fr.cnes.sirius.patrius.stela.propagation

Class StelaDifferentialEquations

java.lang.Object

fr.cnes.sirius.patrius.stela.propagation.StelaDifferentialEquations

All Implemented Interfaces:

FirstOrderDifferentialEquations

public class StelaDifferentialEquations
extends Object
implements FirstOrderDifferentialEquations

Class representing the differential system of a STELA GTO propagation. It implements a Commons-Math first order differential equations system.

Forces contributions to dE'/dt are computed and summed in this class (E' being the state vector of the mean orbital parameters).

Since:

1.3

Version:

$Id$

Author:

Tiziana Sabatini

Concurrency :

not thread-safe

Concurrency comment :

not thread-safe due to use of mutable attributes

Field Summary

Fields

Modifier and Type	Field and Description
static int	STATE_SIZE Size of the state vector.
protected boolean	tesseralComputed Required for step computation of the tesseral quads

Constructor Summary

Constructors

Constructor and Description
StelaDifferentialEquations(StelaGTOPropagator inStelaPropagator) Build a new instance of the Stela differential equations.

Method Summary

Modifier and Type	Method and Description
void	computeDerivatives(double t, double[] y, double[] yDot) Get the current time derivative of the state vector.
protected void	gaussForcesYDot(double[] yDot, StelaEquinoctialOrbit orbit) Compute the contribution of all Gauss forces.
int	getDimension() Get the dimension of the problem.
protected void	updateQuads(StelaEquinoctialOrbit orbit, StelaForceModel lagrange) Update quads for tesseral pertubations

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

STATE_SIZE

public static final int STATE_SIZE

Size of the state vector.

See Also:

Constant Field Values

tesseralComputed

protected boolean tesseralComputed

Required for step computation of the tesseral quads

Constructor Detail

StelaDifferentialEquations

public StelaDifferentialEquations(StelaGTOPropagator inStelaPropagator)
                           throws PatriusException

Build a new instance of the Stela differential equations.

Parameters:

inStelaPropagator - the Stela GTO propagator.

Throws:

PatriusException - exception in propagator

Method Detail

getDimension

public int getDimension()

Get the dimension of the problem.

Specified by:

getDimension in interface FirstOrderDifferentialEquations

Returns:

dimension of the problem

computeDerivatives

public void computeDerivatives(double t,
                               double[] y,
                               double[] yDot)

Get the current time derivative of the state vector.

Specified by:

computeDerivatives in interface FirstOrderDifferentialEquations

Parameters:

t - current value of the independent time variable

y - array containing the current value of the state vector

yDot - placeholder array where to put the time derivative of the state vector

updateQuads

protected void updateQuads(StelaEquinoctialOrbit orbit,
                           StelaForceModel lagrange)

Update quads for tesseral pertubations

Parameters:

orbit - orbit

lagrange - Lagrange force model

gaussForcesYDot

protected void gaussForcesYDot(double[] yDot,
                               StelaEquinoctialOrbit orbit)
                        throws PatriusException

Compute the contribution of all Gauss forces.

Parameters:

yDot - the time derivative of the state vector

orbit - the current orbit

Throws:

PatriusException - error when computing perturbations