smile::COrbitRuntimeVelPerturber Class Reference

class for applying random perturbations on velocity during orbit integration, mimicking the effect of two-body relaxation. More...

#include <orbitan.h>

Inheritance diagram for smile::COrbitRuntimeVelPerturber:

Collaboration diagram for smile::COrbitRuntimeVelPerturber:

Public Member Functions
	COrbitRuntimeVelPerturber (const COrbit *_orbit, const CMassModel *_model, double _mult)
virtual FNCTYPE	FncType () const
	derived classes return their type
virtual STEPRESULT	Timestep (const double told, const double t, CPosVelPoint< double > *vars)
	Modifies the velocity by applying a random perturbation to it and records accumulated changes in E and L resulting from the perturbation. More...
virtual void	Finish ()
	fit pericenter distribution and compute fitting coefficients
virtual CBasicInformation *	getData () const
	returns the collected data as an instance of an information object
Public Member Functions inherited from smile::CBasicOrbitRuntimeFnc
	CBasicOrbitRuntimeFnc (const COrbit *_orbit)
	constructs instance and initializes some internal data
virtual	~CBasicOrbitRuntimeFnc ()
	destroys all necessary internal data

Private Attributes
const CMassModel *	model
	spherical mass model used to compute diffusion coefficients
const double	mult
	multiplier for the diffusion coefficients =(log Lambda)/N
double	Eorbitavg
	energy below which we use orbit-averaged dif.coefs instead of local ones
double	intTime
	total integration time
double	deltaE
double	deltaE2
double	deltaEcumul
	accumulated drift and diffusion coefficients in energy and its total change
double	deltaL
double	deltaL2
double	deltaLcumul
	accumulated drift and diffusion coefficients in angular momentum and its total change
double	avgCoefs [15]
	time-averaged coefficients DEE, DLL, DEL, DE, DL and their counterparts in spherical model

Additional Inherited Members
Public Types inherited from smile::CBasicOrbitRuntimeFnc
enum	FNCTYPE {   FT_TRAJ_ANALYSIS, FT_TRAJ_SAMPLE, FT_POINCARE, FT_PERICENTER,   FT_SCHW, FT_VEL_PERTURBER }
	lists all possible runtime functions More...
enum	STEPRESULT { SR_CONTINUE, SR_TERMINATE, SR_REINIT }
	result of processing of a timestep More...
Protected Attributes inherited from smile::CBasicOrbitRuntimeFnc
const COrbit *	orbit
	pointer to the orbit that is being integrated

Detailed Description

class for applying random perturbations on velocity during orbit integration, mimicking the effect of two-body relaxation.

The diffusion coefficients come in two varieties: local (position-dependent) coefficients for velocity, and orbit-averaged coefficients for energy and angular momentum. They are computed from a spherical mass model constructed as an approximation to the true (non-spherical) potential used in orbit integration itself. There is a free parameter that determines the scaling of these coefficients: its numerical value corresponds to , where N is the number of stars in the model galaxy, and log Lambda is the Coulomb logarithm (~log N).

Member Function Documentation

CBasicOrbitRuntimeFnc::STEPRESULT smile::COrbitRuntimeVelPerturber::Timestep ( const double  told, const double  t, CPosVelPoint< double > *  vars  )

virtual

Modifies the velocity by applying a random perturbation to it and records accumulated changes in E and L resulting from the perturbation.

Parameters

[in,out]	vars	is the current position and velocity of the orbit; the velocity is modified.
[in]	told	is the time at the beginning of timestep;
[in]	t	is the time at the end of timestep.

don't bother computing local coefs; just take orbit-averaged values and set new velocity

Implements smile::CBasicOrbitRuntimeFnc.

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

• orbitan.h
• orbitan.cpp