Container for ingoing and outgoing momentum 4-vectors from a reaction. More...

#include <Event.hh>

Public Member Functions
	Event (const Event &other_event)
	Copy constructor.

	Event (const marley::Particle &a, const marley::Particle &b, const marley::Particle &c, const marley::Particle &d, double Ex, int twoJ, const marley::Parity &P)
	Create a two-two scattering event. More...

	Event (double Ex=0.)
	Create an event with dummy particles.

	Event (Event &&other_event)
	Move constructor.

void	add_final_particle (const marley::Particle &p)
	Add a Particle to the vector of final particles.

void	add_initial_particle (const marley::Particle &p)
	Add a Particle to the vector of initial particles.

void	clear ()
	Deletes all particles from the event and resets the nuclear excitation energy to zero.

marley::Particle &	ejectile ()
	Get a non-const reference to the ejectile.

const marley::Particle &	ejectile () const
	Get a const reference to the ejectile.

double	Ex () const
	Get the excitation energy of the residue just after the initial two-body reaction.

const marley::Particle &	final_particle (size_t idx) const
	Returns a const reference to the final particle with the given index. More...

size_t	final_particle_count () const
	Returns the number of final particles in the Event.

void	from_json (const marley::JSON &json)
	Replace the existing event contents with those read from a JSON representation.

std::vector< marley::Particle * > &	get_final_particles ()
	Get a non-const reference to the vector of final particles.

const std::vector< marley::Particle * > &	get_final_particles () const
	Get a const reference to the vector of final particles.

std::vector< marley::Particle * > &	get_initial_particles ()
	Get a non-const reference to the vector of initial particles.

const std::vector< marley::Particle * > &	get_initial_particles () const
	Get a const reference to the vector of initial particles.

const marley::Particle &	initial_particle (size_t idx) const
	Returns a const reference to the initial particle with the given index. More...

size_t	initial_particle_count () const
	Returns the number of initial particles in the Event.

Event &	operator= (const Event &other_event)
	Copy assignment operator.

Event &	operator= (Event &&other_event)
	Move assignment operator.

marley::Parity	parity () const
	Get the intrinsic parity of the residue just after the initial two-body reaction.

void	print (std::ostream &out) const
	Print this event to a std::ostream. More...

void	print_human_readable (std::ostream &out, int num=-1) const
	Print this event to a std::ostream in an annotated format easily readable by humans. More...

marley::Particle &	projectile ()
	Get a non-const reference to the projectile.

const marley::Particle &	projectile () const
	Get a const reference to the projectile.

void	read (std::istream &in)
	Read in this event from a std::istream. Any previous contents of this event will be deleted. More...

bool	read_hepevt (std::istream &in, double *flux_avg_tot_xsec=nullptr)
	Read in this event from a std::istream, assuming it will appear there in HEPEVT format. Any previous contents of this event will be deleted. More...

marley::Particle &	residue ()
	Get a non-const reference to the residue.

const marley::Particle &	residue () const
	Get a const reference to the residue.

marley::Particle &	target ()
	Get a non-const reference to the target.

const marley::Particle &	target () const
	Get a const reference to the target.

marley::JSON	to_json () const
	Create a JSON representation of this event.

int	twoJ () const
	Get two times the spin of the residue just after the initial two-body reaction.

void	write_hepevt (size_t event_num, double flux_avg_tot_xsec, std::ostream &out) const
	Write a HEPEVT record for this event to a std::ostream. Use the spacetime origin (t = 0 mm/c, x = 0 mm, y = 0 mm, z = 0 mm) as the initial position 4-vector for all particles. More...

Protected Member Functions
void	delete_particles ()
	Deletes all owned Particle objects and clears the vectors of initial and final particles.

void	dump_hepevt_particle (const marley::Particle &p, std::ostream &os, int status, int jmohep1=0, int jmohep2=0) const
	Helper function for write_hepevt() More...

Protected Attributes
double	Ex_
	Excitation energy (MeV) of the residue immediately after the two-two scattering reaction. More...

std::vector< marley::Particle * >	final_particles_
	Vector of pointers to each of the final state particles.

std::vector< marley::Particle * >	initial_particles_
	Vector of pointers to each of the initial state particles.

Parity	parity_
	The parity of the residue immediately after the two-two scattering reaction.

int	twoJ_
	Two times the spin of the residue immediately after the two-two scattering reaction.

Detailed Description

Container for ingoing and outgoing momentum 4-vectors from a reaction.

For a two-two scattering reaction a + b → c + d, this class calls the ingoing particles the projectile (a) and target (b). The outgoing particles are called the ejectile (c) and residue (d). If the residue is a composite particle (e.g., a nucleus), then the class member Ex_ stores its excitation energy just after the two-two reaction occurred. After MARLEY simulates its de-excitation, the residue Particle object will be in its ground state, and the final_particles_ member of this class will include Particle objects representing the de-excitation products.

Note: This class manually manages memory (using the “rule of 5”) for the Particle objects that it owns. A better implementation from a modern C++ perspective would be to use vectors of std::unique_ptr<marley::Particle> objects and let those manage the memory (i.e., use the “rule of zero”). This design choice was made to ensure compatibility with ROOT 5, which cannot generate dictionaries for C++11 classes like std::unique_ptr.

Constructor & Destructor Documentation

◆ Event()

marley::Event::Event	(	const marley::Particle &	a,
		const marley::Particle &	b,
		const marley::Particle &	c,
		const marley::Particle &	d,
		double	Ex,
		int	twoJ,
		const marley::Parity &	P
	)

Create a two-two scattering event.

Parameters

a	the projectile
b	the target
c	the ejectile
d	the residue
Ex	residue excitation energy (MeV) just after the two-two reaction

Member Function Documentation

◆ dump_hepevt_particle()

void marley::Event::dump_hepevt_particle	(	const marley::Particle &	p,
		std::ostream &	os,
		int	status,
		int	jmohep1 = `0`,
		int	jmohep2 = `0`
	)		const

protected

Helper function for write_hepevt()

Parameters

p	Particle to write to the HEPEVT record
os	std::ostream being written to
status	Integer status code to use for this particle in the HEPEVT output
jmohep1	Index of the first mother for this particle (used only for a "MARLEY info" dummy particle at the moment)
jmohep2	Index of the second mother for this particle (used only for a "MARLEY info" dummy particle at the moment)

◆ final_particle()

const marley::Particle & marley::Event::final_particle ( size_t idx ) const

inline

Returns a const reference to the final particle with the given index.

Parameters

[in] idx Index of the desired particle

Exceptions

std::out_of_range if idx is greater than or equal to the size of the vector of final particles

◆ initial_particle()

const marley::Particle & marley::Event::initial_particle ( size_t idx ) const

inline

Returns a const reference to the initial particle with the given index.

Parameters

[in] idx Index of the desired particle

Exceptions

std::out_of_range if idx is greater than or equal to the size of the vector of initial particles

◆ print()

void marley::Event::print ( std::ostream & out ) const

Print this event to a std::ostream.

Parameters

out	The std::ostream to which this event will be written

◆ print_human_readable()

void marley::Event::print_human_readable	(	std::ostream &	out,
		int	num = `-1`
	)		const

Print this event to a std::ostream in an annotated format easily readable by humans.

Parameters

out	The std::ostream to which this event will be written
num	An optional event number that will be printed with the rest of the event. If num is negative, then it will be skipped.

◆ read()

void marley::Event::read ( std::istream & in )

Read in this event from a std::istream. Any previous contents of this event will be deleted.

Parameters

in	The std::istream from which this event will be read

◆ read_hepevt()

bool marley::Event::read_hepevt	(	std::istream &	in,
		double *	flux_avg_tot_xsec = `nullptr`
	)

Read in this event from a std::istream, assuming it will appear there in HEPEVT format. Any previous contents of this event will be deleted.

A marley::Error will be thrown if

There are not exactly two particles in the event with the status code HEPEVT_INITIAL_STATE_STATUS_CODE
There is not exactly one particle with status code HEPEVT_INITIAL_STATE_STATUS_CODE that is an ion (a particle for which marley_utils::is_ion() returns true)
More than one lepton (a particle for which marley_utils::is_lepton() returns true) appears in the event with status code HEPEVT_FINAL_STATE_STATUS_CODE
Zero of the particles with status code HEPEVT_FINAL_STATE_STATUS_CODE are ions
Returns
True if the input stream was in a good state after attempting to read in the full HEPEVT record, or false otherwise. This behavior is designed to enable the return value of this function to be used as a while loop condition when reading in multiple HEPEVT records from an input stream. If the return value is false, the event object contents will have been cleared by this function.

◆ write_hepevt()

void marley::Event::write_hepevt	(	size_t	event_num,
		double	flux_avg_tot_xsec,
		std::ostream &	out
	)		const

Write a HEPEVT record for this event to a std::ostream. Use the spacetime origin (t = 0 mm/c, x = 0 mm, y = 0 mm, z = 0 mm) as the initial position 4-vector for all particles.

Parameters

[in]	flux_avg_tot_xsec	The flux-averaged total reaction cross section (MeV^-2) to include in the output HEPEVT record
[in]	event_num	The event number to use in the output HEPEVT record
[out]	The	std::ostream to which the HEPEVT record will be written

Todo:: Alter marley::Event::write_hepevt() so that the user can specify a vertex position 4-vector to use.

Member Data Documentation

◆ Ex_

double marley::Event::Ex_

protected

Excitation energy (MeV) of the residue immediately after the two-two scattering reaction.

Note: The Ex_ class member is always zero for residues that have no excited states.

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

/Users/gardiner/marley/include/marley/Event.hh
/Users/gardiner/marley/src/Event.cc

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Event()

Member Function Documentation

◆ dump_hepevt_particle()

◆ final_particle()

◆ initial_particle()

◆ print()

◆ print_human_readable()

◆ read()

◆ read_hepevt()

◆ write_hepevt()

Member Data Documentation

◆ Ex_