The SKIRT project
advanced radiative transfer for astrophysics
Sphere3DSpatialGrid Class Reference

#include <Sphere3DSpatialGrid.hpp>

Inheritance diagram for Sphere3DSpatialGrid:

Public Member Functions

int cellIndex (Position bfr) const override
Position centralPositionInCell (int m) const override
std::unique_ptr< PathSegmentGeneratorcreatePathSegmentGenerator () const override
double diagonal (int m) const override
int dimension () const override
MeshmeshAzimuthal () const
MeshmeshPolar () const
MeshmeshRadial () const
int numCells () const override
Position randomPositionInCell (int m) const override
void setupSelfAfter () override
double volume (int m) const override
Public Member Functions inherited from SphereSpatialGrid
Box boundingBox () const override
double maxRadius () const
double minRadius () const
Public Member Functions inherited from SpatialGrid
virtual void writeGridPlotFiles (const SimulationItem *probe) const
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

 Sphere3DSpatialGrid ()
void write_xy (SpatialGridPlotFile *outfile) const override
void write_xyz (SpatialGridPlotFile *outfile) const override
void write_xz (SpatialGridPlotFile *outfile) const override
void write_yz (SpatialGridPlotFile *outfile) const override
Protected Member Functions inherited from SphereSpatialGrid
 SphereSpatialGrid ()
void setupSelfBefore () override
Protected Member Functions inherited from SpatialGrid
 SpatialGrid ()
Randomrandom () const
Protected Member Functions inherited from SimulationItem
 SimulationItem ()
virtual bool offersInterface (const std::type_info &interfaceTypeInfo) const
Protected Member Functions inherited from Item
 Item ()

Private Types

using BaseType
using ItemType

Private Member Functions

bool getCoords (int m, double &rmin, double &thetamin, double &phimin, double &rmax, double &thetamax, double &phimax) const
int index (int i, int j, int k) const

Private Attributes

Array _cosv
Array _cv
double _eps
Mesh_meshAzimuthal
Mesh_meshPolar
Mesh_meshRadial
int _Ncells
int _Nphi
int _Nr
int _Ntheta
Array _phiv
Array _rv
Array _sinv
Array _thetav

Friends

class ItemRegistry
class MySegmentGenerator

Additional Inherited Members

Static Protected Member Functions inherited from SphereSpatialGrid
static int initPolarGrid (Array &thetav, Array &cosv, const Mesh *mesh)

Detailed Description

The Sphere3DSpatialGrid class is subclass of the SphereSpatialGrid class, and represents a fully three-dimensional spatial grid based on spherical coordinates. The grid is specified through three sets of grid points:

  • \(N_r+1\) radial grid points \(r_i, \,i=0,\ldots,N_r\), with \(0\le r_\text{min} = r_0\), \(r_i<r_{i+1}\), and \(r_{N_r} = r_\text{max}\).
  • \(N_\theta+1\) polar-inclination grid points \(\theta_j, \,j=0,\ldots,N_\theta\) with \(0=\theta_0\), \(\theta_j<\theta_{j+1}\), and \(\theta_{N_\theta}=\pi\).
  • \(N_\varphi+1\) azimuthal grid points \(\varphi_k, \,k=0,\ldots,N_\varphi\), with \(-\pi=\varphi_0\), \(0<\varphi_{k+1}-\varphi_k\le2\pi/3\), and \(\varphi_{N_\varphi}=\pi\). The maximum limit on azimuth bin width is imposed to avoid confusion between the meridional half-planes when detecting cell border limits.
Note
The algorithm used by the path segment generator in this class requires that the xy-plane \(\theta=\pi/2\) is included in the polar grid. If this is not the case, this point is automatically added, increasing the number of polar bins by one.

In total there are \(N_{\text{cells}} = N_r\,N_\theta\,N_\varphi\) cells in the grid.

This item type is displayed only if the Boolean expression "Level2" evaluates to true after replacing the names by true or false depending on their presence.

Constructor & Destructor Documentation

◆ Sphere3DSpatialGrid()

Sphere3DSpatialGrid::Sphere3DSpatialGrid ( )
inlineprotected

Default constructor for concrete Item subclass Sphere3DSpatialGrid: "a 3D spatial grid in spherical coordinates".

Member Function Documentation

◆ cellIndex()

int Sphere3DSpatialGrid::cellIndex ( Position bfr) const
overridevirtual

This function returns the index \(m\) of the cell that contains the position \({\bf{r}}\). It determines the 3D bin indices \(i,j,k\) of the cell containing the position and calculates the correct cell index based on these three numbers.

Implements SpatialGrid.

◆ centralPositionInCell()

Position Sphere3DSpatialGrid::centralPositionInCell ( int m) const
overridevirtual

This function returns the central location of the cell with index \(m\). It determines the 3D bin indices \(i,j,k\) corresponding to the cell index \(m\). The spherical coordinates of the central position are subsequently determined from

\[ \begin{split} r &= \frac{r_i + r_{i+1}}{2} \\ \theta &= \frac{\theta_j + \theta_{j+1}}{2} \\ \varphi &= \frac{\varphi_k + \varphi_{k+1}}{2}. \end{split} \]

Implements SpatialGrid.

◆ createPathSegmentGenerator()

std::unique_ptr< PathSegmentGenerator > Sphere3DSpatialGrid::createPathSegmentGenerator ( ) const
overridevirtual

This function creates and hands over ownership of a path segment generator (an instance of a PathSegmentGenerator subclass) appropriate for a 3D spherical grid, implemented as a private PathSegmentGenerator subclass.

We represent the path by its parameter equation \({\bf{x}}={\bf{r}}+s\,{\bf{k}}\), and we assume that \({\bf{k}}\) is a unit vector. The two intersection points with a radial boundary sphere \({\bf{x}}^2=r_*^2\) are obtained by solving the quadratic equation \(s^2 + 2\,({\bf{r}}\cdot{\bf{k}})\,s + ({\bf{r}}^2-r_*^2)=0\) for \(s\).

The two intersection points with an angular boundary cone \(x_z^2=c^2\,{\bf{x}}^2\) (with \(c=\cos\theta_*\)) are obtained by solving the quadratic equation \((c^2-k_z^2)\,s^2 + 2\,(c^2\,{\bf{r}}\cdot{\bf{k}}-r_z k_z)\,s + (c^2\,{\bf{r}}^2-r_z^2)=0\) for \(s\). The intersection points with the reflected cone are always more distant than the other cell boundaries (the requirement to include the xy-plane \(\theta=\pi/2\) in the grid ensures that this is true) and thus these phantom points are automatically ignored.

The intersection point with a meriodonal plane \(\sin\varphi_* x = \cos\varphi_* y\) is obtained by

\[ s = -\;\frac{r_\text{x}\sin\varphi_* - r_\text{y}\cos\varphi_*} {k_\text{x}\sin\varphi_* - k_\text{y}\cos\varphi_*} \]

The requirement that \(\varphi_{j+1}-\varphi_j\le2\pi/3\) ensures that the intersection point with the reflected half-plane is always more distant than the other cell boundaries thus that phantom point is automatically ignored.

The segment generator progresses the starting point of the path through the grid along the path's direction. For each step along the way, it calculates the distances to the intersections with all candidate borders of the current cell, and then selects the nearest intersection point.

Implements SpatialGrid.

◆ diagonal()

double Sphere3DSpatialGrid::diagonal ( int m) const
overridevirtual

This function returns the "diagonal" of the cell with index \(m\). It determines the 3D bin indices \(i,j,k\) corresponding to the cell index \(m\), and then calculates the distance between the outer/upper and inner/lower corners of the cell, i.e. between the points \(\{ r_i,\theta_j,\varphi_k \}\) and \(\{ r_{i+1},\theta_{j+1},\varphi_{k+1} \}\).

Implements SpatialGrid.

◆ dimension()

int Sphere3DSpatialGrid::dimension ( ) const
overridevirtual

This function returns the dimension of the grid, which is 3.

Implements SpatialGrid.

◆ getCoords()

bool Sphere3DSpatialGrid::getCoords ( int m,
double & rmin,
double & thetamin,
double & phimin,
double & rmax,
double & thetamax,
double & phimax ) const
private

This function obtains the spherical coordinates for the corners of the cell with index \(m\). It determines the radial, polar and azimuthal bin indices \(i\), \(j\) and \(k\) corresponding to the cell index \(m\) using the formulae

\[ \begin{split} i &= \lfloor m/(N_\theta\,N_\varphi) \rfloor \\ j &= \lfloor m/N_\varphi \rfloor \,\text{mod}\, N_\theta \\ k &= m\,\text{mod}\,N_\varphi. \end{split} \]

If all of the resulting bin indices are within range, the function stores the corresponding cell corner coordinates in the provided arguments and returns true. If any of the indices are out of range, the function returns false and the contents of the provided arguments remains unchanged.

◆ index()

int Sphere3DSpatialGrid::index ( int i,
int j,
int k ) const
private

This private function returns the cell index corresponding to the radial index \(i\), the polar index \(j\), and azimuthal index \(k\). The correspondence is \(m=k+j\,N_\varphi+i\,N_\theta\,N_\varphi\).

◆ meshAzimuthal()

Mesh * Sphere3DSpatialGrid::meshAzimuthal ( ) const
inline

This function returns the value of the discoverable item property meshAzimuthal: "the bin distribution in the azimuthal direction".

The default value for this property is given by the conditional value expression "LinMesh".

◆ meshPolar()

Mesh * Sphere3DSpatialGrid::meshPolar ( ) const
inline

This function returns the value of the discoverable item property meshPolar: "the bin distribution in the polar direction".

The default value for this property is given by the conditional value expression "LinMesh".

◆ meshRadial()

Mesh * Sphere3DSpatialGrid::meshRadial ( ) const
inline

This function returns the value of the discoverable item property meshRadial: "the bin distribution in the radial direction".

The default value for this property is given by the conditional value expression "LinMesh".

◆ numCells()

int Sphere3DSpatialGrid::numCells ( ) const
overridevirtual

This function returns the number of cells \(N_r\,N_\theta\,N_\varphi\) in the grid.

Implements SpatialGrid.

◆ randomPositionInCell()

Position Sphere3DSpatialGrid::randomPositionInCell ( int m) const
overridevirtual

This function returns a random location in the cell with index \(m\). It determines the 3D bin indices \(i,j,k\) corresponding to the cell index \(m\). Then a random radius \(r\), a random inclination \(\theta\), and a random azimuth \(\varphi\) are determined using

\[ \begin{split} r &= \left( r_i^3 + {\cal{X}}_1\,(r_{i+1}^3-r_i^3) \right)^{1/3} \\ \cos\theta &= \cos\theta_j + {\cal{X}}_2\, (\cos\theta_{j+1}-\cos\theta_j) \\ \varphi &= \varphi_k + {\cal{X}}_3\, (\varphi_{k+1}-\varphi_k), \end{split} \]

with \({\cal{X}}_1\), \({\cal{X}}_2\) and \({\cal{X}}_3\) three uniform deviates.

Implements SpatialGrid.

◆ setupSelfAfter()

void Sphere3DSpatialGrid::setupSelfAfter ( )
overridevirtual

This function sets up a number of data members. It precomputes and stores cosine values for the polar grid points and sine and cosine values for the azimuthal grid points. It further ensures that the grid points conform to the requirements described in the class header.

Reimplemented from SimulationItem.

◆ volume()

double Sphere3DSpatialGrid::volume ( int m) const
overridevirtual

This function returns the volume of the cell with index \(m\). It determines the 3D bin indices \(i,j,k\) corresponding to the cell index \(m\), and then calculates the volume as

\[ V = \frac{1}{3} \left(r_{i+1}^3-r_i^3\right) \left(\cos\theta_j-\cos\theta_{j+1}\right) \left(\varphi_{k+1}-\varphi_k\right). \]

Implements SpatialGrid.

◆ write_xy()

void Sphere3DSpatialGrid::write_xy ( SpatialGridPlotFile * outfile) const
overrideprotectedvirtual

This function writes the intersection of the grid with the xy plane to the specified SpatialGridPlotFile object.

Reimplemented from SpatialGrid.

◆ write_xyz()

void Sphere3DSpatialGrid::write_xyz ( SpatialGridPlotFile * outfile) const
overrideprotectedvirtual

This function writes 3D information for all or part of the cells in the grid structure to the specified SpatialGridPlotFile object.

Reimplemented from SpatialGrid.

◆ write_xz()

void Sphere3DSpatialGrid::write_xz ( SpatialGridPlotFile * outfile) const
overrideprotectedvirtual

This function writes the intersection of the grid with the xz plane to the specified SpatialGridPlotFile object.

Reimplemented from SpatialGrid.

◆ write_yz()

void Sphere3DSpatialGrid::write_yz ( SpatialGridPlotFile * outfile) const
overrideprotectedvirtual

This function writes the intersection of the grid with the yz plane to the specified SpatialGridPlotFile object.

Reimplemented from SpatialGrid.


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