

double rpwa::nBodyPhaseSpaceGen::cosTheta ( const int index ) const

inline

returns polar angle in (index + 1)-body RF

Definition at line 198 of file nBodyPhaseSpaceGen.h.

References _cosTheta.

const TLorentzVector& rpwa::nBodyPhaseSpaceGen::daughter ( const int index ) const

inline

returns Lorentz vector of daughter at index

Definition at line 192 of file nBodyPhaseSpaceGen.h.

References _daughters.

Referenced by calcEventKinematics(), compareAmplitudes(), rpwa::diffractivePhaseSpace::GetDecay(), testNBodyPhaseSpaceGen(), rpwa::diffractivePhaseSpace::writeComGeantAscii(), and rpwa::diffractivePhaseSpace::writePwa2000Ascii().

double rpwa::nBodyPhaseSpaceGen::daughterMass ( const int index ) const

inline

returns invariant mass of daughter at index

Definition at line 195 of file nBodyPhaseSpaceGen.h.

References _m.

const std::vector<TLorentzVector>& rpwa::nBodyPhaseSpaceGen::daughters ( ) const

inline

returns Lorentz vectors of all daughters

Definition at line 193 of file nBodyPhaseSpaceGen.h.

References _daughters.

double nBodyPhaseSpaceGen::estimateMaxWeight	(	const double	nBodyMass,
		const unsigned int	nmbOfIterations = `10000`
	)

estimates maximum weight for given n-body mass

Definition at line 497 of file nBodyPhaseSpaceGen.cc.

References _weight, calcWeight(), i, maxWeight(), and pickMasses().

Referenced by rpwa::diffractivePhaseSpace::BuildDaughterList(), compareAmplitudes(), and testNBodyPhaseSpaceGen().

bool rpwa::nBodyPhaseSpaceGen::eventAccepted ( const double maxWeight = 0 )

inline

applies event weight in form of hit-miss MC assumes that event weight has been already calculated by calcWeight() if maxWeight > 0 value is used as maximum weight, otherwise _maxWeight value is used

Definition at line 285 of file nBodyPhaseSpaceGen.h.

Referenced by generateDecayAccepted().

double rpwa::nBodyPhaseSpaceGen::eventWeight ( ) const

inline

returns weight of generated event

Definition at line 177 of file nBodyPhaseSpaceGen.h.

References _weight.

double rpwa::nBodyPhaseSpaceGen::F	(	const double	x,
		const double	y
	)

inlinestaticprivate

reduced 2-body phase-space factor = 2 * q / M needed for NUPHAS weight calculation

Definition at line 302 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), and pickMasses().

double nBodyPhaseSpaceGen::generateDecay ( const TLorentzVector & nBody )

generates full event with certain n-body mass and momentum and returns event weight

Definition at line 198 of file nBodyPhaseSpaceGen.cc.

References _mSum, _n, _weight, calcEventKinematics(), calcWeight(), pickAngles(), pickMasses(), and print().

Referenced by testNBodyPhaseSpaceGen().

bool nBodyPhaseSpaceGen::generateDecayAccepted	(	const TLorentzVector &	nBody,
		const double	maxWeight = `0`
	)

generates full event with certain n-body mass and momentum only when event is accepted (return value = true) this function is more efficient, if only weighted events are needed

Definition at line 225 of file nBodyPhaseSpaceGen.cc.

References _mSum, _n, calcEventKinematics(), calcWeight(), eventAccepted(), pickAngles(), and pickMasses().

Referenced by compareAmplitudes(), and testNBodyPhaseSpaceGen().

double rpwa::nBodyPhaseSpaceGen::impWeight ( ) const

inline

Definition at line 203 of file nBodyPhaseSpaceGen.h.

References _impweight.

Referenced by rpwa::diffractivePhaseSpace::impWeight().

double rpwa::nBodyPhaseSpaceGen::intermediateMass ( const int index ) const

inline

returns intermediate mass of (index + 1)-body system

Definition at line 196 of file nBodyPhaseSpaceGen.h.

References _M.

kinematicsTypeEnum rpwa::nBodyPhaseSpaceGen::kinematicsType ( ) const

inline

returns algorithm used to calculate event kinematics

Definition at line 157 of file nBodyPhaseSpaceGen.h.

References _kinematicsType.

Referenced by setKinematicsType().

double rpwa::nBodyPhaseSpaceGen::maxWeight ( ) const

inline

returns maximum weight used for hit-miss MC

Definition at line 175 of file nBodyPhaseSpaceGen.h.

References _maxWeight.

Referenced by rpwa::diffractivePhaseSpace::BuildDaughterList(), estimateMaxWeight(), rpwa::diffractivePhaseSpace::event(), and setMaxWeight().

double rpwa::nBodyPhaseSpaceGen::maxWeightObserved ( ) const

inline

returns maximum observed weight since instantiation

Definition at line 178 of file nBodyPhaseSpaceGen.h.

References _maxWeightObserved.

unsigned int rpwa::nBodyPhaseSpaceGen::nmbOfDaughters ( ) const

inline

returns number of daughters

Definition at line 194 of file nBodyPhaseSpaceGen.h.

References _n.

Referenced by setDecay().

double rpwa::nBodyPhaseSpaceGen::normalization ( ) const

inline

returns normalization used in weight calculation

Definition at line 176 of file nBodyPhaseSpaceGen.h.

References _norm.

double rpwa::nBodyPhaseSpaceGen::phi ( const int index ) const

inline

returns azimuth in (index + 1)-body RF

Definition at line 199 of file nBodyPhaseSpaceGen.h.

References _phi.

void rpwa::nBodyPhaseSpaceGen::pickAngles ( )

inline

randomly choses the (n - 1) polar and (n - 1) azimuthal angles in the respective (i + 1)-body RFs

Definition at line 274 of file nBodyPhaseSpaceGen.h.

References _cosTheta, _n, _phi, i, and random().

Referenced by rpwa::diffractivePhaseSpace::event(), generateDecay(), and generateDecayAccepted().

void nBodyPhaseSpaceGen::pickMasses ( const double nBodyMass )

randomly choses the (n - 2) effective masses of the respective (i + 1)-body systems

Definition at line 249 of file nBodyPhaseSpaceGen.cc.

References _impweight, _isoBWMass, _isoBWWidth, _m, _M, _mSum, _n, _weight, _weightType, F(), i, IMPORTANCE, NUPHAZ, and random().

Referenced by estimateMaxWeight(), rpwa::diffractivePhaseSpace::event(), generateDecay(), and generateDecayAccepted().

ostream & nBodyPhaseSpaceGen::print ( std::ostream & out = std::cout ) const

prints generator status

Definition at line 513 of file nBodyPhaseSpaceGen.cc.

References _daughters, _kinematicsType, _maxWeight, _maxWeightObserved, _n, _norm, _weight, _weightType, and i.

Referenced by generateDecay().

double rpwa::nBodyPhaseSpaceGen::random ( )

inline

returns number from internal random generator; intended for higher-level generators

Definition at line 124 of file nBodyPhaseSpaceGen.h.

References _rnd, and rpwa::nBodyPhaseSpaceGen::rndGen::pick().

Referenced by rpwa::diffractivePhaseSpace::event(), pickAngles(), and pickMasses().

void rpwa::nBodyPhaseSpaceGen::resetMaxWeightObserved ( )

inline

sets maximum observed weight back to zero

Definition at line 179 of file nBodyPhaseSpaceGen.h.

References _maxWeightObserved.

Referenced by setDecay().

unsigned int rpwa::nBodyPhaseSpaceGen::seed ( )

inline

returns seed of random number generator

Definition at line 123 of file nBodyPhaseSpaceGen.h.

References _rnd, and rpwa::nBodyPhaseSpaceGen::rndGen::seed().

bool nBodyPhaseSpaceGen::setDecay ( const std::vector< double > & daughterMasses )

sets decay constants and prepares internal variables

Definition at line 126 of file nBodyPhaseSpaceGen.cc.

References _breakupMom, _cosTheta, _daughters, _m, _M, _mSum, _n, _norm, _phi, _weightType, daughterMasses, fact(), FLAT, GENBOD, i, IMPORTANCE, NUPHAZ, resetMaxWeightObserved(), and S_U_CHUNG.

Referenced by rpwa::diffractivePhaseSpace::BuildDaughterList(), compareAmplitudes(), setDecay(), and testNBodyPhaseSpaceGen().

bool nBodyPhaseSpaceGen::setDecay	(	const unsigned int	nmbOfDaughters,
		const double *	daughterMasses
	)

Definition at line 184 of file nBodyPhaseSpaceGen.cc.

References i, nmbOfDaughters(), and setDecay().

void rpwa::nBodyPhaseSpaceGen::setKinematicsType ( const kinematicsTypeEnum kinematicsType )

inline

selects algorithm used to calculate event kinematics

Definition at line 156 of file nBodyPhaseSpaceGen.h.

References _kinematicsType, and kinematicsType().

Referenced by compareAmplitudes(), rpwa::diffractivePhaseSpace::diffractivePhaseSpace(), and testNBodyPhaseSpaceGen().

void rpwa::nBodyPhaseSpaceGen::setMaxWeight ( const double maxWeight )

inline

sets maximum weight used for hit-miss MC

Definition at line 174 of file nBodyPhaseSpaceGen.h.

References _maxWeight, and maxWeight().

Referenced by rpwa::diffractivePhaseSpace::BuildDaughterList(), compareAmplitudes(), and testNBodyPhaseSpaceGen().

void rpwa::nBodyPhaseSpaceGen::setProposalBW	(	double	mass,
		double	width
	)

inline

set proposal function for importance sampling in the (n-1) isobar mass as simple Breit-Wigner-Shape (to be used with IMPORTANCE weighting option)

Definition at line 127 of file nBodyPhaseSpaceGen.h.

References _isoBWMass, _isoBWWidth, and mass.

Referenced by rpwa::diffractivePhaseSpace::SetImportanceBW().

void rpwa::nBodyPhaseSpaceGen::setSeed ( const unsigned int seed )

inline

sets seed of random number generator

Definition at line 122 of file nBodyPhaseSpaceGen.h.

References _rnd, and rpwa::nBodyPhaseSpaceGen::rndGen::setSeed().

Referenced by compareAmplitudes(), rpwa::diffractivePhaseSpace::SetSeed(), and testNBodyPhaseSpaceGen().

void rpwa::nBodyPhaseSpaceGen::setVerbose ( bool flag )

inline

Definition at line 160 of file nBodyPhaseSpaceGen.h.

References _verbose.

Referenced by rpwa::diffractivePhaseSpace::setVerbose().

void rpwa::nBodyPhaseSpaceGen::setWeightType ( const weightTypeEnum weightType )

inline

selects formula used for weight calculation

Definition at line 169 of file nBodyPhaseSpaceGen.h.

References _weightType, and weightType().

Referenced by compareAmplitudes(), rpwa::diffractivePhaseSpace::diffractivePhaseSpace(), rpwa::diffractivePhaseSpace::SetImportanceBW(), and testNBodyPhaseSpaceGen().

weightTypeEnum rpwa::nBodyPhaseSpaceGen::weightType ( ) const

inline

returns formula used for weight calculation

Definition at line 171 of file nBodyPhaseSpaceGen.h.

References _weightType.

Referenced by setWeightType().

Friends And Related Function Documentation

std::ostream& operator<<	(	std::ostream &	out,
		const nBodyPhaseSpaceGen &	gen
	)

friend

Definition at line 205 of file nBodyPhaseSpaceGen.h.

Member Data Documentation

std::vector<double> rpwa::nBodyPhaseSpaceGen::_breakupMom

private

breakup momenta for the two-body decays: (i + 1)-body –> daughter_(i + 1) + i-body

Definition at line 225 of file nBodyPhaseSpaceGen.h.

Referenced by breakupMom(), calcEventKinematics(), calcWeight(), and setDecay().

std::vector<double> rpwa::nBodyPhaseSpaceGen::_cosTheta

private

cosine of polar angle of the 2-body decay of the (i + 1)-body system

Definition at line 222 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), cosTheta(), pickAngles(), and setDecay().

std::vector<TLorentzVector> rpwa::nBodyPhaseSpaceGen::_daughters

private

Lorentz vectors of the daughter particles.

Definition at line 226 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), daughter(), daughters(), print(), and setDecay().

double rpwa::nBodyPhaseSpaceGen::_impweight

private

importance sampling weight

Definition at line 230 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), impWeight(), and pickMasses().

double rpwa::nBodyPhaseSpaceGen::_isoBWMass

private

Breit-Wigner mass for importance sampling proposal.

Definition at line 239 of file nBodyPhaseSpaceGen.h.

Referenced by pickMasses(), and setProposalBW().

double rpwa::nBodyPhaseSpaceGen::_isoBWWidth

private

Breit-Wigner width for importance sampling proposal.

Definition at line 240 of file nBodyPhaseSpaceGen.h.

Referenced by pickMasses(), and setProposalBW().

kinematicsTypeEnum rpwa::nBodyPhaseSpaceGen::_kinematicsType

private

switches between different ways of calculating event kinematics

Definition at line 233 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), kinematicsType(), print(), and setKinematicsType().

std::vector<double> rpwa::nBodyPhaseSpaceGen::_m

private

masses of daughter particles

Definition at line 216 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), calcWeight(), daughterMass(), pickMasses(), and setDecay().

std::vector<double> rpwa::nBodyPhaseSpaceGen::_M

private

effective masses of (i + 1)-body systems

Definition at line 221 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), calcWeight(), intermediateMass(), pickMasses(), and setDecay().

double rpwa::nBodyPhaseSpaceGen::_maxWeight

private

maximum weight used to weight events in hit-miss MC

Definition at line 232 of file nBodyPhaseSpaceGen.h.

Referenced by maxWeight(), print(), and setMaxWeight().

double rpwa::nBodyPhaseSpaceGen::_maxWeightObserved

private

maximum event weight calculated processing the input data

Definition at line 231 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), maxWeightObserved(), print(), and resetMaxWeightObserved().

std::vector<double> rpwa::nBodyPhaseSpaceGen::_mSum

private

sums of daughter particle masses

Definition at line 224 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), generateDecay(), generateDecayAccepted(), pickMasses(), and setDecay().

unsigned int rpwa::nBodyPhaseSpaceGen::_n

private

number of daughter particles

Definition at line 220 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), calcWeight(), generateDecay(), generateDecayAccepted(), nmbOfDaughters(), pickAngles(), pickMasses(), print(), and setDecay().

double rpwa::nBodyPhaseSpaceGen::_norm

private

normalization value

Definition at line 228 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), normalization(), print(), and setDecay().

std::vector<double> rpwa::nBodyPhaseSpaceGen::_phi

private

azimuthal angle of the 2-body decay of the (i + 1)-body system

Definition at line 223 of file nBodyPhaseSpaceGen.h.

Referenced by calcEventKinematics(), phi(), pickAngles(), and setDecay().

rndGen rpwa::nBodyPhaseSpaceGen::_rnd

private

random number generator instance

Definition at line 263 of file nBodyPhaseSpaceGen.h.

Referenced by random(), seed(), and setSeed().

bool rpwa::nBodyPhaseSpaceGen::_verbose

private

Definition at line 237 of file nBodyPhaseSpaceGen.h.

Referenced by setVerbose().

double rpwa::nBodyPhaseSpaceGen::_weight

private

phase space weight of generated event

Definition at line 229 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), estimateMaxWeight(), eventWeight(), generateDecay(), pickMasses(), and print().

weightTypeEnum rpwa::nBodyPhaseSpaceGen::_weightType

private

switches between different weight formulas

Definition at line 227 of file nBodyPhaseSpaceGen.h.

Referenced by calcWeight(), pickMasses(), print(), setDecay(), setWeightType(), and weightType().

The documentation for this class was generated from the following files:

Classes

Public Types

Public Member Functions

Static Private Member Functions

Private Attributes

Friends

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation