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GaussianGeometry Class Reference

#include <GaussianGeometry.hpp>

Inheritance diagram for GaussianGeometry:
Inheritance graph
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Public Member Functions

double density (double r) const override
 
double dispersion () const
 
double randomRadius () const override
 
double Sigmar () const override
 
- Public Member Functions inherited from SpheGeometry
virtual double density (double r) const =0
 
double density (Position bfr) const override
 
int dimension () const override
 
Position generatePosition () const override
 
virtual double randomRadius () const =0
 
virtual double Sigmar () const =0
 
double SigmaX () const override
 
double SigmaY () const override
 
double SigmaZ () const override
 
virtual double density (Position bfr) const =0
 
virtual int dimension () const =0
 
virtual Position generatePosition () const =0
 
virtual double SigmaX () const =0
 
virtual double SigmaY () const =0
 
virtual double SigmaZ () 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 ItemgetItemProperty (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)
 
Itemoperator= (const Item &)=delete
 
Itemparent () 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
 

Protected Member Functions

 GaussianGeometry ()
 
void setupSelfBefore () override
 
- Protected Member Functions inherited from SpheGeometry
 SpheGeometry ()
 
- Protected Member Functions inherited from Geometry
 Geometry ()
 
Randomrandom () const
 
void setupSelfBefore () override
 
- 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 ()
 

Private Types

using BaseType = SpheGeometry
 
using ItemType = GaussianGeometry
 

Private Attributes

double _dispersion
 
double _rho0
 
Array _rv
 
const double & _sigma
 
Array _Xv
 

Friends

class ItemRegistry
 

Detailed Description

The GaussianGeometry class is a subclass of the SpheGeometry class, and describes spherical geometries characterized by a Gaussian density profile,

\[ \rho(r) = \rho_0\,\exp\left( -\frac{r^2}{2\sigma^2} \right) .\]

This geometry has one parameter, the radial dispersion \(\sigma\).

Constructor & Destructor Documentation

◆ GaussianGeometry()

GaussianGeometry::GaussianGeometry ( )
inlineprotected

Default constructor for concrete Item subclass GaussianGeometry : "a Gaussian geometry" .

Member Function Documentation

◆ density()

double GaussianGeometry::density ( double  r) const
overridevirtual

This function returns the density \(\rho(r)\) at the radius \(r\). It just implements the analytical formula.

Implements SpheGeometry.

◆ dispersion()

GaussianGeometry::dispersion ( ) const
inline

This function returns the value of the discoverable double property dispersion : "the scale length (dispersion) σ" .

This property represents a physical quantity of type "length" .

The minimum value for this property is "]0" .

◆ randomRadius()

double GaussianGeometry::randomRadius ( ) const
overridevirtual

This function returns the radius \(r\) of a random position drawn from a spherical Gaussian density distribution. Such a value can be generated by picking a uniform deviate \({\cal{X}}\) and solving the equation

\[ {\cal{X}} = 4\pi \int_0^r \rho(r')\, r'^2\, {\text{d}}r' \]

for \(r\), where \(\rho(r)\) is the Gaussian radial density profile. This is done by interpolating from the precalculated table of the cumulative distribution.

Implements SpheGeometry.

◆ setupSelfBefore()

void GaussianGeometry::setupSelfBefore ( )
overrideprotectedvirtual

This function calculates some frequently used values. The central density \(\rho_0\) is set by the normalization condition that the total mass equals one, which is straightforward for a Gaussian distribution,

\[ \rho_0 = \frac{1}{(2\pi)^{3/2}\,\sigma^3} .\]

This function also precalculates of a vector with the cumulative mass

\[ M(r) = 4\pi \int_0^r \rho(r')\, r'^2\, {\text{d}}r' \]

at a large number of radii. For the Gaussian distribution we find

\[ M(r) = \mathrm{erf}(t) - \frac{2}{\sqrt{\pi}} \,t \, \exp(-t^2) \quad\mathrm{with}\quad t = \frac{r}{\sqrt{2}\,\sigma} .\]

Reimplemented from SimulationItem.

◆ Sigmar()

double GaussianGeometry::Sigmar ( ) const
overridevirtual

This function returns the surface mass density along a radial line starting at the centre of the coordinate system, i.e.

\[ \Sigma_r = \int_0^\infty \rho(r)\,{\text{d}}r. \]

For a Gaussian geometry we easily find

\[ \Sigma_r = \frac{1}{4\pi\,\sigma^2}. \]

Implements SpheGeometry.


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