Gyoto::Worldline Class Reference

Timelike or null geodesics. More...

#include <GyotoWorldline.h>

Inheritance diagram for Gyoto::Worldline:
Gyoto::Hook::Listener Gyoto::Astrobj::EquatorialHotSpot Gyoto::Astrobj::Star Gyoto::Photon Gyoto::Astrobj::InflateStar Gyoto::Astrobj::StarTrace Gyoto::Photon::Refined

List of all members.

Classes

class  IntegState

Public Member Functions

 Worldline ()
 Default constructor.
 Worldline (const Worldline &)
 Copy constructor.
 Worldline (Worldline *orig, size_t i0, int dir, double step_max)
 Refine constructor.
virtual ~Worldline ()
 Destructor.
size_t getImin () const
 Get imin_.
size_t getImax () const
 Get imax_.
size_t getI0 () const
 Get i0_.
virtual double getMass () const =0
 Get mass of particule.
void metric (SmartPointer< Metric::Generic >)
 Set metric Smartpointer.
SmartPointer< Metric::Genericmetric () const
 Get metric.
void initCoord (std::vector< double > const &)
std::vector< double > initCoord () const
virtual void setInitCoord (const double coord[8], int dir=0)
 Set Initial coordinate.
virtual void setInitCoord (double const pos[4], double const vel[3], int dir=0)
 Set initial coordinate.
virtual void setPosition (double const pos[4])
 Set initial 4-position.
virtual void setVelocity (double const vel[3])
 Set initial 3-velocity.
void reset ()
 Forget integration, keeping initial contition.
void reInit ()
 Reset and recompute particle properties.
virtual std::string className () const
 "Worldline"
virtual std::string className_l () const
 "worldline"
void integrator (std::string const &type)
 Set the integrator.
std::string integrator () const
 Describe the integrator used by state_.
double deltaMin () const
 Get delta_min_.
void deltaMin (double h1)
 Set delta_min_.
double deltaMax () const
 Get delta_max_.
void absTol (double)
 Set abstol_.
double absTol () const
 Get abstol_.
void relTol (double)
 Set reltol_.
double relTol () const
 Get reltol_.
virtual double deltaMax (double const pos[8], double delta_max_external) const
void deltaMax (double h1)
double deltaMaxOverR () const
 Get delta_max_over_r_.
void deltaMaxOverR (double t)
 Set delta_max_over_r_.
void delta (const double delta)
 Assignment to another Worldline.
void delta (double, const std::string &unit)
 Set delta_ in specified units.
double delta () const
 Get delta_.
double delta (const std::string &unit) const
 Get delta_ in specified units.
double tMin () const
 Get tmin_.
double tMin (const std::string &unit) const
 Get tmin_ in specified unit.
void tMin (double tlim)
 Set tmin_.
void tMin (double, const std::string &unit)
 Set tmin_ in specified unit.
void adaptive (bool mode)
 Set adaptive_.
bool adaptive () const
 Get adaptive_.
void secondary (bool sec)
 Set secondary_.
bool secondary () const
 Get secondary_.
void maxiter (size_t miter)
 Set maxiter_.
size_t maxiter () const
 Get maxiter_.
double const * getCst () const
 Returns the worldline's cst of motion (if any).
void setCst (double const *cst, size_t const ncsts)
 Set Metric-specific constants of motion.
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 getCartesianPos (size_t index, double dest[4]) const
 Get Cartesian expression of 4-position at index.
virtual void xStore (size_t ind, double const coord[8])
 Store coord at index ind.
virtual void xFill (double tlim)
 Fill x0, x1... by integrating the Worldline from previously set inittial condition to time tlim.
size_t get_nelements () const
 Get number of computed dates.
void get_t (double *dest) const
 Get computed dates.
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)
 Get the 6 Cartesian coordinates for specific dates.
void get_xyz (double *x, double *y, double *z) const
 Get 3-position in cartesian coordinates for computed dates.
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)
 Get 8-coordinates for specific dates.
void getCoord (double *x0, double *x1, double *x2, double *x3) const
 Get all computed positions.
void checkPhiTheta (double coord[8]) const
 Bring in [0,] and in [0,2].
void getSkyPos (SmartPointer< Screen > screen, double *dalpha, double *ddellta, double *dD) const
 Get computed positions in sky coordinates.
void get_dot (double *x0dot, double *x1dot, double *x2dot, double *x3dot) const
 Get computed 4-velocities.
void get_prime (double *x1prime, double *x2prime, double *x3prime) const
 Get computed 3-velocities.
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.

Public Attributes

int stopcond
 Whether and why integration is finished.

Protected Member Functions

virtual void xAllocate ()
 Allocate x0, x1 etc. with default size.
virtual void xAllocate (size_t size)
 Allocate x0, x1 etc. with a specified size.
virtual size_t xExpand (int dir)
 Expand x0, x1 etc... to hold more elements.
virtual void xExpand (double *&x, int dir)
 Expand one array to hold more elements.
virtual void tell (Gyoto::Hook::Teller *)
 This is how a Teller tells.

Protected Attributes

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_
 or y
double * x3_
 or z
double * x0dot_
 tdot or Tdot
double * x1dot_
 rdot or xdot
double * x2dot_
 dot or ydot
double * x3dot_
 dot 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.
bool adaptive_
 Whether integration should use adaptive delta.
bool secondary_
 Experimental: choose 0 to compute only primary image.
double delta_
 Initial integrating step.
double tmin_
 Time limit for the integration (geometrical units).
double * cst_
 Worldline's csts of motion (if any).
size_t cst_n_
 Number of constants of motion.
int wait_pos_
 Hack in setParameters().
double * init_vel_
 Hack in setParameters().
size_t maxiter_
 Maximum number of iterations when integrating.
double delta_min_
 Minimum integration step for the adaptive integrator.
double delta_max_
 Maximum integration step for the adaptive integrator.
double delta_max_over_r_
 Numerical tuning parameter.
double abstol_
 Absolute tolerance of the integrator.
double reltol_
 Absolute tolerance of the integrator.
SmartPointer
< Worldline::IntegState::Generic
state_
 An object to hold the integration state.

Friends

class Gyoto::Hook::Teller

Detailed Description

Timelike or null geodesics.

Their are two derived classes: Photon and Star. A Worldline can be integrated from an initial condition either backward or forward in time using xFill() (Photon::hit() also integrates the Worldline). Member state_ holds the integration state as well as an integrator. There are several kinds of integration states, that derive from IntegState::Generic.

The coordinates of the Worldline are stored in x0_, x1_, x2_, x3_, x0dot_, x1dot_, x2dot_ ans x3dot_. Those arrays are extended as needed using xExpand(). These coordinates can be retrieved using get_t(), get_xyz(), getCartesian(), getCoord() etc.

Worldline does not derive from Object, and does not instantiate a Property list. This is because this would lead to multiple inheritance of the Object base in derived classes. Instead, GyotoWorldline.h provides a few macros that can be used to include the Worldline properties in a derived classe's Property list:


Constructor & Destructor Documentation

Gyoto::Worldline::Worldline ( Worldline orig,
size_t  i0,
int  dir,
double  step_max 
)

Refine constructor.

Meant to instantiate a copy of orig with a smaller step to refine integration, for instance for more accurate radiative transfer integration.

See Photon::Photon(Photon* orig, size_t i0, int dir, double step_max) and Photon::Refined.

Parameters:
orig Worldline to refine
i0 Index of coordinate in orig to take as initial condition
dir Direction of integration
step_max Maximum integration step

Member Function Documentation

void Gyoto::Worldline::checkPhiTheta ( double  coord[8]  )  const

Bring in [0,] and in [0,2].

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".

void Gyoto::Worldline::delta ( const double  delta  ) 

Assignment to another Worldline.

Set delta_

void Gyoto::Worldline::deltaMax ( double  h1  ) 

Set delta_max_

virtual double Gyoto::Worldline::deltaMax ( double const   pos[8],
double  delta_max_external 
) const [virtual]

Get delta max at a given position

Parameters:
[in] pos 4-position
[in] delta_max_external external constraint on delta_max
Returns:
the smallest value between delta_max_, delta_max_external, and R*delta_max_over_r_ where R is pos[1] in spherical coordinates and max(x1, x2, x3) in Cartesian coordinates.
void Gyoto::Worldline::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 
)

Get the 6 Cartesian coordinates for specific dates.

The 6 coordinates (x, y, z, dx/dt, dy/dt, dz/dt) will be computed using the integrator and interpolated if necessary, so they will be as accurate as possible. Transforming to Cartesian coordinates is not necessarily meaningful.

Parameters:
[in] dates List of dates for which the coordinates are to be computed;
[in] n_dates Number of dates to compute ;
[out] x,y,z,xprime,yprime,zprime Arrays in which to store the result. These pointer may be set to NULL to retrieve only part of the information. Else, they must be pre-allocated.

Reimplemented in Gyoto::Astrobj::Star.

void Gyoto::Worldline::getCoord ( double *  x0,
double *  x1,
double *  x2,
double *  x3 
) const

Get all computed positions.

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

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 
)

Get 8-coordinates for specific 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 ;
x1dest,x2dest,x3dest,x0dot,x1dot,x2dot,x3dot 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.
double const* Gyoto::Worldline::getCst (  )  const

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

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

void Gyoto::Worldline::integrator ( std::string const &  type  ) 

Set the integrator.

Initialize state_ to use the required integrator.

Parameters:
[in] type Either "Legacy" or (if GYOTO_HAVE_BOOST_INTEGRATORS) one of "runge_kutta_cash_karp54", "runge_kutta_fehlberg78", "runge_kutta_dopri5", "runge_kutta_cash_karp54_classic"
void Gyoto::Worldline::setCst ( double const *  cst,
size_t const   ncsts 
)

Set Metric-specific constants of motion.

The will (re)allocate Worldline::cst_, copy cst into it, and set Worldline::cst_n_.

virtual void Gyoto::Worldline::setInitCoord ( double const   pos[4],
double const   vel[3],
int  dir = 0 
) [virtual]

Set initial coordinate.

Parameters:
pos initial 4-position
vel initial 3-velocity
dir direction of integration
virtual void Gyoto::Worldline::setInitCoord ( const double  coord[8],
int  dir = 0 
) [virtual]

Set Initial coordinate.

Set imin_=imax_=i0_, and x_[i0_]=coord[].

If dir==1, i0_ is set to 0. If dir==-1, i0_ is set to x_size_-1.

If dir==0 and the Worldine has never been computed (i0_==0, imin_==1 and imax_==0), then dir defaults to 1 for a massive particle and -1 for a massless particle.

If dir==0 and the Worldine has already been computed, i0_ is not changed.

Parameters:
coord new initial coordinates
dir direction of integration. 1 for forward integration, -1 for backards integration, 0 for unknown or both.

Reimplemented in Gyoto::Astrobj::StarTrace.

void Gyoto::Worldline::setInitialCondition ( SmartPointer< Metric::Generic gg,
const double  coord[8],
const int  dir 
)

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

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;
dir direction: 1 for future, -1 for past.
virtual void Gyoto::Worldline::tell ( Gyoto::Hook::Teller msg  )  [protected, virtual]

This is how a Teller tells.

A teller will basically call listener->tell(this).

Parameters:
msg Teller* the Teller who is telling... Useful if the Listener listens to several Tellers.

Reimplemented from Gyoto::Hook::Listener.

virtual void Gyoto::Worldline::xAllocate ( size_t  size  )  [protected, virtual]

Allocate x0, x1 etc. with a specified size.

Parameters:
size : number of cells in each array x0, x1 etc.

Reimplemented in Gyoto::Astrobj::StarTrace.

virtual void Gyoto::Worldline::xAllocate (  )  [protected, virtual]

Allocate x0, x1 etc. with default size.

The default size is GYOTO_DEFAULT_X_SIZE

virtual void Gyoto::Worldline::xExpand ( double *&  x,
int  dir 
) [protected, virtual]

Expand one array to hold more elements.

If you need to expand more arrays than x0_ ... x3_ and the dots, call this on your array before calling xExpand(int dir).

Parameters:
inout] x array to expand
[in] dir 
virtual size_t Gyoto::Worldline::xExpand ( int  dir  )  [protected, virtual]

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

Reimplemented in Gyoto::Astrobj::StarTrace.


Member Data Documentation

double Gyoto::Worldline::abstol_ [protected]

Absolute tolerance of the integrator.

Used by the adaptive integrators implemented in IntegState::Boost. Refer to the boost::numeric::odeint documentation for more details.

double Gyoto::Worldline::delta_ [protected]

Initial integrating step.

Default: GYOTO_DEFAULT_DELTA

double Gyoto::Worldline::delta_max_ [protected]

Maximum integration step for the adaptive integrator.

The default (GYOTO_DEFAULT_DELTA_MAX) is usually fine.

For IntegState::Legacy, set it in the Metric instead!

Numerical tuning parameter.

For IntegState::Legacy, set it in the Metric instead!

Ensure that delta (the numerical integration step) is never larger than a fraction of the distance between the current location and the center of the coordinate system.

The default (GYOTO_DEFAULT_DELTA_MAX_OVER_R) is usually fine.

double Gyoto::Worldline::delta_min_ [protected]

Minimum integration step for the adaptive integrator.

The default (GYOTO_DEFAULT_DELTA_MIN) is usually fine.

For IntegState::Legacy, set it in the Metric instead!

double Gyoto::Worldline::reltol_ [protected]

Absolute tolerance of the integrator.

Used by the adaptive integrators implemented in IntegState::Boost. Refer to the boost::numeric::odeint documentation for more details.

bool Gyoto::Worldline::secondary_ [protected]

Experimental: choose 0 to compute only primary image.

This feature is in development.

double Gyoto::Worldline::tmin_ [protected]

Time limit for the integration (geometrical units).

Computation does not go back before tmin_. Default is -DBL_MAX. tmin_ is always expressed in geometrical units, it is essentially a tuning parameter for the ray-tracing process. tmin_ should be chosen to always be longer than the distance between the screen and the object.

Reimplemented in Gyoto::Astrobj::StarTrace.


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

Generated on 22 Jul 2017 for Gyoto by  doxygen 1.6.1