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Gyoto::Astrobj::Star Class Reference

Mass-less, spherical object following a timelike geodesic. More...

#include <GyotoStar.h>

Inheritance diagram for Gyoto::Astrobj::Star:
Gyoto::Astrobj::UniformSphere Gyoto::Worldline Gyoto::Astrobj::Standard Gyoto::Astrobj::Generic Gyoto::Functor::Double_constDoubleArray Gyoto::SmartPointee

Public Member Functions

 Star (SmartPointer< Metric::Generic > gg, double radius, double pos[4], double v[3])
 Standard constructor.
 Star ()
 Default constructor.
 Star (const Star &orig)
 Copy constructor.
virtual Starclone () const
 "Virtual" copy constructor
virtual ~Star ()
 Destructor.
virtual std::string className () const
 "Star"
virtual std::string className_l () const
 "star"
virtual void setMetric (SmartPointer< Metric::Generic >)
 Set metric Smartpointer.
virtual SmartPointer
< Metric::Generic
getMetric () const
 Get metric.
virtual double getMass () const
 Return 1.
virtual double getRmax ()
 Get maximal distance from center of coordinate system.
virtual void unsetRmax ()
 Set rmax_set_ to 0.
void setInitialCondition (double coord[8])
 Same as Worldline::setInitialCondition(gg, coord, sys,1)
virtual void setInitCoord (double pos[4], double vel[3], int dir=1)
virtual void setPosition (double pos[4])
virtual void setVelocity (double vel[3])
virtual int setParameter (std::string name, std::string content)
 Called from setParameters()
virtual void setParameters (FactoryMessenger *fmp)
virtual void fillElement (FactoryMessenger *fmp) const
 called from Factory
virtual void getCartesian (double const *const dates, size_t const n_dates, double *const x, double *const y, double *const z, double *const xprime=NULL, double *const yprime=NULL, double *const zprime=NULL)
 Yield the Cartesian coordinates of the center of the sphere.
virtual void getVelocity (double const pos[4], double vel[4])
 Yield velocity of the center of the sphere.
virtual void setSpectrum (SmartPointer< Spectrum::Generic >)
 Set spectrum_.
virtual SmartPointer
< Spectrum::Generic
getSpectrum () const
 Get spectrum_.
virtual void setOpacity (SmartPointer< Spectrum::Generic >)
 Set opacity_.
virtual SmartPointer
< Spectrum::Generic
getOpacity () const
 Get opacity_.
double getRadius () const
 Get radius_.
void setRadius (double)
 Set radius_.
virtual double operator() (double const coord[4])
 Square distance to the center of the sphere.
virtual double operator() (double const data[])=0
virtual double transmission (double nuem, double dsem, double coord[8]) const
 Transmission: exp( {} * dsem )
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 giveDelta (double coord[8])
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.
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 processHitQuantities (Photon *ph, double *coord_ph_hit, double *coord_obj_hit, double dt, Astrobj::Properties *data) const
void checkPhiTheta (double coord[8]) const
int getImin () const
int getImax () const
int getI0 () const
void setInitCoord (const double coord[8], int dir=0)
 Set Initial coordinate.
void reset ()
 Forget integration, keeping initial contition.
void setDelta (const double delta)
 Set delta.
double getTlim () const
 Get tlim value.
void setTlim (double tlim)
 Set tlim to a given value.
double const * getCst () const
 Returns the worldline's cst of motion (if any)
void setCst (double const *cst, size_t const ncsts)
void setInitialCondition (SmartPointer< Metric::Generic > gg, const double coord[8], const int dir)
 Set or re-set the initial condition prior to integration.
void getInitialCoord (double dest[8]) const
 get initial coordinate
void getCoord (size_t index, double dest[8]) const
 get coordinates corresponding to index
void getCoord (double const *const dates, size_t const n_dates, double *const x1dest, double *const x2dest, double *const x3dest, double *const x0dot=NULL, double *const x1dot=NULL, double *const x2dot=NULL, double *const x3dot=NULL)
void getCoord (double *x0, double *x1, double *x2, double *x3) const
void getCartesianPos (size_t index, double dest[4]) const
 get Cartesian expression of 4-position at index.
void xFill (double tlim)
 Fill x0, x1... by integrating the Worldline from previously set inittial condition to time tlim.
int get_nelements () const
void get_t (double *dest) const
void get_xyz (double *x, double *y, double *z) const
void getSkyPos (SmartPointer< Screen > screen, double *dalpha, double *ddellta, double *dD) const
void get_dot (double *x0dot, double *x1dot, double *x2dot, double *x3dot) const
void get_prime (double *x1prime, double *x2prime, double *x3prime) const
void save_txyz (char *fichierxyz) const
 Save in a file.
void save_txyz (char *const filename, double const t1, double const mass_sun, double const distance_kpc, std::string const unit, SmartPointer< Screen > sc=NULL)
 Save, converted.

Protected Types

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

Protected Member Functions

virtual double emission (double nu_em, double dsem, double cp[8], double co[8]=NULL) const
 Emission is determined by spectrum_ and opacity_.
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 *) const
 Transmission is determined by opacity_.
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.
void xAllocate ()
 Allocate x0, x1 etc. with default size.
void xAllocate (size_t size)
 Allocate x0, x1 etc. with a specified size.
size_t xExpand (int dir)
 Expand x0, x1 etc... to hold more elements.

Protected Attributes

double radius_
 sphere radius
SmartPointer< Spectrum::Genericspectrum_
 sphere emission law
SmartPointer< Spectrum::Genericopacity_
 if optically thin, opacity law
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
SmartPointer
< Gyoto::Metric::Generic
metric_
 The Gyoto::Metric in this part of the universe.
double * x0_
 t or T
double * x1_
 r or x
double * x2_
 theta or y
double * x3_
 phi or z
double * x0dot_
 tdot or Tdot
double * x1dot_
 rdot or xdot
double * x2dot_
 thetadot or ydot
double * x3dot_
 phidot or zdot
size_t x_size_
 Size of x0, x1... arrays.
size_t imin_
 Minimum index for which x0, x1... have been computed.
size_t i0_
 Index of initial condition in array.
size_t imax_
 Maximum index for which x0, x1... have been computed.
double delta_
 Initial integrating step ; defaults to 0.01.
double tlim_
 Minimum time for integration, stop integration if t<tlim ; defaults to 0.
double * cst_
 Worldline's csts of motion (if any)
size_t cst_n_
 Number of constants of motion.

Private Attributes

int wait_pos_
 Hack in setParameters()
double * init_vel_
 Hack in setParameters()

Friends

class Gyoto::SmartPointer< Gyoto::Astrobj::Star >

Detailed Description

Mass-less, spherical object following a timelike geodesic.

Gyoto can compute the Star's orbit in a Gyoto::Metric and perform ray-tracing on this target. The XML description of a Star looks like:

<Astrobj kind = "Star">
<Metric kind = "KerrBL">
<Spin> 0. </Spin>
</Metric>
<Radius> 2. </Radius>
<Velocity> 0. 0. 0.037037 </Velocity>
<Position> 600. 9. 1.5707999999999999741 0 </Position>
<Spectrum kind="BlackBody">
<Temperature> 6000 </Temperature>
</Spectrum>
<Opacity kind="PowerLaw">
<Exponent> 0 </Exponent>
<Constant> 0.1 </Constant>
</Opacity>
<OpticallyThin/>
</Astrobj>

The Metric element can be of any kind. This Metric sets the coordinate system.

The Star is a coordinate sphere of radius Radius in solid motion.

Position sets the initial 4-coordinate of the centre of the sphere. Velocity contains its initial 3-velocity (the time derivatives of the 3 space coordinates).

Like many Astrobj::Generic impementations, a Star can be OpticallyThin or OpticallyThick.

Spectrum and Opacity (if OpticallyThin) are the descriptions of two Gyoto::Spectrum::Generic sub-classes.

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::Star::Star ( SmartPointer< Metric::Generic gg,
double  radius,
double  pos[4],
double  v[3] 
)

Standard constructor.

Create Star object and set initial condition.

Parameters
gg,:Gyoto::SmartPointer to the Gyoto::Metric in this part of the Universe
radiusstar radius
pos[4]initial position
v[3]initial velocity
Gyoto::Astrobj::Star::Star ( )

Default constructor.

Create Star object with undefined initial conditions. One needs to set the coordinate system, the metric, and the initial position and velocity before integrating the orbit. setInititialCondition() can be used for that.

Member Function Documentation

void Gyoto::Astrobj::Generic::checkPhiTheta ( double  coord[8]) const
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".

virtual Star* Gyoto::Astrobj::Star::clone ( ) const
virtual

"Virtual" copy constructor

 This method must be implemented by the various Astrobj::Generic
 subclasses in order to support cloning:
SmartPointer<Astrobj> deep_copy = original->clone();
 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); }

Implements Gyoto::Astrobj::Generic.

virtual void Gyoto::Astrobj::Star::getCartesian ( double const *const  dates,
size_t const  n_dates,
double *const  x,
double *const  y,
double *const  z,
double *const  xprime = NULL,
double *const  yprime = NULL,
double *const  zprime = NULL 
)
virtual

Yield the Cartesian coordinates of the center of the sphere.

If the coordinate system of the Metric object is spherical, use a trivial conversion.

Implements Gyoto::Astrobj::UniformSphere.

void Gyoto::Worldline::getCoord ( double const *const  dates,
size_t const  n_dates,
double *const  x1dest,
double *const  x2dest,
double *const  x3dest,
double *const  x0dot = NULL,
double *const  x1dot = NULL,
double *const  x2dot = NULL,
double *const  x3dot = NULL 
)
inherited

Get 8-coordinates for spcific dates. The coordinates will be computed using the integrator, so they will be as accurate as possible. Some heuristics are used to speed up the process and it is presumably faster to call this routine with a sorted list of dates. The line will be integrated further as required. An error will be thrown if it is not possible to reach a certain date.

Parameters
dates,:the list of dates for which the coordinates are to be computed;
n_dates,:the number of dates to compute ;
x*,:arrays in which to store the result. These pointer may be set to NULL to retrieve only part of the information. They must be pre-allocated.
void Gyoto::Worldline::getCoord ( double *  x0,
double *  x1,
double *  x2,
double *  x3 
) const
inherited

Get all the pre-computed 8 coordinates (e.g. thanks to a prior call to xFill()) of this worldline.

double const* Gyoto::Worldline::getCst ( ) const
inherited

Returns the worldline's cst of motion (if any)

Return pointer to array holding the previously set Metric-specific constants of motion

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

int Gyoto::Astrobj::Generic::getFlag_radtransf ( ) const
inherited

Query whether object is optically thin.

See setFlag_radtransf(int flag).

virtual double Gyoto::Astrobj::Star::getMass ( ) const
virtual

Return 1.

The mass of a Star is always 1. Stars do not perturb the metric. The only relevant point is that Stars are massive particules, their exact mass is of no importance.

Implements Gyoto::Worldline.

virtual double Gyoto::Astrobj::Star::getRmax ( )
virtual

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 from Gyoto::Astrobj::Generic.

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

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

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

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.

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

^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 from Gyoto::Astrobj::Generic.

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

void Gyoto::Worldline::setCst ( double const *  cst,
size_t const  ncsts 
)
inherited

Set Metric-specific constants of motion

void Gyoto::Astrobj::Generic::setFlag_radtransf ( 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
flag,:1 if optically thin, 0 if optically thick.
void Gyoto::Worldline::setInitialCondition ( SmartPointer< Metric::Generic gg,
const double  coord[8],
const int  dir 
)
inherited

Set or re-set the initial condition prior to integration.

Set initial condition for this Photon :

Parameters
gg: Gyoto::SmartPointer to the Gyoto::Metric in this universe;
coord: 8 element array containing the initial condition, i.e. the 4-position and the 4-velocity of the Photon at the receiving end;
sys: an integer stating in which coordinate system coord is given.
virtual int Gyoto::Astrobj::Star::setParameter ( std::string  name,
std::string  content 
)
virtual

Called from setParameters()

 Assume MyKind is a sublcass of Astrobj::Generic which has towo
 members (a string StringMember and a double DoubleMember):
int MyKind::setParameter(std::string name, std::string content) {
if (name=="StringMember") setStringMember(content);
else if (name=="DoubleMember") setDoubleMemeber(atof(content.c_str()));
else return Generic::setParameter(name, content);
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
Returns
0 if this parameter is known, 1 if it is not.

Reimplemented from Gyoto::Astrobj::UniformSphere.

virtual void Gyoto::Astrobj::Star::setParameters ( FactoryMessenger fmp)
virtual

This implementation of UniformSphere::setParameters() uses wait_pos_ and init_vel_ to make sure setVelocity() is called after setPosition().

Reimplemented from Gyoto::Astrobj::UniformSphere.

virtual void Gyoto::Astrobj::Generic::setRmax ( 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.

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

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

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

virtual void Gyoto::Astrobj::Star::unsetRmax ( )
virtual

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 from Gyoto::Astrobj::Generic.

void Gyoto::Worldline::xAllocate ( )
protectedinherited

Allocate x0, x1 etc. with default size.

The default size is GYOTO_DEFAULT_X_SIZE

void Gyoto::Worldline::xAllocate ( size_t  size)
protectedinherited

Allocate x0, x1 etc. with a specified size.

Parameters
size: number of cells in each array x0, x1 etc.
size_t Gyoto::Worldline::xExpand ( int  dir)
protectedinherited

Expand x0, x1 etc... to hold more elements.

Double the size of arrays x0, x1 etc. and copy old version of the array in the first half if dir =1 and in the second half if dir =-1.

Parameters
dir: 1 to expand after last element, -1 to expand before first element
Returns
ind : if dir=1, new index of old last element, if dir=-1, new index of old first element

Member Data Documentation

SmartPointer<Gyoto::Metric::Generic> Gyoto::Astrobj::Generic::gg_
protectedinherited

The Metric in this end of the Universe

const 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.

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.

int Gyoto::Astrobj::Generic::rmax_set_
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.


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