Snapshot Class Reference

#include <Snapshot.hpp>

Inheritance diagram for Snapshot:

Public Types
enum class	CoordinateSystem { CARTESIAN , CYLINDRICAL , SPHERICAL }

Public Member Functions
	Snapshot ()
virtual	~Snapshot ()
double	age (int m) const
double	bias (int m) const
void	close ()
double	currentMass (int m) const
virtual double	density (int m) const =0
virtual double	density (Position bfr) const =0
virtual Box	extent () const =0
virtual Position	generatePosition () const =0
virtual Position	generatePosition (int m) const =0
virtual void	getEntities (EntityCollection &entities, Position bfr) const =0
virtual void	getEntities (EntityCollection &entities, Position bfr, Direction bfk) const =0
bool	hasAge () const
bool	hasBias () const
bool	hasCurrentMass () const
bool	hasInitialMass () const
bool	hasMagneticField () const
bool	hasMetallicity () const
bool	hasParameters () const
bool	hasTemperature () const
bool	hasVelocity () const
bool	hasVelocityDispersion () const
bool	holdsNumber () const
void	importBias ()
void	importBox ()
void	importCurrentMass ()
void	importMagneticField ()
void	importMass ()
void	importMassDensity ()
void	importMetallicity ()
void	importNumber ()
void	importNumberDensity ()
void	importParameters (const vector< SnapshotParameter > &parameters)
void	importPosition ()
void	importSize ()
void	importTemperature ()
void	importVelocity ()
void	importVelocityDispersion ()
double	initialMass (int m) const
Vec	magneticField (int m) const
Vec	magneticField (Position bfr) const
virtual double	mass () const =0
double	metallicity (int m) const
double	metallicity (Position bfr) const
virtual int	numEntities () const =0
void	open (const SimulationItem *item, string filename, string description)
void	parameters (int m, Array &params) const
void	parameters (Position bfr, Array &params) const
virtual Position	position (int m) const =0
virtual void	readAndClose ()
void	setCoordinateSystem (CoordinateSystem coordinateSystem)
void	setMassDensityPolicy (double multiplier, double maxTemperature, bool useMetallicity)
void	setNeedGetEntities ()
double	SigmaX () const
double	SigmaY () const
double	SigmaZ () const
double	temperature (int m) const
double	temperature (Position bfr) const
void	useColumns (string columns)
Vec	velocity (int m) const
Vec	velocity (Position bfr) const
double	velocityDispersion (int m) const
double	volume () const
virtual double	volume (int m) const =0

Protected Member Functions
int	ageIndex () const
int	biasIndex () const
int	boxIndex () const
void	calculateDensityAndMass (Array &rhov, Array &cumrhov, double &mass)
int	currentMassIndex () const
int	densityIndex () const
bool	hasMassDensityPolicy () const
TextInFile *	infile ()
int	initialMassIndex () const
Log *	log () const
void	logMassStatistics (int numIgnored, double totalOriginalMass, double totalMetallicMass, double totalEffectiveMass)
int	magneticFieldIndex () const
int	massIndex () const
double	maxTemperature () const
int	metallicityIndex () const
double	multiplier () const
bool	needGetEntities () const
int	numParameters () const
int	parametersIndex () const
int	positionIndex () const
virtual const Array &	properties (int m) const =0
Random *	random () const
void	setContext (const SimulationItem *item)
int	sizeIndex () const
int	temperatureIndex () const
Units *	units () const
bool	useMetallicity () const
bool	useTemperatureCutoff () const
int	velocityDispersionIndex () const
int	velocityIndex () const

Private Attributes
int	_ageIndex
int	_biasIndex
int	_boxIndex
CoordinateSystem	_coordinateSystem
int	_currentMassIndex
int	_densityIndex
bool	_hasDensityPolicy
bool	_holdsNumber
TextInFile *	_infile
int	_initialMassIndex
Log *	_log
int	_magneticFieldIndex
int	_massIndex
double	_maxTemperature
int	_metallicityIndex
double	_multiplier
bool	_needGetEntities
int	_nextIndex
int	_numParameters
int	_parametersIndex
int	_positionIndex
Random *	_random
int	_sizeIndex
int	_temperatureIndex
Units *	_units
bool	_useMetallicity
int	_velocityDispersionIndex
int	_velocityIndex

Detailed Description

Snapshot is an abstract base class for representing snapshot data that is imported from a column text file and is used to define the properties of primary sources or transfer media. This base class offers facilities to handle the input options, such as determining which columns are to be imported from the text file, and defines a common interface for all snapshot types, for example to obtain the density at a given position. The actual implementation must be provided in a derived class for each snapshot type.

Some snapshot types use smoothed particles and some use spatial cells as their basic constituents. To avoid mentioning both, we use the generic term entity for referring to either particles or cells.

A Snapshot instance must be initialized using the following strict calling sequence; calling any of the getters before the initialization sequence has completed results in undefined behavior:

• open the input file by calling the open() function
• configure the input file columns by calling the applicable importXXX() functions in the order the columns are expected to appear in the text file;
• configure other options by calling the applicable setXXX() functions;
• read the file calling the readAndClose() function.

The functions for extracting information from a snapshot once it is loaded are thread-safe. However, the functions for configuring options and reading the snapshot file are not thread-safe; they must be called from a single thread (for each snapshot object).

Member Enumeration Documentation

CoordinateSystem

enum class Snapshot::CoordinateSystem

strong

This enum has a constant for each of the supported coordinate systems.

Constructor & Destructor Documentation

Snapshot()

Snapshot::Snapshot

(

)

The default constructor initializes the snapshot in an invalid state; see the description of the required calling sequence in the class header.

~Snapshot()

virtual Snapshot::~Snapshot ( )

virtual

The destructor deletes the input file object, if it would still be present. The fact that the destructor is virtual ensures that derived classes can be propertly destructed through a pointer to this base class.

Member Function Documentation

age()

double Snapshot::age

(

int

m

)

const

This function returns the age of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the age is not being imported, or the index is out of range, the behavior is undefined.

ageIndex()

int Snapshot::ageIndex ( ) const

inlineprotected

This function returns the column index of the age field, or -1 if this is not being imported, for use by subclasses.

bias()

double Snapshot::bias

(

int

m

)

const

This function returns the bias of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the bias is not being imported, or the index is out of range, the behavior is undefined.

biasIndex()

int Snapshot::biasIndex ( ) const

inlineprotected

This function returns the column index of the bias field, or -1 if this is not being imported, for use by subclasses.

boxIndex()

int Snapshot::boxIndex ( ) const

inlineprotected

This function returns the column index of the first box field, or -1 if this is not being imported, for use by subclasses.

calculateDensityAndMass()

void Snapshot::calculateDensityAndMass ( Array &  rhov, Array &  cumrhov, double &  mass  )

protected

This function is provided here for use by subclasses that describe the snapshot through cells (as opposed to particles). It determines the densities and the cumulative mass distribution for all cells and stores the result in the provided array arguments, resizing them and replacing any previous contents. The function also accumulates and stores the total mass, and logs mass statistics by calling logMassStatistics().

The function assumes that the snapshot is fully configured, all properties have been read, and the following functions implemented in the subclass return the proper values: numEntities(), properties(m), volume(m).

close()

void Snapshot::close

(

)

This function closes the file and deletes the corresponding file object.

currentMass()

double Snapshot::currentMass

(

int

m

)

const

This function returns the current mass of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the current mass is not being imported, or the index is out of range, the behavior is undefined.

currentMassIndex()

int Snapshot::currentMassIndex ( ) const

inlineprotected

This function returns the column index of the current mass field, or -1 if this is not being imported, for use by subclasses.

density() [1/2]

virtual double Snapshot::density ( int  m ) const

pure virtual

This function returns the mass or number density for the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the index is out of range, if no density policy has been set, or no mass/density information is being imported, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

density() [2/2]

virtual double Snapshot::density ( Position  bfr ) const

pure virtual

This function returns the mass or number density represented by the snapshot at a given point $\mathbf{r}$. If the point is outside the domain, the function returns zero. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

densityIndex()

int Snapshot::densityIndex ( ) const

inlineprotected

This function returns the column index of the density field, or -1 if this is not being imported, for use by subclasses.

extent()

virtual Box Snapshot::extent ( ) const

pure virtual

This function returns the extent of the complete spatial domain of the snapshot as a box lined up with the coordinate axes.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

generatePosition() [1/2]

virtual Position Snapshot::generatePosition ( ) const

pure virtual

This function returns a random position within the spatial domain of the snapshot, drawn from the mass density distribution represented by the snapshot. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

generatePosition() [2/2]

virtual Position Snapshot::generatePosition ( int  m ) const

pure virtual

This function returns a random position within the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$, drawn from an appropriate probability distribution depending on the snapshot type (e.g. uniform for cells, and some smoothing kernel for particles). If the index is out of range, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

getEntities() [1/2]

virtual void Snapshot::getEntities ( EntityCollection &  entities, Position  bfr  ) const

pure virtual

This function replaces the contents of the specified entity collection by the set of entities that overlap the specified point $\mathbf{r}$, with their corresponding weights. If the point is outside the domain or otherwise does not overlap any entity, the collection will be empty.

For a cell-based snapshot, the function returns the cell containing the given point, if any. The weight is set to 1. For a particle-based snapshot, the function returns all particles with a smoothing kernel that overlaps the given point. The weight of a particle is given by the particle's smoothing kernel value at the given point.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

getEntities() [2/2]

virtual void Snapshot::getEntities ( EntityCollection &  entities, Position  bfr, Direction  bfk  ) const

pure virtual

This function replaces the contents of the specified entity collection by the set of entities that overlap the specified path with starting point $\mathbf{r}$ and direction $\mathbf{k}$, with their corresponding weights. If the path does not overlap any entity, the collection will be empty.

For a cell-based snapshot, the weight of a cell is given by the length of the path segment inside the cell. For a particle-based snapshot, the weight of a particle is given by the effective length seen by the path as it crosses the particle's smoothing kernel.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

hasAge()

bool Snapshot::hasAge ( ) const

inline

This function returns true if the age is being imported, and false otherwise.

hasBias()

bool Snapshot::hasBias ( ) const

inline

This function returns true if the bias is being imported, and false otherwise.

hasCurrentMass()

bool Snapshot::hasCurrentMass ( ) const

inline

This function returns true if the current mass is being imported, and false otherwise.

hasInitialMass()

bool Snapshot::hasInitialMass ( ) const

inline

This function returns true if the initial mass is being imported, and false otherwise.

hasMagneticField()

bool Snapshot::hasMagneticField ( ) const

inline

This function returns true if the magnetic field is being imported, and false otherwise.

hasMassDensityPolicy()

bool Snapshot::hasMassDensityPolicy ( ) const

inlineprotected

This function returns true if the user configured the mass or mass density policy and false otherwise, for use by subclasses.

hasMetallicity()

bool Snapshot::hasMetallicity ( ) const

inline

This function returns true if the metallicity is being imported, and false otherwise.

hasParameters()

bool Snapshot::hasParameters ( ) const

inline

This function returns true if parameters are being imported (i.e. if the number of imported parameters is nonzero), and false otherwise.

hasTemperature()

bool Snapshot::hasTemperature ( ) const

inline

This function returns true if the temperature is being imported, and false otherwise.

hasVelocity()

bool Snapshot::hasVelocity ( ) const

inline

This function returns true if the velocity is being imported, and false otherwise.

hasVelocityDispersion()

bool Snapshot::hasVelocityDispersion ( ) const

inline

This function returns true if the velocity dispersion is being imported, and false otherwise.

holdsNumber()

bool Snapshot::holdsNumber ( ) const

inline

This function returns true if the snapshot holds number (density) values, and false if it holds mass (density) values (or if no mass or density column is being imported).

importBias()

void Snapshot::importBias

(

)

This function configures the snapshot to import a bias for each entity in the snapshot.

importBox()

void Snapshot::importBox

(

)

This function configures the snapshot to import a cuboid lined up with the coordinate axes, defined by six components $(x_{\text{min}},y_{\text{min}},z_{\text{min}},x_{\text{max}},y_{\text{max}},z_{\text{max}})$, $(R_{\text{min}},{\phi }_{\text{min}},z_{\text{min}},R_{\text{max}},{\phi }_{\text{max}},z_{\text{max}})$, or $(r_{\text{min}},{\theta }_{\text{min}},{\phi }_{\text{min}},r_{\text{max}},{\theta }_{\text{max}},{\phi }_{\text{max}})$. The default unit is pc, and deg for the angular components.

importCurrentMass()

void Snapshot::importCurrentMass

(

)

This function configures the snapshot to import the current mass (for use by sources). Not to be confused with the initial mass, which is often requested by single stellar population SED families. The default unit is Msun.

importMagneticField()

void Snapshot::importMagneticField

(

)

This function configures the snapshot to import a magnetic field vector with three components $(B_{\text{x}},B_{\text{y}},B_{\text{z}})$, $(B_{\text{R}},B_{\phi },B_{\text{z}})$ or $(B_{\text{r}},B_{\theta },B_{\phi })$. The default unit is $\mu \mathrm{G}$.

importMass()

void Snapshot::importMass

(

)

This function configures the snapshot to import a mass, i.e. mass density integrated over volume (for use by media). The default unit is Msun. It is allowed to combine the importMassDensity() and importMass() options, supporting special use cases where the volume of the entity cannot be derived otherwise. However, combining the "mass" family functions with the "number" family functions is prohibited and leads to undefined behavior.

importMassDensity()

void Snapshot::importMassDensity

(

)

This function configures the snapshot to import a mass density per unit of volume (for use by media). The default unit is Msun/pc3. It is allowed to combine the importMassDensity() and importMass() options, supporting special use cases where the volume of the entity cannot be derived otherwise. However, combining the "mass" family functions with the "number" family functions is prohibited and leads to undefined behavior.

importMetallicity()

void Snapshot::importMetallicity

(

)

This function configures the snapshot to import a (dimensionless) metallicity fraction.

importNumber()

void Snapshot::importNumber

(

)

This function configures the snapshot to import a number, i.e. number density integrated over volume (for use by media). The default unit is 1. It is allowed to combine the importNumberDensity() and importNumber() options, supporting special use cases where the volume of the entity cannot be derived otherwise. However, combining the "mass" family functions with the "number" family functions is prohibited and leads to undefined behavior.

importNumberDensity()

void Snapshot::importNumberDensity

(

)

This function configures the snapshot to import a number density per unit of volume (for use by media). The default unit is 1/cm3. It is allowed to combine the importNumberDensity() and importNumber() options, supporting special use cases where the volume of the entity cannot be derived otherwise. However, combining the "mass" family functions with the "number" family functions is prohibited and leads to undefined behavior.

importParameters()

void Snapshot::importParameters

(

const vector< SnapshotParameter > &

parameters

)

This function configures the snapshot to import a sequence of parameters as described by the specified list of SnapshotParameter metadata objects.

importPosition()

void Snapshot::importPosition

(

)

This function configures the snapshot to import a spatial position with three components $(x,y,z)$, $(R,\phi ,z)$ or $(r,\theta ,\phi )$. The default unit is pc, and deg for the angular components.

importSize()

void Snapshot::importSize

(

)

This function configures the snapshot to import a spatial radial size. The default unit is pc.

importTemperature()

void Snapshot::importTemperature

(

)

This function configures the snapshot to import a temperature. The default unit is K.

importVelocity()

void Snapshot::importVelocity

(

)

This function configures the snapshot to import a velocity with three components $(v_{\text{x}},v_{\text{y}},v_{\text{z}})$, $(v_{\text{R}},v_{\phi },v_{\text{z}})$ or $(v_{\text{r}},v_{\theta },v_{\phi })$. The default unit is km/s.

importVelocityDispersion()

void Snapshot::importVelocityDispersion

(

)

This function configures the snapshot to import a single velocity dispersion value, specifying a random offset to the bulk velocity with a spherically symmetric Gaussian distribution. The default unit is km/s.

infile()

TextInFile * Snapshot::infile ( )

inlineprotected

This function returns a pointer to the input file object. It is intended for use in subclasses.

initialMass()

double Snapshot::initialMass

(

int

m

)

const

This function returns the initial mass of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the initial mass is not being imported, or the index is out of range, the behavior is undefined.

initialMassIndex()

int Snapshot::initialMassIndex ( ) const

inlineprotected

This function returns the column index of the initial mass field, or -1 if this is not being imported, for use by subclasses.

log()

Log * Snapshot::log ( ) const

inlineprotected

This function returns a pointer to an appropriate log object. It is intended for use in subclasses.

logMassStatistics()

void Snapshot::logMassStatistics ( int  numIgnored, double  totalOriginalMass, double  totalMetallicMass, double  totalEffectiveMass  )

protected

This function issues log messages with statistics on the imported masses. It is provided here for use by subclasses.

magneticField() [1/2]

Vec Snapshot::magneticField

(

int

m

)

const

This function returns the magnetic field vector of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the magnetic field is not being imported, or the index is out of range, the behavior is undefined.

magneticField() [2/2]

Vec Snapshot::magneticField

(

Position

bfr

)

const

This function returns the magnetic field vector at the specified point $\mathbf{r}$. If the point is outside the domain, the function returns a zero magnetic field. If the magnetic field is not being imported, the behavior is undefined.

magneticFieldIndex()

int Snapshot::magneticFieldIndex ( ) const

inlineprotected

This function returns the column index of the first magnetic field field, or -1 if this is not being imported, for use by subclasses.

mass()

virtual double Snapshot::mass ( ) const

pure virtual

This function returns the total mass or number represented by the snapshot, which is equivalent to the mass or number density integrated over the complete spatial domain. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

massIndex()

int Snapshot::massIndex ( ) const

inlineprotected

This function returns the column index of the mass field, or -1 if this is not being imported, for use by subclasses.

maxTemperature()

double Snapshot::maxTemperature ( ) const

inlineprotected

This function returns the maximum temperature configured by the user for an entity to have mass, or zero if the user did not configure the mass or mass density policy, for use by subclasses.

metallicity() [1/2]

double Snapshot::metallicity

(

int

m

)

const

This function returns the metallicity of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the metallicity is not being imported, or the index is out of range, the behavior is undefined.

metallicity() [2/2]

double Snapshot::metallicity

(

Position

bfr

)

const

This function returns the metallicity at the specified point $\mathbf{r}$. If the point is outside the domain, the function returns zero. If the metallicity is not being imported, the behavior is undefined.

metallicityIndex()

int Snapshot::metallicityIndex ( ) const

inlineprotected

This function returns the column index of the metallicity field, or -1 if this is not being imported, for use by subclasses.

multiplier()

double Snapshot::multiplier ( ) const

inlineprotected

This function returns the mass or mass density multiplier configured by the user, or zero if the user did not configure the mass or mass density policy, for use by subclasses.

needGetEntities()

bool Snapshot::needGetEntities ( ) const

inlineprotected

This function returns true if one of the getEntities() functions may be called during the simulation, implying that the snapshot must prebuild the required search data structures. Returns false otherwise. For use by subclasses.

numEntities()

virtual int Snapshot::numEntities ( ) const

pure virtual

This function returns the number of entities $N_{\mathrm{e}\mathrm{n}\mathrm{t}}$ in the snapshot.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

numParameters()

int Snapshot::numParameters ( ) const

inlineprotected

This function returns the number of parameters being imported (which may be zero).

open()

void Snapshot::open	(	const SimulationItem *	item,
		string	filename,
		string	description
	)

This function creates an input file object corresponding to the specified file and opens it for reading; if the file can't be opened, a FatalError is thrown. It must be called before invoking any of the configuration functions(). This function takes several arguments: (1) item specifies a simulation item in the hierarchy of the caller (usually the caller itself) used to retrieve context such as an appropriate logger; (2) filename specifies the name of the file, including filename extension but excluding path and simulation prefix; (3) description describes the contents of the file for use in the log message issued after the file is successfully opened.

parameters() [1/2]

void Snapshot::parameters	(	int	m,
		Array &	params
	)		const

This function stores the parameters of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$ into the given array. If parameters are not being imported, or the index is out of range, the behavior is undefined.

parameters() [2/2]

void Snapshot::parameters	(	Position	bfr,
		Array &	params
	)		const

This function stores the parameters at the specified point $\mathbf{r}$ into the given array. If the point is outside the domain, the function returns the appropriate number of zero parameter values. If parameters are not being imported, the behavior is undefined.

parametersIndex()

int Snapshot::parametersIndex ( ) const

inlineprotected

This function returns the column index of the first field in the parameter list, or -1 if this is not being imported, for use by subclasses.

position()

virtual Position Snapshot::position ( int  m ) const

pure virtual

This function returns a characteristic position for the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. Such a position is always available for all snapshot types, regardless of whether a position is explicitly being imported or not. If the index is out of range, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

positionIndex()

int Snapshot::positionIndex ( ) const

inlineprotected

This function returns the column index of the first position field, or -1 if this is not being imported, for use by subclasses.

properties()

virtual const Array & Snapshot::properties ( int  m ) const

protectedpure virtual

This function returns a reference to an array containing the imported properties (in column order) for the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the index is out of range, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

random()

Random * Snapshot::random ( ) const

inlineprotected

This function returns a pointer to an appropriate random generator. It is intended for use in subclasses.

readAndClose()

virtual void Snapshot::readAndClose ( )

virtual

This function reads the snapshot data from the input file, honoring the options set through the configuration functions, stores the data for later use, and closes the file.

The implementation in this base class simply calls close(). Subclasses must override the function to actually read the data and then call close().

Reimplemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

setContext()

void Snapshot::setContext ( const SimulationItem *  item )

protected

This function retrieves the relevant simulation hierarchy context (such as an appropriate logger) from the specified simulation item (usually the caller itself). It is intended for use in subclasses that support use cases where the open() function is never invoked.

setCoordinateSystem()

void Snapshot::setCoordinateSystem

(

CoordinateSystem

coordinateSystem

)

This function configures the snapshot to use the specified coordinate system when importing Position, Box, Velocity, and MagneticField. The default coordinate system is Cartesian.

After the input file has been read, the contents of the Position and Box properties are fully under control of the subclass. On the other hand, the Velocity and MagneticField properties are handled by query functions in this base class. Therefore, if a coordinate system other than Cartesian has been configured, the subclass must convert these vector components from the input coordinate system to the Cartesian coordinate system.

setMassDensityPolicy()

void Snapshot::setMassDensityPolicy	(	double	multiplier,
		double	maxTemperature,
		bool	useMetallicity
	)

This function sets the policy for calculating the mass or mass density at a given spatial position in the snapshot. If the policy is not set during configuration, or if neither of the importMass() and importDensity() functions was invoked, attempting to obtain mass or mass density values results in undefined behavior.

If the policy is set during configuration, the argument values determine the heuristic for calculating the mass or density for each entity:

• If the maxTemperature argument is positive, and the temperature field is being imported and its value for a given entity is positive as well, and the imported temperature is above the maximum temperature, then the mass or density corresponding to this entity is considered to be zero.
• Otherwise, the intrinsic mass or mass density is obtained from the mass or density fields using a mechanism that depends on the snapshot type and possibly on the configuration. If the useMetallicity argument is true, and the metallicity field is being imported, this intrinsic value is multiplied by the metallicity fraction. Finally, it is multiplied by the value of the multiplier argument to obtain the final result.

setNeedGetEntities()

void Snapshot::setNeedGetEntities

(

)

This function notifies the snapshot that one of the getEntities() functions may be called during the simulation, implying that the snapshot must prebuild the required search data structures.

SigmaX()

double Snapshot::SigmaX

(

)

const

This function returns the X-axis surface density of the density distribution represented by the snapshot, defined as the integration of the density along the entire X-axis,

$${\mathrm{\Sigma }}_X={\int }_{x_{\text{min}}}^{x_{\text{max}}}\rho (x,0,0)\text{d}x.$$

This integral is calculated numerically using 10000 samples along the X-axis. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

SigmaY()

double Snapshot::SigmaY

(

)

const

This function returns the Y-axis surface density of the density distribution represented by the snapshot, defined as the integration of the density along the entire Y-axis,

$${\mathrm{\Sigma }}_Y={\int }_{y_{\text{min}}}^{y_{\text{max}}}\rho (0,y,0)\text{d}y.$$

This integral is calculated numerically using 10000 samples along the Y-axis. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

SigmaZ()

double Snapshot::SigmaZ

(

)

const

This function returns the Z-axis surface density of the density distribution represented by the snapshot, defined as the integration of the density along the entire Z-axis,

$${\mathrm{\Sigma }}_Z={\int }_{z_{\text{min}}}^{z_{\text{max}}}\rho (0,0,z)\text{d}z.$$

This integral is calculated numerically using 10000 samples along the Z-axis. If no density policy has been set or no mass/density information is being imported, the behavior is undefined.

sizeIndex()

int Snapshot::sizeIndex ( ) const

inlineprotected

This function returns the column index of the size field, or -1 if this is not being imported, for use by subclasses.

temperature() [1/2]

double Snapshot::temperature

(

int

m

)

const

This function returns the temperature of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the temperature is not being imported, or the index is out of range, the behavior is undefined.

temperature() [2/2]

double Snapshot::temperature

(

Position

bfr

)

const

This function returns the temperature at the specified point $\mathbf{r}$. If the point is outside the domain, the function returns zero. If the temperature is not being imported, the behavior is undefined.

temperatureIndex()

int Snapshot::temperatureIndex ( ) const

inlineprotected

This function returns the column index of the temperature field, or -1 if this is not being imported, for use by subclasses.

units()

Units * Snapshot::units ( ) const

inlineprotected

This function returns a pointer to an appropriate units object. It is intended for use in subclasses.

useColumns()

void Snapshot::useColumns

(

string

columns

)

This function specifies a mapping (defined by the columns argument) between the "physical" columns in the file being imported (defined by the column information in the file header) and the required "logical" columns (defined by calling the other configuration functions). For information on the syntax and semantics of the columns string contents, refer to the description of the TextInFile::useColumns() function.

This function can be called with a non-empty columns string at most once for each snapshot, and such invocation should occur before the first invocation of any other configuration function. Calling this function with an empty columns string is equivalent to not calling it at all.

useMetallicity()

bool Snapshot::useMetallicity ( ) const

inlineprotected

This function returns true if the user configured the mass or mass density policy with a request to use the metallicity, and the metallicity field is being imported. Returns false otherwise. For use by subclasses.

useTemperatureCutoff()

bool Snapshot::useTemperatureCutoff ( ) const

inlineprotected

This function returns true if the user configured the mass or mass density policy with a nonzero maximum temperature and the temperature field is being imported. Returns false otherwise. For use by subclasses.

velocity() [1/2]

Vec Snapshot::velocity

(

int

m

)

const

This function returns the velocity of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the velocity is not being imported, or the index is out of range, the behavior is undefined.

velocity() [2/2]

Vec Snapshot::velocity

(

Position

bfr

)

const

This function returns the velocity at the specified point $\mathbf{r}$. If the point is outside the domain, the function returns zero velocity. If the velocity is not being imported, the behavior is undefined.

velocityDispersion()

double Snapshot::velocityDispersion

(

int

m

)

const

This function returns the velocity dispersion of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the velocity dispersion is not being imported, or the index is out of range, the behavior is undefined.

velocityDispersionIndex()

int Snapshot::velocityDispersionIndex ( ) const

inlineprotected

This function returns the column index of the velocity dispersion field, or -1 if this is not being imported, for use by subclasses.

velocityIndex()

int Snapshot::velocityIndex ( ) const

inlineprotected

This function returns the column index of the first velocity field, or -1 if this is not being imported, for use by subclasses.

volume() [1/2]

double Snapshot::volume

(

)

const

This function returns the volume of the complete domain of the snapshot, taken to be a box lined up with the coordinate axes.

volume() [2/2]

virtual double Snapshot::volume ( int  m ) const

pure virtual

This function returns the volume of the entity with index $0\le m\le N_{\mathrm{e}\mathrm{n}\mathrm{t}}-1$. If the index is out of range, if no density policy has been set, or no mass/density information is being imported, the behavior is undefined.

Implemented in AdaptiveMeshSnapshot, CellSnapshot, CylindricalCellSnapshot, ParticleSnapshot, SphericalCellSnapshot, and VoronoiMeshSnapshot.

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

• Snapshot.hpp