Gparticle Class Reference

Lightweight particle specification and primary vertex shooter. More...

#include <gparticle.h>

Public Member Functions
	Gparticle (const std::string &name, int multiplicity, double p, double delta_p, const std::string &punit, const std::string &randomMomentumModel, double theta, double delta_theta, const std::string &thetaModel, double phi, double delta_phi, const std::string &aunit, double avx, double avy, double avz, double adelta_vx, double adelta_vy, double adelta_vz, const std::string &vunit, const std::string &randomVertexModel, const std::shared_ptr< GLogger > &logger, int generator_type=1)
	Constructs a particle configuration from user-facing parameters.
	Gparticle (const Gparticle &)=delete
	Copying is disabled.
Gparticle &	operator= (const Gparticle &)=delete
	Copy assignment is disabled.
	~Gparticle ()
	Destructor emits a debug-level lifecycle message.
void	shootParticle (G4ParticleGun *particleGun, G4Event *anEvent)
	Shoots this particle configuration into a Geant4 event.
const std::string &	getName () const
	Returns the particle name stored in this generator definition.
int	getPid () const
	Returns the resolved PDG particle id.
int	getMultiplicity () const
	Returns how many copies are generated per event.
double	getMomentum () const
	Returns the nominal momentum magnitude.
double	getTheta () const
	Returns the nominal polar angle.
double	getPhi () const
	Returns the nominal azimuthal angle.
const G4ThreeVector &	getVertex () const
	Returns the nominal vertex position.
int	getGeneratorType () const
	Returns the generator source type.
const std::vector< GparticleRuntimeRecord > &	getRuntimeRecords () const
	Returns the runtime records from the most recent shoot.

Static Public Member Functions
static std::shared_ptr< Gparticle >	create_default_gparticle (const std::shared_ptr< GLogger > &log)
	Creates a minimal default particle configuration.

Friends
std::ostream &	operator<< (std::ostream &os, const Gparticle &gp)
	Stream insertion operator used for pretty-printing configuration summaries.
std::ostream &	operator<< (std::ostream &os, const std::shared_ptr< Gparticle > &ptr)
	Stream insertion operator overload for shared pointers.

Detailed Description

A Gparticle instance represents a generator-level particle configuration that can be used to produce primary vertices in a G4Event through a G4ParticleGun.

The class stores:

• Identity: particle name and resolved PDG id
• Multiplicity: number of copies shot per event
• Kinematics: momentum magnitude and angular parameters
• Vertex: position and optional spread/randomization
• Randomization models: selection of uniform/gaussian/cosine (angles) and sphere (vertex)

Configuration is typically created by option parsing utilities and then used during event generation by calling shootParticle().

Logging:

• A logger is provided at construction and retained for diagnostics.
• Verbosity 2 typically prints a full configuration summary via the stream operator.

Definition at line 88 of file gparticle.h.

Constructor & Destructor Documentation

Gparticle() [1/2]

Gparticle::Gparticle	(	const std::string &	name,
		int	multiplicity,
		double	p,
		double	delta_p,
		const std::string &	punit,
		const std::string &	randomMomentumModel,
		double	theta,
		double	delta_theta,
		const std::string &	thetaModel,
		double	phi,
		double	delta_phi,
		const std::string &	aunit,
		double	avx,
		double	avy,
		double	avz,
		double	adelta_vx,
		double	adelta_vy,
		double	adelta_vz,
		const std::string &	vunit,
		const std::string &	randomVertexModel,
		const std::shared_ptr< GLogger > &	logger,
		int	generator_type = 1 )

This constructor converts user-facing numeric values paired with unit strings into internal numeric values (in the unit system returned by gutilities helpers), and converts randomization model strings into gutilities::randomModel values.

The particle PDG id is resolved at construction time by consulting the G4ParticleTable using the provided particle name.

Parameters

name	Particle name as understood by G4ParticleTable (e.g. "e-").
multiplicity	Number of particles to shoot per event.
p	Nominal momentum magnitude (interpreted together with punit).
delta_p	Spread parameter for momentum randomization (interpreted with punit).
punit	Unit string used to interpret p and delta_p (e.g. "MeV", "GeV").
randomMomentumModel	Random model name for momentum (e.g. "uniform", "gaussian").
theta	Nominal polar angle (interpreted together with aunit).
delta_theta	Spread parameter for theta (interpreted with aunit).
thetaModel	Random model name for theta (e.g. "uniform", "cosine", "gaussian").
phi	Nominal azimuthal angle (interpreted together with aunit).
delta_phi	Spread parameter for phi (interpreted with aunit).
aunit	Unit string used to interpret angles (typically "deg" or "rad").
avx	Nominal vertex x component (interpreted together with vunit).
avy	Nominal vertex y component (interpreted together with vunit).
avz	Nominal vertex z component (interpreted together with vunit).
adelta_vx	Spread parameter for vertex x (interpreted with vunit).
adelta_vy	Spread parameter for vertex y (interpreted with vunit).
adelta_vz	Spread parameter for vertex z (interpreted with vunit).
vunit	Unit string used to interpret vertex components (e.g. "cm", "mm").
randomVertexModel	Random model name for vertex (e.g. "uniform", "gaussian", "sphere").
logger	Logger used for diagnostics and error reporting.
generator_type	Generator source type associated with this particle. Inline -gparticle definitions use the default value 1. File-backed particles preserve the source-file type field when the format provides one, such as the Lund type column.

Definition at line 22 of file gparticle.cc.

Gparticle() [2/2]

Gparticle::Gparticle ( const Gparticle & )

delete

The class is intended to be managed through std::shared_ptr and not copied.

~Gparticle()

Gparticle::~Gparticle ( )

inline

Definition at line 165 of file gparticle.h.

Member Function Documentation

create_default_gparticle()

static std::shared_ptr< Gparticle > Gparticle::create_default_gparticle ( const std::shared_ptr< GLogger > & log )

inlinestatic

This helper returns an electron with:

• momentum 1 GeV, no spread
• angles 0 deg, no spread
• vertex at (0,0,0) cm, no spread
• uniform random models where relevant

Parameters

log	Logger to associate with the constructed particle.

Returns

A shared pointer to the default Gparticle configuration.

Definition at line 199 of file gparticle.h.

getGeneratorType()

int Gparticle::getGeneratorType ( ) const

inline

For inline -gparticle entries this is normally 1. For file-backed entries this preserves the source format's type field; in Lund files, type 1 is the subset propagated to Geant4 and included in the generated_tracked output bank.

Returns

Generator source type.

Definition at line 284 of file gparticle.h.

getMomentum()

double Gparticle::getMomentum ( ) const

inline

Returns

Momentum after unit conversion to GEMC internal units.

Definition at line 251 of file gparticle.h.

getMultiplicity()

int Gparticle::getMultiplicity ( ) const

inline

Returns

Configured particle multiplicity.

Definition at line 244 of file gparticle.h.

getName()

const std::string & Gparticle::getName ( ) const

inline

Returns

Particle name used for Geant4 lookup and generated-particle output.

Definition at line 230 of file gparticle.h.

getPhi()

double Gparticle::getPhi ( ) const

inline

Returns

Phi after unit conversion to GEMC internal angular units.

Definition at line 265 of file gparticle.h.

getPid()

int Gparticle::getPid ( ) const

inline

Returns

PDG id resolved from G4ParticleTable during construction.

Definition at line 237 of file gparticle.h.

getRuntimeRecords()

const std::vector< GparticleRuntimeRecord > & Gparticle::getRuntimeRecords ( ) const

inline

One record is stored for each generated primary, so a particle with multiplicity N contributes N runtime records.

Definition at line 292 of file gparticle.h.

getTheta()

double Gparticle::getTheta ( ) const

inline

Returns

Theta after unit conversion to GEMC internal angular units.

Definition at line 258 of file gparticle.h.

getVertex()

const G4ThreeVector & Gparticle::getVertex ( ) const

inline

Returns

Vertex after unit conversion to GEMC internal length units.

Definition at line 272 of file gparticle.h.

operator=()

Gparticle & Gparticle::operator= ( const Gparticle & )

delete

shootParticle()

void Gparticle::shootParticle	(	G4ParticleGun *	particleGun,
		G4Event *	anEvent )

The method resolves the particle definition from the G4ParticleTable (using the stored particle name) and then, for each copy defined by the configured multiplicity:

• sets the particle kinetic energy based on randomized momentum and mass
• sets the momentum direction based on randomized theta/phi
• sets the vertex position based on the configured vertex model
• calls GeneratePrimaryVertex on the provided G4ParticleGun

Error handling:

• If the G4ParticleTable is unavailable, an error is logged.
• If the particle is not found, an error is logged.

Parameters

particleGun	The G4ParticleGun used to generate the primary vertices.
anEvent	The G4Event that receives the generated primary vertices.

Definition at line 77 of file gparticle.cc.

Friends And Related Symbol Documentation

operator<< [1/2]

std::ostream & operator<< ( std::ostream & os, const Gparticle & gp )

friend

Definition at line 247 of file gparticle.cc.

operator<< [2/2]

std::ostream & operator<< ( std::ostream & os, const std::shared_ptr< Gparticle > & ptr )

friend

Parameters

os	Output stream.
ptr	Pointer to a Gparticle; prints "<null Gparticle>" if null.

Returns

Output stream.

Definition at line 361 of file gparticle.h.

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

• gparticle.h
• gparticle.cc