Gyoto
Public Member Functions | Protected Types | Protected Member Functions | Protected Attributes | Friends | List of all members
Gyoto::Astrobj::Standard Class Referenceabstract

Astronomical objects defined bya a potential/distance. More...

#include <GyotoStandardAstrobj.h>

Inheritance diagram for Gyoto::Astrobj::Standard:
Gyoto::Astrobj::Generic Gyoto::Functor::Double_constDoubleArray Gyoto::SmartPointee Gyoto::Astrobj::PolishDoughnut Gyoto::Astrobj::Torus Gyoto::Astrobj::UniformSphere Gyoto::Astrobj::FixedStar Gyoto::Astrobj::Star Gyoto::Astrobj::StarTrace

Public Member Functions

 Standard ()
 Default constructor. More...
 
 Standard (double radmax)
 Set rmax in constructor. More...
 
 Standard (std::string kind)
 Set kind in constructor. More...
 
 Standard (const Standard &)
 Copy constructor. More...
 
virtual ~Standard ()
 Destructor: does nothing.
 
virtual void setSafetyValue (double val)
 Set Standard::safety_value_.
 
virtual double getSafetyValue () const
 Get Standard::safety_value_.
 
virtual int Impact (Gyoto::Photon *ph, size_t index, Astrobj::Properties *data=NULL)
 Does a photon at these coordinates impact the object? More...
 
virtual double operator() (double const coord[4])=0
 Function defining the object interior. More...
 
virtual void getVelocity (double const pos[4], double vel[4])=0
 Fluid velocity field. More...
 
virtual double giveDelta (double coord[8])
 Maximum δ inside object. More...
 
virtual int setParameter (std::string name, std::string content, std::string unit="")
 Set parameter by name. More...
 
virtual void fillElement (FactoryMessenger *fmp) const
 Fill XML section. More...
 
virtual Genericclone () const =0
 Cloner. More...
 
virtual SmartPointer
< Metric::Generic
metric () const
 Get the Metric gg_.
 
virtual void metric (SmartPointer< Metric::Generic >)
 Set the Metric gg_.
 
virtual double rMax ()
 Get maximal distance from center of coordinate system. More...
 
virtual double rMax (std::string unit)
 Get rmax_ is specified unit. More...
 
virtual void rMax (double val)
 Set maximal distance from center of coordinate system. More...
 
virtual void rMax (double val, std::string unit)
 Set maximal distance from center of coordinate system. More...
 
virtual double deltaMax (double coord[8])
 Get max step constraint for adaptive integration. More...
 
const std::string kind () const
 Get the kind of the Astrobj (e.g. "Star")
 
virtual void unsetRmax ()
 Set rmax_set_ to 0. More...
 
void opticallyThin (int flag)
 Set whether the object is optically thin. More...
 
int opticallyThin () const
 Query whether object is optically thin. More...
 
virtual Quantity_t getDefaultQuantities ()
 Which quantities to compute if know was requested. More...
 
virtual void setParameters (FactoryMessenger *fmp)
 Main loop in Subcontractor_t function. More...
 
virtual void processHitQuantities (Photon *ph, double *coord_ph_hit, double *coord_obj_hit, double dt, Astrobj::Properties *data) const
 Fills Astrobj::Properties. More...
 
virtual double emission (double nu_em, double dsem, double coord_ph[8], double coord_obj[8]=NULL) const
 Specific intensity Iν More...
 
virtual void emission (double Inu[], double nu_em[], size_t nbnu, double dsem, double coord_ph[8], double coord_obj[8]=NULL) const
 Specific intensity Iν for several values of νem More...
 
virtual double integrateEmission (double nu1, double nu2, double dsem, double c_ph[8], double c_obj[8]=NULL) const
 ν1ν2 Iν dν (or jν) More...
 
virtual void integrateEmission (double *I, double const *boundaries, size_t const *chaninds, size_t nbnu, double dsem, double *cph, double *co) const
 ν1ν2 Iν dν (or jν) More...
 
virtual double transmission (double nuem, double dsem, double coord[8]) const
 Transmission: exp( αν * dsem ) More...
 
virtual double operator() (double const data[])=0
 The actual function.
 

Protected Types

typedef Gyoto::SmartPointer
< Gyoto::SmartPointee
Subcontractor_t (Gyoto::FactoryMessenger *)
 A subcontractor builds an object upon order from the Factory. More...
 

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])
 
double safety_value_
 See operator()(double const coord[4])
 
SmartPointer
< Gyoto::Metric::Generic
gg_
 The Metric in this end of the Universe.
 
double rmax_
 Maximum distance to the center of the coordinate system [geometrical units]. More...
 
int rmax_set_
 Never recompute rmax: it was externally set. More...
 
std::string kind_
 Kind of object (e.g. "Star"...) More...
 
int flag_radtransf_
 1 if radiative transfer inside Astrobj, else 0
 

Friends

class Gyoto::SmartPointer< Gyoto::Astrobj::Standard >
 

Detailed Description

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 .

Member Typedef Documentation

typedef Gyoto::SmartPointer<Gyoto::SmartPointee> Gyoto::SmartPointee::Subcontractor_t(Gyoto::FactoryMessenger *)
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().

Constructor & Destructor Documentation

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

Member Function Documentation

virtual Generic* Gyoto::Astrobj::Generic::clone ( ) const
pure virtualinherited

Cloner.

This method must be implemented by the various Astrobj::Generic subclasses in order to support cloning:

SmartPointer<Astrobj> deep_copy = original->clone();

Cloning is necessary for multi-threading, recommended for interaction with the Yorick plug-in etc.

Implementing it is very straightforward, as long as the copy constructor Generic(const Generic& ) has been implemented:

MyAstrobj* MyAstrobj::clone() const { return new MyAstrobj(*this); }

Implemented in Gyoto::Astrobj::Star, Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::Disk3D, Gyoto::Astrobj::StarTrace, Gyoto::Astrobj::DynamicalDisk3D, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::DynamicalDisk, Gyoto::Astrobj::ThinDisk, Gyoto::Astrobj::Complex, Gyoto::Astrobj::PageThorneDisk, Gyoto::Astrobj::DirectionalDisk, Gyoto::Astrobj::PatternDiskBB, Gyoto::Astrobj::Torus, Gyoto::Astrobj::ThinDiskPL, Gyoto::Astrobj::FixedStar, and Gyoto::Astrobj::ThinDiskIronLine.

virtual double Gyoto::Astrobj::Generic::deltaMax ( double  coord[8])
virtualinherited

Get max step constraint for adaptive integration.

Parameters
[in]coordposition
Returns
max step to find this object reliably

Reimplemented in Gyoto::Astrobj::Complex.

virtual double Gyoto::Astrobj::Generic::emission ( double  nu_em,
double  dsem,
double  coord_ph[8],
double  coord_obj[8] = NULL 
) const
virtualinherited

Specific intensity Iν

Called by the default implementation for processHitQuantities().

emission() computes the intensity Iν emitted by the small volume of length dsem, in the emitter's frame. It should take self-absorption along dsem into account.

Reminder :

  • intensity = Iν [J m^-2 s^-1 ster^-1 Hz^-1];
  • invariant intensity = Iν3, which has the same value in any frame;
  • emission coefficient = jν [J m^-3 s^-1 ster^-1 Hz^-1] , defined by dIν = jν*ds, where ds is the distance travelled by the photon inside the object;
  • invariant emission coef = jν2, which has the same value in any frame.

The equation used for radiative transfer (without absorption) is:

d(Iν3)/dλ = (jν2) [*]

where λ is the integration parameter along the null geodesic.

NB: Let us consider a particular observer, with ν 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 λ to λ+dλ along its geodesic. Then it can be shown that:

dλ = ds/ν

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.

Parameters
nu_emFrequency at emission [Hz]
dsemlength over which to integrate inside the object [geometrical units]
coord_phPhoton coordinate
coord_objEmitter coordinate at current photon position

Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::Torus, Gyoto::Astrobj::DirectionalDisk, Gyoto::Astrobj::DynamicalDisk3D, Gyoto::Astrobj::DynamicalDisk, Gyoto::Astrobj::PageThorneDisk, Gyoto::Astrobj::PatternDiskBB, Gyoto::Astrobj::ThinDiskPL, and Gyoto::Astrobj::ThinDiskIronLine.

virtual void Gyoto::Astrobj::Generic::emission ( double  Inu[],
double  nu_em[],
size_t  nbnu,
double  dsem,
double  coord_ph[8],
double  coord_obj[8] = NULL 
) const
virtualinherited

Specific intensity Iν for several values of νem

Called by the default implementation for processHitQuantities().

emission() computes the intensity Iν emitted by the small volume of length dsem. It should take self-absorption along dsem into account.

Same as emission(double nu_em, double dsem, double coord_ph[8], double coord_obj[8]=NULL) const looping on several values of nu_em.

Parameters
Inu[nbnu]Output (must be set to a previously allocated array of doubles)
nu_em[nbnu]Frequencies at emission
nbnuSize of Inu[] and nu_em[]
dsemLength over which to integrate inside the object
coord_phPhoton coordinate
coord_objEmitter coordinate at current photon position
Returns
Iν or dIν [W m-2 sr-2]

Reimplemented in Gyoto::Astrobj::PolishDoughnut.

virtual void Gyoto::Astrobj::Standard::fillElement ( FactoryMessenger *  fmp) const
virtual

Fill XML section.

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::UniformSphere, Gyoto::Astrobj::Star, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::StarTrace.

virtual Quantity_t Gyoto::Astrobj::Generic::getDefaultQuantities ( )
virtualinherited

Which quantities to compute if know was requested.

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.

Reimplemented in Gyoto::Astrobj::PageThorneDisk.

virtual void Gyoto::Astrobj::Standard::getVelocity ( double const  pos[4],
double  vel[4] 
)
pure virtual

Fluid velocity field.

Fill vel with the 4-vector velocity of the fluid at 4-position pos.

Parameters
[in]pos4-position at which to compute velocity;
[out]vel4-velocity at pos.

Implemented in Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::Star, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::FixedStar.

virtual double Gyoto::Astrobj::Standard::giveDelta ( double  coord[8])
virtual

Maximum δ inside object.

Gives the requested integration step δt (in coordinate time t) between two neighbooring points along a portion of geodesic inside an astrobj

Parameters
coordinput coordinate at which δt is given
virtual int Gyoto::Astrobj::Standard::Impact ( Gyoto::Photon ph,
size_t  index,
Astrobj::Properties data = NULL 
)
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).

Parameters
phGyoto::Photon aimed at the object;
indexIndex of the last photon step;
dataPointer to a structure to hold the observables at impact.
Returns
1 if impact, 0 if not.

Implements Gyoto::Astrobj::Generic.

Reimplemented in Gyoto::Astrobj::PolishDoughnut.

virtual double Gyoto::Astrobj::Generic::integrateEmission ( double  nu1,
double  nu2,
double  dsem,
double  c_ph[8],
double  c_obj[8] = NULL 
) const
virtualinherited

ν1ν2 Iν dν (or jν)

Compute the integral of emission() from ν1 to ν2. 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.

virtual void Gyoto::Astrobj::Generic::integrateEmission ( double *  I,
double const *  boundaries,
size_t const *  chaninds,
size_t  nbnu,
double  dsem,
double *  cph,
double *  co 
) const
virtualinherited

ν1ν2 Iν dν (or jν)

Like double integrateEmission(double nu1, double nu2, double dsem, double c_ph[8], double c_obj[8]) const for each Spectrometer channel.

virtual double Gyoto::Astrobj::Standard::operator() ( double const  coord[4])
pure virtual

Function defining the object interior.

A potential, distance, or whatever function such that operator()(double const coord[4]) < Standard::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, Gyoto::Astrobj::Torus, Gyoto::Astrobj::StarTrace, and Gyoto::Astrobj::PolishDoughnut.

void Gyoto::Astrobj::Generic::opticallyThin ( int  flag)
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.

Parameters
flag1 if optically thin, 0 if optically thick.
int Gyoto::Astrobj::Generic::opticallyThin ( ) const
inherited

Query whether object is optically thin.

See opticallyThin(int flag).

virtual void Gyoto::Astrobj::Generic::processHitQuantities ( Photon ph,
double *  coord_ph_hit,
double *  coord_obj_hit,
double  dt,
Astrobj::Properties data 
) const
virtualinherited

Fills Astrobj::Properties.

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::transmit(), only if data==NULL.

You can overload it for your Astrobj. The generic implementation calls emission(), integrateEmission() and transmission() below.

Reimplemented in Gyoto::Astrobj::UniformSphere, and Gyoto::Astrobj::PageThorneDisk.

virtual double Gyoto::Astrobj::Generic::rMax ( )
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 rmax(). If rmax has been used to set rmax_, rMax() must not recompute it.

Returns
rmax_ in geometrical units

Reimplemented in Gyoto::Astrobj::Star, and Gyoto::Astrobj::Torus.

virtual double Gyoto::Astrobj::Generic::rMax ( std::string  unit)
virtualinherited

Get rmax_ is specified unit.

Call rMax() and convert result to unit.

Parameters
unitstring
Returns
double rmax converted to unit
virtual void Gyoto::Astrobj::Generic::rMax ( double  val)
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.

Parameters
valnew rmax_ in geometrical units.
virtual void Gyoto::Astrobj::Generic::rMax ( double  val,
std::string  unit 
)
virtualinherited

Set maximal distance from center of coordinate system.

Call Generic::rMax(double val) after converting val from unit to geometrical units.

Parameters
valrmax_ expressed in unit "unit";
unitstring...
virtual int Gyoto::Astrobj::Standard::setParameter ( std::string  name,
std::string  content,
std::string  unit = "" 
)
virtual

Set parameter by name.

Assume MyKind is a subclass of Astrobj::Generic which has two members (a string StringMember and a double DoubleMember):

int MyKind::setParameter(std::string name,
std::string content,
std::string unit) {
if (name=="StringMember") setStringMember(content);
else if (name=="DoubleMember") setDoubleMember(atof(content.c_str()),
unit);
else return Generic::setParameter(name, content, unit);
return 0;
}

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().

Parameters
nameXML name of the parameter
contentstring representation of the value
unitstring representation of the unit
Returns
0 if this parameter is known, 1 if it is not.

Reimplemented from Gyoto::Astrobj::Generic.

Reimplemented in Gyoto::Astrobj::UniformSphere, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::Star, Gyoto::Astrobj::Torus, Gyoto::Astrobj::StarTrace, and Gyoto::Astrobj::FixedStar.

virtual void Gyoto::Astrobj::Generic::setParameters ( FactoryMessenger *  fmp)
virtualinherited

Main loop in Subcontractor_t function.

The Subcontractor_t function for each Astrobj kind should look somewhat like this (templated as Gyoto::Astrobj::Subcontractor<MyKind>):

SmartPointer<Astrobj::Generic>
Gyoto::Astrobj::MyKind::Subcontractor(FactoryMessenger* fmp) {
SmartPointer<MyKind> ao = new MyKind();
ao -> setParameters(fmp);
return ao;
}

Each object kind should implement setParameter(string name, string content, string unit) 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::UniformSphere, Gyoto::Astrobj::Star, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::Complex.

virtual double Gyoto::Astrobj::Generic::transmission ( double  nuem,
double  dsem,
double  coord[8] 
) const
virtualinherited

Transmission: exp( αν * 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.

Parameters
nuemfrequency in the fluid's frame
coordPhoton coordinate
dsemgeometrical length in geometrical units

Reimplemented in Gyoto::Astrobj::PatternDisk, Gyoto::Astrobj::PolishDoughnut, Gyoto::Astrobj::Torus, and Gyoto::Astrobj::DynamicalDisk3D.

virtual void Gyoto::Astrobj::Generic::unsetRmax ( )
virtualinherited

Set rmax_set_ to 0.

rmax() will then be free to recompute rmax_. Astrobjs which cache rmax_ may need to update it when unrmax() is called.

Reimplemented in Gyoto::Astrobj::Star.

Member Data Documentation

std::string Gyoto::Astrobj::Generic::kind_
protectedinherited

Kind of object (e.g. "Star"...)

The kind should match the name of the class, e.g. "Star" for a Gyoto::Star.

double Gyoto::Astrobj::Generic::rmax_
protectedinherited

Maximum distance to the center of the coordinate system [geometrical units].

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 rMax() is called. External classes (Photons in particular) must use rMax() to access this information.

rmax_set_==1 means that rmax_ was set using rMax() or the constructor. In this case, rMax() must always return this value, not recompute it.

rmax_ is in geometrical units.

int Gyoto::Astrobj::Generic::rmax_set_
protectedinherited

Never recompute rmax: it was externally set.

rmax_set_==1 means that rmax_ was set using rMax(double r) or the constructor. In this case, rMax() must always return this value, not recompute it.

Use unsetRmax() to reset rmax_set_ to 0.


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