VoronoiMeshMedium Class Reference

#include <VoronoiMeshMedium.hpp>

Inheritance diagram for VoronoiMeshMedium:

Protected Member Functions
	VoronoiMeshMedium ()
Snapshot *	createAndOpenSnapshot () override
VoronoiMeshSnapshot *	voronoiMesh () const override
Protected Member Functions inherited from MeshMedium
	MeshMedium ()
const Box &	domain () const
void	setupSelfBefore () override
Protected Member Functions inherited from ImportedMedium
	ImportedMedium ()
	~ImportedMedium ()
virtual Snapshot *	createAndOpenSnapshot ()=0
void	setupSelfAfter () override
Protected Member Functions inherited from Medium
	Medium ()
Protected Member Functions inherited from SimulationItem
	SimulationItem ()
virtual bool	offersInterface (const std::type_info &interfaceTypeInfo) const
virtual void	setupSelfAfter ()
virtual void	setupSelfBefore ()
Protected Member Functions inherited from Item
	Item ()
Protected Member Functions inherited from SiteListInterface
	SiteListInterface ()
Protected Member Functions inherited from VoronoiMeshInterface
	VoronoiMeshInterface ()

Private Types
using	BaseType = MeshMedium
using	ItemType = VoronoiMeshMedium

Private Attributes
VoronoiMeshSnapshot *	_voronoiMeshSnapshot

Friends
class	ItemRegistry

Additional Inherited Members
Public Types inherited from MeshMedium
enum class	MassType : int {   MassDensity , Mass , MassDensityAndMass , NumberDensity ,   Number , NumberDensityAndNumber }
Public Member Functions inherited from MeshMedium
MassType	massType () const
double	maxX () const
double	maxY () const
double	maxZ () const
double	minX () const
double	minY () const
double	minZ () const
Public Member Functions inherited from ImportedMedium
Vec	bulkVelocity (Position bfr) const override
int	dimension () const override
string	filename () const
Position	generatePosition () const override
bool	hasMagneticField () const override
bool	hasMetallicity () const override
bool	hasParameters () const override
bool	hasTemperature () const override
bool	hasVariableMix () const override
bool	hasVelocity () const override
bool	importMagneticField () const
bool	importMetallicity () const
bool	importTemperature () const
bool	importVariableMixParams () const
bool	importVelocity () const
Vec	magneticField (Position bfr) const override
double	mass () const override
double	massDensity (Position bfr) const override
double	massFraction () const
MaterialMix *	materialMix () const
MaterialMixFamily *	materialMixFamily () const
double	maxTemperature () const
double	metallicity (Position bfr) const override
const MaterialMix *	mix () const override
const MaterialMix *	mix (Position bfr) const override
double	number () const override
double	numberDensity (Position bfr) const override
int	numSites () const override
double	opticalDepthX (double lambda) const override
double	opticalDepthY (double lambda) const override
double	opticalDepthZ (double lambda) const override
void	parameters (Position bfr, Array &params) const override
Position	sitePosition (int index) const override
const Snapshot *	snapshot () const
double	temperature (Position bfr) const override
string	useColumns () const
virtual Vec	bulkVelocity (Position bfr) const =0
virtual int	dimension () const =0
virtual Position	generatePosition () const =0
virtual bool	hasMagneticField () const =0
virtual bool	hasMetallicity () const =0
virtual bool	hasParameters () const =0
virtual bool	hasTemperature () const =0
virtual bool	hasVariableMix () const =0
virtual bool	hasVelocity () const =0
virtual Vec	magneticField (Position bfr) const =0
virtual double	mass () const =0
virtual double	massDensity (Position bfr) const =0
virtual double	metallicity (Position bfr) const =0
virtual const MaterialMix *	mix () const =0
virtual const MaterialMix *	mix (Position bfr) const =0
virtual double	number () const =0
virtual double	numberDensity (Position bfr) const =0
virtual double	opticalDepthX (double lambda) const =0
virtual double	opticalDepthY (double lambda) const =0
virtual double	opticalDepthZ (double lambda) const =0
virtual void	parameters (Position bfr, Array &params) const =0
virtual double	temperature (Position bfr) const =0
Public Member Functions inherited from SimulationItem
template<class T >
T *	find (bool setup=true) const
template<class T >
T *	interface (int levels=-999999, bool setup=true) const
virtual string	itemName () const
void	setup ()
string	typeAndName () const
Public Member Functions inherited from Item
	Item (const Item &)=delete
virtual	~Item ()
void	addChild (Item *child)
const vector< Item * > &	children () const
virtual void	clearItemListProperty (const PropertyDef *property)
void	destroyChild (Item *child)
virtual bool	getBoolProperty (const PropertyDef *property) const
virtual vector< double >	getDoubleListProperty (const PropertyDef *property) const
virtual double	getDoubleProperty (const PropertyDef *property) const
virtual string	getEnumProperty (const PropertyDef *property) const
virtual int	getIntProperty (const PropertyDef *property) const
virtual vector< Item * >	getItemListProperty (const PropertyDef *property) const
virtual Item *	getItemProperty (const PropertyDef *property) const
virtual string	getStringProperty (const PropertyDef *property) const
int	getUtilityProperty (string name) const
virtual void	insertIntoItemListProperty (const PropertyDef *property, int index, Item *item)
Item &	operator= (const Item &)=delete
Item *	parent () const
virtual void	removeFromItemListProperty (const PropertyDef *property, int index)
virtual void	setBoolProperty (const PropertyDef *property, bool value)
virtual void	setDoubleListProperty (const PropertyDef *property, vector< double > value)
virtual void	setDoubleProperty (const PropertyDef *property, double value)
virtual void	setEnumProperty (const PropertyDef *property, string value)
virtual void	setIntProperty (const PropertyDef *property, int value)
virtual void	setItemProperty (const PropertyDef *property, Item *item)
virtual void	setStringProperty (const PropertyDef *property, string value)
void	setUtilityProperty (string name, int value)
virtual string	type () const
Public Member Functions inherited from SiteListInterface
virtual	~SiteListInterface ()
virtual int	numSites () const =0
virtual Position	sitePosition (int index) const =0
Public Member Functions inherited from VoronoiMeshInterface
virtual	~VoronoiMeshInterface ()
virtual VoronoiMeshSnapshot *	voronoiMesh () const =0

Detailed Description

A VoronoiMeshMedium instance represents a transfer medium with a spatial density distribution described by a list of sites generating a Voronoi tesselation of a cubodail domain. The data is usually extracted from a cosmological simulation snapshot, and it must be provided in a column text file formatted as described below.

Refer to the description of the TextInFile class for information on overall formatting and on how to include header lines specifying the units for each column in the input file. In case the input file has no unit specifications, the default units mentioned below are used instead. The number of columns expected in the input file depends on the options configured by the user for this VoronoiMeshMedium instance:

\[ x\,(\mathrm{pc}) \quad y\,(\mathrm{pc}) \quad z\,(\mathrm{pc}) \quad \{\, \rho\,(\text{M}_\odot\,\text{pc}^{-3}) \;\;|\;\; M\,(\text{M}_\odot) \;\;|\;\; n\,(\text{cm}^{-3}) \;\;|\;\; N\,(1) \,\} \quad [Z\,(1)] \quad [T\,(\mathrm{K})] \quad [ v_x\,(\mathrm{km/s}) \quad v_y\,(\mathrm{km/s}) \quad v_z\,(\mathrm{km/s}) ] \quad [ B_x\,(\mu\mathrm{G}) \quad B_y\,(\mu\mathrm{G}) \quad B_z\,(\mu\mathrm{G}) ] \quad [ \dots\text{mix family params}\dots ] \]

The first three columns are the \(x\), \(y\) and \(z\) coordinates of the Voronoi site (i.e. the location defining a particular Voronoi cell).

Depending on the value of the massType option, the fourth column lists the average mass density \(\rho\), the integrated mass \(M\), the average number density \(n\), or the integrated number density \(N\) for the cell corresponding to the site. This quantity is multiplied by the value of the massFraction option.

If the importMetallicity option is enabled, the next column specifies a "metallicity" fraction, which is multiplied with the mass/density column to obtain the actual mass/density of the cell corresponding to the site. If the importTemperature option is enabled, the next column specifies a temperature. If this temperature is higher than the value of the maxTemperature option, the mass and density for the site are set to zero, regardless of the mass or density specified in the fourth column. If the importTemperature option is disabled, or the maximum temperature value is set to zero, such a cutoff is not applied.

If both the importMetallicity and importTemperature options are enabled, this leads to the following expression for the density of an imported site (or a simular formula for the other mass quantity types):

\[ \rho_\mathrm{imported} = \begin{cases} f_\mathrm{mass}\,Z\,\rho & \mathrm{if}\; T<T_\mathrm{max} \;\mathrm{or}\; T_\mathrm{max}=0 \\ 0 & \mathrm{otherwise} \end{cases} \]

If the importVelocity option is enabled, the subsequent three columns specify the \(v_x\), \(v_y\), \(v_z\) velocity components of the site (considered as the bulk velocity for the mass represented by the site).

If the importMagneticField option is enabled, the subsequent three columns specify the \(B_x\), \(B_y\), \(B_z\) magnetic field vector components for the cell.

Finally, if the importVariableMixParams option is enabled, the remaining columns specify the parameters used by the configured material mix family to select a particular material mix for the cell.

Avoiding construction of the Voronoi tessellation

The algorithm used by the VoronoiMeshSnapshot class for constructing Voronoi tessellations sometimes fails (for example, when generating sites are too close to each other). In those cases, it can be desirable to forego the construction of the Voronoi tessellation and instead use a nearest neighbor search for sampling the density distribution. This is possible as long as the full tessellation is not needed for other purposes, such as to perform radiative transfer or to generate random positions drawn from the density distribution. An important use case is when the medium density distribution defined on the Voronoi grid is resampled to an octree grid to perform radiative transfer. However, the octree subdivision algorithm requires the total mass of the medium in addition to the density samples. Without the full Voronoi tessellation, it is impossible to calculate the cell volume that would allow conversion between cell density and mass.

To enable this use case, the massType option can be set to include both mass density and volume-integrated mass (or both number density and volume-integrated number) in the imported data file. Thus, if the massType option is set to one of these choices, the import file must include two columns (mass density \(\rho\) plus integrated mass \(M\), or number density \(n\) plus integrated number density \(N\) ). Furthermore, if the simulation configuration allows it (i.e. the full Voronoi tessellation is not needed for other purposes), the VoronoiMeshSnapshot class will use the information in these two columns to calculate the cell volumes and the total medium mass, and it will forego construction of the Voronoi tessellation.

When an item of this type is used, the names provided by the conditional value expression "VoronoiMeshInterface" are inserted into the name sets used for evaluating Boolean expressions.

Constructor & Destructor Documentation

VoronoiMeshMedium()

VoronoiMeshMedium::VoronoiMeshMedium ( )

inlineprotected

Default constructor for concrete Item subclass VoronoiMeshMedium : "a transfer medium imported from data represented on a Voronoi mesh" .

Member Function Documentation

createAndOpenSnapshot()

Snapshot * VoronoiMeshMedium::createAndOpenSnapshot ( )

overrideprotectedvirtual

This function constructs a new VoronoiMeshSnapshot object, calls its open() function, passes it the domain extent configured by the user, configures it to import a mass or a density column, and finally returns a pointer to the object. Ownership of the Snapshot object is transferred to the caller.

Implements ImportedMedium.

voronoiMesh()

VoronoiMeshSnapshot * VoronoiMeshMedium::voronoiMesh ( ) const

overrideprotectedvirtual

This function implements the VoronoiMeshInterface interface. It returns a pointer to the Voronoi mesh snapshot maintained by this geometry.

Implements VoronoiMeshInterface.

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

• VoronoiMeshMedium.hpp