INBodyIntegrator Interface Reference

Common interface for numerical NBody integration. Used by the GravityEngine. More...

Inheritance diagram for INBodyIntegrator:

Public Member Functions
void	Setup (int maxBodies, double timeStep)
	Setup the specified maxBodies and timeStep. Must be called prior to PreEvolve/Evolve.
void	Clear ()
	Clear internal information so no bodies are evolved.
INBodyIntegrator	DeepClone ()
	Clone this instance, replicating internal arrays. Copy across any internal state required for continued evolution.
void	AddNBody (int bodyNum, NBody nbody, GravityState.NbodyState[] nbodyState)
	Adds the N body. Implementation may support the case where the initial number of bodies in Setup() is exceeded, creating space, or may ignore additions that exceed this limit (e.g. AZTTriple).
void	RemoveBodyAtIndex (int atIndex)
	Removes NBody at index i.
void	GrowArrays (int growBy)
	Grows the arrays. Called by GravityEngine when it changes internal data sizes.
Vector3d	GetAccelerationForIndex (int i)
string	GetExternalAccelForIndex (int i)
void	PreEvolve (GravityState gravityState)
	Call ONCE after all game objects have been added to allow integrator to pre-calc starting quantities required for integration.
double	Evolve (double time, GravityState gravityState, bool exactTime=false)
	Evolve the specified time, m, r and info.
float	GetEnergy (GravityState gs)
	Gets the energy of the system.
float	GetInitialEnergy (GravityState gs)
	Gets the initial energy.

Detailed Description

Common interface for numerical NBody integration. Used by the GravityEngine.

Index Tracking:

• GravityEngine tracks adds/removes and maintains an index list. The positions and velocities are in arrays in gravity engine (since they are common to all bodies and needed for game object position updates)

This interface is not normally called from developer scripts.

Member Function Documentation

AddNBody()

void INBodyIntegrator.AddNBody	(	int	bodyNum,
		NBody	nbody,
		GravityState.NbodyState[]	nbodyState
	)

Adds the N body. Implementation may support the case where the initial number of bodies in Setup() is exceeded, creating space, or may ignore additions that exceed this limit (e.g. AZTTriple).

Parameters

nbody

NBody component

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

Clear()

void INBodyIntegrator.Clear

(

)

Clear internal information so no bodies are evolved.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

DeepClone()

INBodyIntegrator INBodyIntegrator.DeepClone

(

)

Clone this instance, replicating internal arrays. Copy across any internal state required for continued evolution.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

Evolve()

double INBodyIntegrator.Evolve	(	double	time,
		GravityState	gravityState,
		bool	exactTime = false
	)

Evolve the specified time, m, r and info.

Integrators will evolve for at least as long as the specified time, but can overshoot. The GravityEngine will correct on the next cycle.

Parameters

time	Time.
m	M.
r	The red component.
info	Info.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

GetEnergy()

float INBodyIntegrator.GetEnergy

(

GravityState

gs

)

Gets the energy of the system.

Returns

The energy.

Parameters

mass	Mass.
pos	Position.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

GetInitialEnergy()

float INBodyIntegrator.GetInitialEnergy

(

GravityState

gs

)

Gets the initial energy.

Returns

The initial energy.

Parameters

mass	Mass.
pos	Position.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

GrowArrays()

void INBodyIntegrator.GrowArrays

(

int

growBy

)

Grows the arrays. Called by GravityEngine when it changes internal data sizes.

Parameters

growBy

Grow by.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

PreEvolve()

void INBodyIntegrator.PreEvolve

(

GravityState

gravityState

)

Call ONCE after all game objects have been added to allow integrator to pre-calc starting quantities required for integration.

To avoid copies of mass and position arrays in integrators provide a reference to these for Evolve and PreEvolve

Some implementations (e.g. AZTriple) may make their own copies and then copy the result back into these arrays ///

Parameters

m	M.
r	The red component.
info	Info.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

RemoveBodyAtIndex()

void INBodyIntegrator.RemoveBodyAtIndex

(

int

atIndex

)

Removes NBody at index i.

Parameters

atIndex

At index.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

Setup()

void INBodyIntegrator.Setup	(	int	maxBodies,
		double	timeStep
	)

Setup the specified maxBodies and timeStep. Must be called prior to PreEvolve/Evolve.

Parameters

maxBodies	Max bodies.
timeStep	Time step.

Implemented in AZTripleIntegrator, HermiteIntegrator, and LeapfrogIntegrator.

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

• C:/Users/musgr/Documents/Unity/gravityengine/Assets/GravityEngine/Scripts/Engine/Integrators/INBodyIntegrator.cs