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The SKIRT project
advanced radiative transfer for astrophysics
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The SKIRT project
advanced radiative transfer for astrophysics
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#include <CubicalBackgroundSource.hpp>
Public Member Functions | |
| double | edgeLength () const |
| int | intrinsicDimension () const override |
| void | launchSpecialty (PhotonPacket *pp, size_t historyIndex, double lambda, double Lw, VelocityInterface *bvi) const override |
| Public Member Functions inherited from CenteredSource | |
| double | centerX () const |
| double | centerY () const |
| double | centerZ () const |
| int | geometryDimension () const override |
| Public Member Functions inherited from SpecialtySource | |
| int | dimension () const override |
| bool | hasVelocity () const override |
| void | launchNormalized (PhotonPacket *pp, size_t historyIndex, double lambda, double Lw) const override |
| Vec | velocity () const override |
| double | velocityX () const |
| double | velocityY () const |
| double | velocityZ () const |
| Public Member Functions inherited from NormalizedSource | |
| void | launch (PhotonPacket *pp, size_t historyIndex, double L) const override |
| double | luminosity () const override |
| LuminosityNormalization * | normalization () const |
| SED * | sed () const |
| double | specificLuminosity (double wavelength) const override |
| Range | wavelengthRange () const override |
| Public Member Functions inherited from Source | |
| virtual void | prepareForLaunch (double sourceBias, size_t firstIndex, size_t numIndices) |
| double | sourceWeight () const |
| double | wavelengthBias () const |
| WavelengthDistribution * | wavelengthBiasDistribution () 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 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 WavelengthRangeInterface | |
| virtual | ~WavelengthRangeInterface () |
| Public Member Functions inherited from VelocityInterface | |
| virtual | ~VelocityInterface () |
Protected Member Functions | |
| CubicalBackgroundSource () | |
| Protected Member Functions inherited from CenteredSource | |
| CenteredSource () | |
| Protected Member Functions inherited from SpecialtySource | |
| SpecialtySource () | |
| void | setupSelfBefore () override |
| Protected Member Functions inherited from NormalizedSource | |
| NormalizedSource () | |
| void | setupSelfAfter () override |
| Protected Member Functions inherited from Source | |
| Source () | |
| void | informAvailableWavelengthRange (Range available, string itemType) |
| Random * | random () const |
| Protected Member Functions inherited from SimulationItem | |
| SimulationItem () | |
| virtual bool | offersInterface (const std::type_info &interfaceTypeInfo) const |
| Protected Member Functions inherited from Item | |
| Item () | |
| Protected Member Functions inherited from SourceWavelengthRangeInterface | |
| SourceWavelengthRangeInterface () | |
| Protected Member Functions inherited from WavelengthRangeInterface | |
| WavelengthRangeInterface () | |
| Protected Member Functions inherited from VelocityInterface | |
| VelocityInterface () | |
Private Types | |
| using | BaseType |
| using | ItemType |
Private Attributes | |
| double | _edgeLength |
Friends | |
| class | ItemRegistry |
The CubicalBackgroundSource class represents the surface of a cube (i.e. the combination of the six walls) from which radiation escapes in the inward direction. The emissivity is anisotropic: there is no radiation outwards and the inward emissivity from each wall is proportional to \(\cos\theta'\), where \(\theta'\) is the angle between the direction and the normal on the wall.
When an item of this type is used, the names provided by the conditional value expression "Dimension3" are inserted into the name sets used for evaluating Boolean expressions.
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inlineprotected |
Default constructor for concrete Item subclass CubicalBackgroundSource: "a cubical background source with an anisotropic inward radiation field".
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inline |
This function returns the value of the discoverable double property edgeLength: "the edge length of the background cube".
This property represents a physical quantity of type "length".
The minimum value for this property is "]0".
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overridevirtual |
This function returns the intrinsic dimension of the geometry, which is 3 in this case.
Implements CenteredSource.
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overridevirtual |
This function causes the photon packet pp to be launched from the source using the given history index, wavelength, weighted luminosity contribution, and redshift interface (corresponding to the bulk velocity of the source).
Firstly, the function generates a random inward launch position \({\bf{r}}\) on the background surface. To accomplish this, it randomly selects one of the six cube walls (represented by its outward normal \({\bf{u}}\)), generates a random position within the selected wall, and transforms this position to take into account the background cube's size and center position.
Secondly, the function generates a random direction \({\bf{k}}\) appropriate for the anisotropic inward radiation field at the location \({\bf{r}}\), or equivalently, for the wall normal \({\bf{u}}\).
In a spherical coordinate system with the Z' axis normal to the surface at the position \({\bf{r}}\), the probability distribution is given by
\[ p(\theta',\varphi')\, {\text{d}}\theta'\, {\text{d}}\varphi' = -\frac{1}{\pi}\cos\theta' \sin\theta'\,{\text{d}}\theta'\, {\text{d}}\varphi' \qquad \frac{\pi}{2} \leq \theta' < \pi. \]
Random angles \(\theta'\) and \(\varphi'\) can be determined by taking two uniform deviates \({\cal{X}}_1\) and \({\cal{X}}_2\) and solving the two equations
\[\begin{split} {\cal{X}}_1 &= -\int_{\pi/2}^{\theta'} 2\sin\theta^{\prime\prime}\cos\theta^{\prime\prime}\,{\text{d}}\theta^{\prime\prime} \\ {\cal{X}}_2 &= \int_0^{\varphi'} \frac{{\text{d}}\varphi^{\prime\prime}}{2\pi} \end{split} \]
for \(\theta'\) and \(\varphi'\). The solution is readily found,
\[ \begin{split} \theta' &= \pi - \arccos \sqrt{{\cal{X}}_1} \\ \varphi' &= 2\pi\,{\cal{X}}_2. \end{split} \]
Once these values have been determined, we need to rotate such that the Z' axis is perpendicular to the wall corresponding to the position \({\bf{r}}\).
Thirdly, the function sets up a thread-local object that serves the angular distribution interface for a particular launch position. Configured with the appropriate launch wall normal \({\bf{u}}\), this object is handed to the photon packet being launched so that peel-off photon packets can retrieve the appropriate bias factor for the instrument direction. This works even if there are multiple sources of this type because each thread handles a single photon packet at a time.
The local angular distribution object implements a function that returns the normalized probability for a direction \({\bf{k}}\), given that the point of emission is defined by the normal \({\bf{u}}\). The appropriate probability distribution is given by
\[p({\bf{k}})\, {\text{d}}\Omega = \begin{cases} 0 & 0 \leq \theta' < \frac{\pi}{2} \\ -4\cos\theta'\, {\text{d}}\Omega & \frac{\pi}{2} \leq \theta' < \pi \end{cases} \]
Here \(\theta'\) is the angle between the direction \({\bf{k}}\) and the outward normal \({\bf{u}}\) of the launch wall, i.e.
\[ \cos\theta' = {\bf{k} \cdot \bf{r}}. \]
This distribution is correctly normalized in the sense that
\[ \frac{1}{4\pi} \iint p({\bf{k}})\, {\text{d}}\Omega = 1. \]
Finally, the function launches the photon packet, passing it all of the above information.
Implements SpecialtySource.