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Gyoto::Metric::Generic Class Referenceabstract

Base class for metrics. More...

#include <GyotoMetric.h>

Inheritance diagram for Gyoto::Metric::Generic:
Gyoto::SmartPointee Gyoto::Hook::Teller Gyoto::Metric::KerrBL Gyoto::Metric::KerrKS Gyoto::Metric::RotStar3_1

Public Member Functions

const std::string getKind () const
 Get kind_.
 
void setKind (const std::string)
 Set kind_.
 
int getRefCount ()
 
 Generic (const int coordkind)
 Constructor setting Generic::coordkind_.
 
 Generic (const double mass, const int coordkind)
 Constructor setting Generic::mass_ and Generic::coordkind_.
 
virtual ~Generic ()
 Destructor.
 
virtual Genericclone () const
 Virtual copy constructor.
 
void setMass (const double)
 Set mass used in unitLength()
 
void setMass (const double, const std::string &unit)
 Set mass used in unitLength()
 
int getCoordKind () const
 Get coordinate kind.
 
void setCoordKind (int coordkind)
 Set coordinate kind.
 
double getMass () const
 Get mass used in unitLength()
 
double getMass (const std::string &unit) const
 Get mass used in unitLength()
 
double unitLength () const
 M * G / c^2, M is in kg, unitLength in meters. More...
 
double unitLength (const std::string &unit) const
 unitLength expressed in specified unit
 
virtual void cartesianVelocity (double const coord[8], double vel[3])
 Compute xprime, yprime and zprime from 8-coordinates.
 
virtual double SysPrimeToTdot (const double coord[4], const double v[3]) const
 Compute tdot as a function of dr/dt, dtheta/dt and dphi/dt. Everything is in geometrical units. More...
 
virtual void circularVelocity (double const pos[4], double vel[4], double dir=1.) const
 Yield circular valocity at a given position (projected on equatorial plane). More...
 
virtual void nullifyCoord (double coord[8]) const
 Set tdot (coord[4]) such that coord is light-like. Everything is in geometrical units. More...
 
virtual void nullifyCoord (double coord[8], double &tdot2) const
 Set tdot (coord[4]) such that coord is light-like and return other possible tdot. More...
 
virtual double ScalarProd (const double pos[4], const double u1[4], const double u2[4]) const
 Scalar product. More...
 
virtual double Norm3D (double *pos) const
 not clear
 
virtual void setParameter (std::string name, std::string content, std::string unit)
 Set parameter by name. More...
 
virtual void setParameters (Gyoto::FactoryMessenger *fmp)
 Main loop in Subcontractor_t function. More...
 
virtual void fillElement (FactoryMessenger *fmp)
 called from Factory More...
 
void processGenericParameters (Gyoto::FactoryMessenger *fmp)
 Process generic XML parameters.
 
virtual double gmunu (const double *x, int mu, int nu) const =0
 Metric coefficients. More...
 
virtual double christoffel (const double coord[8], const int alpha, const int mu, const int nu) const =0
 Chistoffel symbol. More...
 
virtual int myrk4 (Worldline *line, const double coord[8], double h, double res[8]) const
 RK4 integrator.
 
virtual int myrk4_adaptive (Gyoto::Worldline *line, const double coord[8], double lastnorm, double normref, double coordnew[8], double h0, double &h1) const
 RK4 integrator with adaptive step.
 
virtual int isStopCondition (double const *const coord) const
 Check whether integration should stop. More...
 
virtual int diff (const double y[8], double res[8]) const
 F function such as dy/dtau=F(y,cst)
 
virtual void setParticleProperties (Gyoto::Worldline *line, const double *coord) const
 Set Metric-specific constants of motion. Used e.g. in KerrBL.
 
virtual void hook (Listener *listener)
 Start listening. More...
 
virtual void unhook (Listener *listener)
 Stop listening. More...
 

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.
 
virtual void tellListeners ()
 Call tell() on each hooked Listener. More...
 

Private Attributes

std::string kind_
 Metric kind name (e.g. "KerrBL")
 
double mass_
 Mass yielding geometrical unit (in kg).
 
int coordkind_
 Kind of coordinates (cartesian-like, spherical-like, unspecified)
 

Friends

class Gyoto::SmartPointer< Gyoto::Metric::Generic >
 

Detailed Description

Base class for metrics.

Example: class Gyoto::Metric::KerrBL

See Gyoto::Metric for an introduction.

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().

Member Function Documentation

virtual double Gyoto::Metric::Generic::christoffel ( const double  coord[8],
const int  alpha,
const int  mu,
const int  nu 
) const
pure virtual

Chistoffel symbol.

Value of Christoffel symbol Γαμν at point (x1, x2, x3).

Implemented in Gyoto::Metric::RotStar3_1, Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual void Gyoto::Metric::Generic::circularVelocity ( double const  pos[4],
double  vel[4],
double  dir = 1. 
) const
virtual

Yield circular valocity at a given position (projected on equatorial plane).

Parameters
posinput: position,
veloutput: velocity,
dir1 for corotating, -1 for counterrotating.

Reimplemented in Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual void Gyoto::Metric::Generic::fillElement ( FactoryMessenger fmp)
virtual

called from Factory

Metrics implementations should impement fillElement to save their parameters to XML and call the Metric::fillElement(fmp) for the shared properties

Reimplemented in Gyoto::Metric::RotStar3_1, Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual double Gyoto::Metric::Generic::gmunu ( const double *  x,
int  mu,
int  nu 
) const
pure virtual

Metric coefficients.

Parameters
x4-position at which to compute the coefficient;
mu1st index of coefficient, 0≤μ≤3;
nu2nd index of coefficient, 0≤ν≤3;
Returns
Metric coefficient gμ,ν at point x

Implemented in Gyoto::Metric::RotStar3_1, Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual void Gyoto::Hook::Teller::hook ( Listener listener)
virtualinherited

Start listening.

Use from a Hook::Listener object method:

teller->hook(this)

where "this" is a Listener and "teller" is a Teller.

Use unhook() later to stop listening to a given Teller.

Parameters
listenerpointer to the new listener
virtual int Gyoto::Metric::Generic::isStopCondition ( double const *const  coord) const
virtual

Check whether integration should stop.

The integrating loop will ask this the Metric through this method whether or not it is happy to conitnue the integration. Typically, the Metric should answer 0 when everything is fine, 1 when too close to the event horizon, inside the BH...

Parameters
coord8-coordinate vector to check.

Reimplemented in Gyoto::Metric::KerrKS.

virtual void Gyoto::Metric::Generic::nullifyCoord ( double  coord[8]) const
virtual

Set tdot (coord[4]) such that coord is light-like. Everything is in geometrical units.

Set coord[4] so that the 4-velocity coord[4:7] is lightlike, i.e. of norm 0. There may be up to two solutions. coord[4] is set to the hightest. The lowest can be retrieved using nullifyCoord(double coord[8], double& tdot2) const. Everything is expressed in geometrical units.

Parameters
[in,out]coord8-position, coord[4] will be set according to the other elements;

Reimplemented in Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual void Gyoto::Metric::Generic::nullifyCoord ( double  coord[8],
double &  tdot2 
) const
virtual

Set tdot (coord[4]) such that coord is light-like and return other possible tdot.

Set coord[4] so that the 4-velocity coord[4:7] is lightlike, i.e. of norm 0. There may be up to two solutions. coord[4] is set to the hightest. The lowest can be retrieved in tdot2. Everything is expressed in geometrical units.

Parameters
[in,out]coord8-position, coord[4] will be set according to the other elements;
[out]tdot2will be set to the smallest solution

Reimplemented in Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual double Gyoto::Metric::Generic::ScalarProd ( const double  pos[4],
const double  u1[4],
const double  u2[4] 
) const
virtual

Scalar product.

Compute the scalarproduct of the two quadrivectors u1 and u2 in this Metric, at point pos expressed in coordinate system sys.

Parameters
pos4-position;
u11st quadrivector;
u22nd quadrivector;
Returns
u1*u2

Reimplemented in Gyoto::Metric::RotStar3_1, and Gyoto::Metric::KerrBL.

virtual void Gyoto::Metric::Generic::setParameter ( std::string  name,
std::string  content,
std::string  unit 
)
virtual

Set parameter by name.

Assume MyKind is a subclass of Metric::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") setDoubleMemeber(atof(content.c_str()), unit);
else return Generic::setParameter(name, content, unit);
return 0;
}

If MyKind is not a direct subclass of Generic, 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 in Gyoto::Metric::RotStar3_1, Gyoto::Metric::KerrBL, and Gyoto::Metric::KerrKS.

virtual void Gyoto::Metric::Generic::setParameters ( Gyoto::FactoryMessenger fmp)
virtual

Main loop in Subcontractor_t function.

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

SmartPointer<Metric::Generic>
Gyoto::Metric::MyKind::Subcontractor(FactoryMessenger* fmp) {
SmartPointer<MyKind> gg = new MyKind();
gg -> setParameters(fmp);
return gg;
}
 Each metric kind should implement setParameter(string name,
 string content, string unit) to interpret the individual XML
 elements. setParameters() can be overloaded in case the specific
 Metric class needs low level access to the FactoryMessenger. See
 Gyoto::Astrobj::UniformSphere::setParameters().

Reimplemented in Gyoto::Metric::RotStar3_1.

virtual double Gyoto::Metric::Generic::SysPrimeToTdot ( const double  coord[4],
const double  v[3] 
) const
virtual

Compute tdot as a function of dr/dt, dtheta/dt and dphi/dt. Everything is in geometrical units.

Parameters
coord4-position (geometrical units);
v3-velocity dx1/dx0, dx2/dx0, dx3/dx0;
Returns
tdot = dx0/dtau.
virtual void Gyoto::Hook::Teller::tellListeners ( )
protectedvirtualinherited

Call tell() on each hooked Listener.

Whenever a Teller mutates, it should warn any Listener hooked to it using tellListeners().

virtual void Gyoto::Hook::Teller::unhook ( Listener listener)
virtualinherited

Stop listening.

Use from a Hook::Listener object method:

teller->unhook(this)

where "this" is a Listener, "teller" is a Teller, and "this" has called teller->hook(this) previously.

Parameters
listenerpointer to the listener
double Gyoto::Metric::Generic::unitLength ( ) const

M * G / c^2, M is in kg, unitLength in meters.

Metrics implementations are free to express lengths and distances in whatever unit they see fit (presumably most often geometrical units). This function returns this unit in SI (meters).


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