Gyoto
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Astronomical objects defined bya a potential/distance. More...
#include <GyotoStandardAstrobj.h>
Public Member Functions | |
Standard () | |
Default constructor. | |
Standard (double radmax) | |
Set rmax in constructor. | |
Standard (std::string kind) | |
Set kind in constructor. | |
Standard (const Standard &) | |
Copy constructor. | |
virtual | ~Standard () |
Destructor: does nothing. | |
virtual void | setSafetyValue (double val) |
virtual double | getSafetyValue () const |
virtual int | Impact (Gyoto::Photon *ph, size_t index, Astrobj::Properties *data=NULL) |
does a photon at these coordinates impact the object? | |
virtual double | operator() (double const coord[4])=0 |
virtual void | getVelocity (double const pos[4], double vel[4])=0 |
virtual double | giveDelta (double coord[8]) |
virtual int | setParameter (std::string name, std::string content) |
Called from setParameters() | |
virtual void | fillElement (FactoryMessenger *fmp) const |
called from Factory | |
virtual Generic * | clone () const =0 |
"Virtual" copy constructor | |
virtual SmartPointer < Metric::Generic > | getMetric () const |
virtual void | setMetric (SmartPointer< Metric::Generic >) |
virtual double | getRmax () |
Get maximal distance from center of coordinate system. | |
const std::string | getKind () const |
Get the kind of the Astrobj (e.g. "Star") | |
virtual void | setRmax (double val) |
Set maximal distance from center of coordinate system. | |
virtual void | unsetRmax () |
Set rmax_set_ to 0. | |
void | setFlag_radtransf (int flag) |
Set whether the object is optically thin. | |
int | getFlag_radtransf () const |
Query whether object is optically thin. | |
virtual Quantity_t | getDefaultQuantities () |
virtual void | setParameters (FactoryMessenger *fmp) |
Main loop in Subcontractor_t function. | |
virtual void | processHitQuantities (Photon *ph, double *coord_ph_hit, double *coord_obj_hit, double dt, Astrobj::Properties *data) const |
virtual double | emission (double nu_em, double dsem, double coord_ph[8], double coord_obj[8]=NULL) const |
INVARIANT emission j_{}/^{2}. | |
virtual double | integrateEmission (double nu1, double nu2, double dsem, double c_ph[8], double c_obj[8]=NULL) const |
^nu2 I_nu dnu (or j_nu) | |
virtual double | transmission (double nuem, double dsem, double coord[8]) const |
Transmission: exp( {} * dsem ) | |
void | checkPhiTheta (double coord[8]) const |
virtual double | operator() (double const data[])=0 |
Protected Types | |
typedef Gyoto::SmartPointer < Gyoto::SmartPointee > | Subcontractor_t (Gyoto::FactoryMessenger *) |
A subcontractor builds an object upon order from the Factory. |
Protected Member Functions | |
void | incRefCount () |
Increment the reference counter. Warning: Don't mess with the counter. | |
int | decRefCount () |
Decrement the reference counter and return current value. Warning: Don't mess with the counter. | |
int | getRefCount () |
Get the current number of references. |
Protected Attributes | |
double | critical_value_ |
see operator()(double const coord[4]) const | |
double | safety_value_ |
see operator()(double const coord[4]) const | |
SmartPointer < Gyoto::Metric::Generic > | gg_ |
double | rmax_ |
Maximum distance to the center of the coordinate system. | |
int | rmax_set_ |
Never recompute rmax: it was externally set. | |
const std::string | kind_ |
Kind of object (e.g. "Star"...) | |
int | flag_radtransf_ |
1 if radiative transfer inside Astrobj, else 0 |
Friends | |
class | Gyoto::SmartPointer< Gyoto::Astrobj::Standard > |
Astronomical objects defined bya a potential/distance.
Many geometrically thick objects can be defined by the value of a function of the 4 coordinates, and their emission can often be defined in terms of an emission law and of a transmission law.
This is a base class for this standard case which simplifies a lot writting new Astrobjs.
It is either to implement a sub-class of Astrobj::Standard than a sub-class of Astrobj::Generic. In particular, there is no need to implement the Generic::Impact() function. Instead, one needs to implement a few much simpler functions and most of the complex ray-tracing algorithms and heuristics is implemented in Standard::Impact(). It is recommended to read first the introduction in the Gyoto::Astrobj namespace documentation.
The geometrical shape of a Gyoto::Astrobj::Standard object is yielded by a function of the 4 position vector. This function is implemented as operator()(). The velocity field of the fluid is implemented in the getVelocity() method. The emission(), integrateEmission() and transmission() methods implement the radiative transfer primitives for this object. Finally, you may choose to reimplement processHitQuantities() and Impact(), but this should not be necessary (that is the all point of the Standard class).
Like any other Astrobj::Generic sub-classes, an Astrobj::Standard subclass should register an Astrobj::Subcontractor_t function using the Astrobj::Register() function. See also Writing plug-ins for Gyoto .
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inherited |
A subcontractor builds an object upon order from the Factory.
Various classes need to provide a subcontractor to be able to instanciate themselves upon order from the Factory. A subcontractor is a function (often a static member function) which accepts a pointer to a FactoryMessenger as unique parameter, communicates with the Factory using this messenger to read an XML description of the object to build, and returns this objet. SmartPointee::Subcontractor_t* is just generic enough a typedef to cast to and from other subcontractor types: Astrobj::Subcontractor_t, Metric::Subcontractor_t, Spectrum::Subcontractor_t. A subcontractor needs to be registered using the relevant Register() function: Astrobj::Register(), Metric::Register(), Spectrum::Register().
Gyoto::Astrobj::Standard::Standard | ( | ) |
Default constructor.
kind_ = "Default", rmax_ = 0., rmax_set_ = 0.
Gyoto::Astrobj::Standard::Standard | ( | double | radmax | ) |
Set rmax in constructor.
kind_ = "Default", rmax_ = radmax, rmax_set_ = 1.
Gyoto::Astrobj::Standard::Standard | ( | std::string | kind | ) |
Set kind in constructor.
kind_ = kind, rmax_ = 0., rmax_set_ = 0.
Gyoto::Astrobj::Standard::Standard | ( | const Standard & | ) |
Copy constructor.
Make a deep copy of an Astrobj::Standard instance
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inherited |
checkPhiTheta() Modifies coord if the corrdinates are spherical-like so that coord[2]=theta is in [0,pi] and coord[3]=phi is in [0,2pi]. Important to use in all astrobj in spherical coordinates to prevent "z-axis problems".
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pure virtualinherited |
"Virtual" copy constructor
This method must be implemented by the various Astrobj::Generic subclasses in order to support cloning:
Implementing it is very straightforward, as long as the copy constructor Generic(const Generic& ) has been implemented:
Implemented in Gyoto::Astrobj::Star, Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::Disk3D, Gyoto::Astrobj::ThinDisk, Gyoto::Astrobj::DynamicalDisk, Gyoto::Astrobj::Complex, Gyoto::Astrobj::Disk3D_BB, Gyoto::Astrobj::Torus, Gyoto::Astrobj::PageThorneDisk, Gyoto::Astrobj::ThinDiskPL, Gyoto::Astrobj::PatternDiskBB, and Gyoto::Astrobj::FixedStar.
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virtualinherited |
INVARIANT emission j_{}/^{2}.
Called by the default implementation for processHitQuantities().
emission() computes the intensity I_nu emitted by the small volume of length dsem. It should take self-absorption along dsem into account.
Reminder :
The equation used for radiative transfer (without absorption) is: d(I_nu/nu^3)/dlambda = (j_nu/nu^2) [*] where lambda is the integration parameter along the null geodesic.
NB: Let us consider a particular observer, with nu being the frequency measured by this observer, and ds being the proper distance (as measured by the observer) that the photon travels as it moves from lambda to lambda+dlambda along its geodesic. Then it can be shown that : dlambda = ds/nu This shows that Eq. [*] is homogeneous.
The default implementation returns 1. if optically thick and dsem if optically thin. It allows for a quick implementation of your object for visualization purposes.
nu_em | Frequency at emission |
dsem | length over which to integrate inside the object |
coord_ph | Photon coordinate |
coord_obj | Emitter coordinate at current photon position |
Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Torus, Gyoto::Astrobj::DynamicalDisk, Gyoto::Astrobj::Disk3D_BB, Gyoto::Astrobj::PageThorneDisk, Gyoto::Astrobj::PatternDiskBB, and Gyoto::Astrobj::ThinDiskPL.
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virtual |
called from Factory
Astrobj implementations should impement fillElement to save their parameters to XML and call the generic implementation to save generic parts such as Flag_radtrans: Generic::fillElement(fmp).
Reimplemented from Gyoto::Astrobj::Generic.
Reimplemented in Gyoto::Astrobj::Star, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::FixedStar.
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virtualinherited |
Return a Gyoto::Quantity_t suitable as input to Gyoto::Scenery::setRequestedQuantities() to set de default quantities to compute for this object. The default of these defaults GYOTO_QUANTITY_INTENSITY.
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inherited |
Query whether object is optically thin.
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virtualinherited |
Get the Metric
Reimplemented in Gyoto::Astrobj::Star.
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virtualinherited |
Get maximal distance from center of coordinate system.
Get maximal distance from center of coordinate system at which a Photon may hit the object.
Child classes may use the rmax_ member to cache this value.
It can also be set using setRmax(). If setRmax has been used to set rmax_, getRmax() must not recompute it.
Reimplemented in Gyoto::Astrobj::Star, and Gyoto::Astrobj::Torus.
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pure virtual |
Used by Standard::Impact().
Fill vel with the 4-vector velocity of the fluid at 4-position pos.
pos | input, 4-position at which to compute velocity; |
vel | output, 4-velocity at pos. |
Implemented in Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Star, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::FixedStar.
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virtual |
Used by Standard::Impact().
Gives the requested integration step delta_t (in coordinate time t) between two neighbooring points along a portion of geodesic inside an astrobj
coord | input coordinate at which delta_t is given |
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virtual |
does a photon at these coordinates impact the object?
Impact() checks whether a Photon impacts the object between two integration steps of the photon's trajectory (those two steps are photon->getCoord(index, coord1) and photon->getCoord(index+1, coord2)). Impact returns 1 if the photon impacts the object between these two steps, else 0. In many cases of geometrically thick obects, the implementation Astrobj::Standard::Impact() will be fine.
Impact will call Generic::processHitQuantities() (which is virtual and may be re-implemented) to compute observable properties on demand: if the data pointer is non-NULL, the object will look in it for pointers to properties which apply to its kind. If a pointer to a property known to this object is present, then the property is computed and store at the pointed-to adress. For instance, all objects know the "intensity" property. If data->intensity != NULL, the instensity is computed and stored in *data->intensity.
If data is non-NULL and only in this case, processHitQuantities() will also call ph->transmit() to update the transmissions of the Photon (see Photon::transmit(size_t, double)). This must not be done if data is NULL (see Astrobj::Complex::Impact() for an explanation).
ph | Gyoto::Photon aimed at the object; |
index | Index of the last photon step; |
data | Pointer to a structure to hold the observables at impact. |
Implements Gyoto::Astrobj::Generic.
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virtualinherited |
^nu2 I_nu dnu (or j_nu)
Compute the integral of emission() from nu1 to nu2. The default implementation is a numerical integrator which works well enough and is reasonably fast if emission() is a smooth function (i.e. no emission or absorption lines). If possible, it is wise to implement an analytical solution. It is used by processHitQuantities to compute the "BinSpectrum" quantity which is the most physical: it is the only quantity that can be actually measured directly by a real-life instrument.
Reimplemented in Gyoto::Astrobj::UniformSphere, and Gyoto::Astrobj::Torus.
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pure virtual |
A potential, distance, or whatever function such that operator()(double coord[4]) < critical_value_ if and only if coord is inside the object. This function is used by the default implmenetation of Impact(). If Impact() is overloaded, it is not necessary to overload operator()(double coord[4]). The default implementation throws an error.
Implemented in Gyoto::Astrobj::UniformSphere, and Gyoto::Astrobj::Torus.
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virtualinherited |
processHitQuantities fills the requested data in Impact. To use it, you need to call it in the Impact() method for your object in case of hit. It will fill Redshift, Intensity, Spectrum, BinSpectrum and update the Photon's transmission by calling Photon::transmi(), only if data==NULL.
You can overload it for your Astrobj. The generic implementation calls emission(), integrateEmission() and transmission() below.
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inherited |
Set whether the object is optically thin.
Set flag indicating that radiative transfer should be integrated, i.e. the object is to be considered optically thin.
flag,: | 1 if optically thin, 0 if optically thick. |
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virtualinherited |
Set the Metric
Reimplemented in Gyoto::Astrobj::Star, Gyoto::Astrobj::Complex, Gyoto::Astrobj::Disk3D_BB, Gyoto::Astrobj::PatternDiskBB, Gyoto::Astrobj::FixedStar, and Gyoto::Astrobj::PageThorneDisk.
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virtual |
Called from setParameters()
Assume MyKind is a sublcass of Astrobj::Generic which has towo members (a string StringMember and a double DoubleMember):
If MyKind is not a direct subclass of Generic but is a subclass of e.g. Standard, UniformSphere of ThinDisk, it should call the corresponding setParameter() implementation instead of Generic::setParameter().
name | XML name of the parameter |
content | string representation of the value |
Reimplemented from Gyoto::Astrobj::Generic.
Reimplemented in Gyoto::Astrobj::Star, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::FixedStar.
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virtualinherited |
Main loop in Subcontractor_t function.
The Subcontractor_t function for each Astrobj kind should look somewhat like this:
Each object kind should implement setParameter(string name, string content) to interpret the individual XML elements. setParameters() can be overloaded in case the specific Astrobj class needs low level access to the FactoryMessenger. See UniformSphere::setParameters().
Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::Disk3D, Gyoto::Astrobj::Star, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Complex, and Gyoto::Astrobj::Torus.
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virtualinherited |
Set maximal distance from center of coordinate system.
Set maximal distance from center of coordinate system at which a Photon may hit the object.
Side effect: set rmax_set_ to 1.
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virtualinherited |
Transmission: exp( {} * dsem )
transmission() computes the transmission of this fluid element or 0 if optically thick. The default implementation returns 1. (no attenuation) if optically thin, 0. if optically thick.
nuem | frequency in the fluid's frame |
coord | Photon coordinate |
dsem | geometrical length in geometrical units |
Reimplemented in Gyoto::Astrobj::PatternDisk, and Gyoto::Astrobj::Torus.
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virtualinherited |
Set rmax_set_ to 0.
getRmax() will then be free to recompute rmax_. Astrobjs which cache rmax_ may need to update it when unsetRmax() is called.
Reimplemented in Gyoto::Astrobj::Star.
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protectedinherited |
The Metric in this end of the Universe
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protectedinherited |
Kind of object (e.g. "Star"...)
The kind should match the name of the class, e.g. "Star" for a Gyoto::Star.
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protectedinherited |
Maximum distance to the center of the coordinate system.
Maximum distance from the center of the coordinate system at which a photon may hit the object. Child classes may choose to update rmax at all time or to use it to cache the value, for instance when getRmax() is called. External classes (Photons in particular) must use getRmax() to access this information.
rmax_set_==1 means that rmax_ was set using setRmax() or the constructor. In this case, getRmax() must always return this value, not recompute it.
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protectedinherited |
Never recompute rmax: it was externally set.
rmax_set_==1 means that rmax_ was set using setRmax() or the constructor. In this case, getRmax() must always return this value, not recompute it.
Use unsetRmax() to reset rmax_set_ to 0.