fr.cnes.sirius.patrius.events

Class MultiAbstractDetector

java.lang.Object

fr.cnes.sirius.patrius.events.MultiAbstractDetector

All Implemented Interfaces:

MultiEventDetector

Direct Known Subclasses:

OneSatEventDetectorWrapper

public abstract class MultiAbstractDetector
extends Object
implements MultiEventDetector

This class is copied from AbstractDetector and adapted to multi propagation.

Common parts shared by several events finders. A default implementation of most of the methods of MultiEventDetector interface. Make it easier to create a new detector.

Since:

3.0

Version:

$Id$

Author:

maggioranic

See Also:

MultiPropagator.addEventDetector(MultiEventDetector)

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_MAX_ITERATION_COUNT Default maximal number of iterations in the event time search.
static double	DEFAULT_MAXCHECK Default maximum checking interval (s).
static double	DEFAULT_THRESHOLD Default convergence threshold (s).

Fields inherited from interface fr.cnes.sirius.patrius.events.MultiEventDetector

DECREASING, INCREASING, INCREASING_DECREASING

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MultiAbstractDetector(double maxCheck, double threshold) Build a new instance.
	MultiAbstractDetector(int slopeSelection, double maxCheck, double threshold) Build a new instance.

Method Summary

Modifier and Type	Method and Description
abstract EventDetector.Action	eventOccurred(Map<String,SpacecraftState> s, boolean increasing, boolean forward) Handle an event and choose what to do next.
boolean	filterEvent(Map<String,SpacecraftState> states, boolean increasing, boolean forward) Filter last event: returns true if the last event is a false detection, false otherwise.
abstract double	g(Map<String,SpacecraftState> s) Compute the value of the switching function.
double	getMaxCheckInterval() Get maximal time interval between switching function checks.
int	getMaxIterationCount() Get maximal number of iterations in the event time search.
int	getSlopeSelection() Get the parameter in charge of the selection of detected events by the slope of the g-function.
double	getThreshold() Get the convergence threshold in the event time search.
void	init(Map<String,SpacecraftState> s0, AbsoluteDate t) Initialize event handler at the start of a propagation.
Map<String,SpacecraftState>	resetStates(Map<String,SpacecraftState> oldStates) Reset the states (including additional states) prior to continue propagation.
abstract boolean	shouldBeRemoved() This method is called after the step handler has returned and before the next step is started, but only when MultiEventDetector.eventOccurred(java.util.Map<java.lang.String, fr.cnes.sirius.patrius.propagation.SpacecraftState>, boolean, boolean) has been called.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAXCHECK

public static final double DEFAULT_MAXCHECK

Default maximum checking interval (s).

See Also:

Constant Field Values

DEFAULT_THRESHOLD

public static final double DEFAULT_THRESHOLD

Default convergence threshold (s).

See Also:

Constant Field Values

DEFAULT_MAX_ITERATION_COUNT

public static final int DEFAULT_MAX_ITERATION_COUNT

Default maximal number of iterations in the event time search.

See Also:

Constant Field Values

Constructor Detail

MultiAbstractDetector

protected MultiAbstractDetector(double maxCheck,
                                double threshold)

Build a new instance. The detector will detect both ascending and descending g-function related events.

Parameters:

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

MultiAbstractDetector

public MultiAbstractDetector(int slopeSelection,
                             double maxCheck,
                             double threshold)

Build a new instance.

Parameters:

slopeSelection - g-function slope selection (0, 1, or 2)

maxCheck - maximum checking interval (s)

threshold - convergence threshold (s)

Method Detail

init

public void init(Map<String,SpacecraftState> s0,
                 AbsoluteDate t)
          throws PatriusException

Initialize event handler at the start of a propagation.

This method is called once at the start of the propagation. It may be used by the event handler to initialize some internal data if needed.

Specified by:

init in interface MultiEventDetector

Parameters:

s0 - map of initial states

t - target time for the integration

Throws:

PatriusException - thrown if initialization failed

g

public abstract double g(Map<String,SpacecraftState> s)
                  throws PatriusException

Compute the value of the switching function.

This function must be continuous (at least in its roots neighborhood), as the integrator will need to find its roots to locate the events.

Specified by:

g in interface MultiEventDetector

Parameters:

s - the current states information: date, kinematics, attitudes for forces and events computation, and additional states for each states

Returns:

value of the switching function

Throws:

PatriusException - if some specific error occurs

eventOccurred

public abstract EventDetector.Action eventOccurred(Map<String,SpacecraftState> s,
                                                   boolean increasing,
                                                   boolean forward)
                                            throws PatriusException

Handle an event and choose what to do next.

The scheduling between this method and the MultiOrekitStepHandler method handleStep is to call this method first and handleStep afterwards. This scheduling allows the propagator to pass true as the isLast parameter to the step handler to make it aware the step will be the last one if this method returns EventDetector.Action.STOP. As the interpolator may be used to navigate back throughout the last step MultiOrekitStepNormalizer does for example), user code called by this method and user code called by step handlers may experience apparently out of order values of the independent time variable. As an example, if the same user object implements both this MultiEventDetector interface and the MultiOrekitFixedStepHandler interface, a forward integration may call its eventOccurred method with a state at 2000-01-01T00:00:10 first and call its handleStep method with a state at 2000-01-01T00:00:09 afterwards. Such out of order calls are limited to the size of the integration step for MultiOrekitStepHandler and to the size of the fixed step for MultiOrekitFixedStepHandler.

Specified by:

eventOccurred in interface MultiEventDetector

Parameters:

s - the current states information: date, kinematics, attitude for forces and events computation, and additional states for each states

increasing - if true, the value of the switching function increases when times increases around event (note that increase is measured with respect to physical time, not with respect to propagation which may go backward in time)

forward - if true, the integration variable (time) increases during integration.

Returns:

one of EventDetector.Action.STOP, EventDetector.Action.RESET_STATE, EventDetector.Action.RESET_DERIVATIVES, EventDetector.Action.CONTINUE

Throws:

PatriusException - if some specific error occurs

shouldBeRemoved

public abstract boolean shouldBeRemoved()

This method is called after the step handler has returned and before the next step is started, but only when MultiEventDetector.eventOccurred(java.util.Map<java.lang.String, fr.cnes.sirius.patrius.propagation.SpacecraftState>, boolean, boolean) has been called.

Specified by:

shouldBeRemoved in interface MultiEventDetector

Returns:

true if the current detector should be removed

resetStates

public Map<String,SpacecraftState> resetStates(Map<String,SpacecraftState> oldStates)
                                        throws PatriusException

Reset the states (including additional states) prior to continue propagation.

This method is called after the step handler has returned and before the next step is started, but only when MultiEventDetector.eventOccurred(java.util.Map<java.lang.String, fr.cnes.sirius.patrius.propagation.SpacecraftState>, boolean, boolean) has itself returned the EventDetector.Action.RESET_STATE indicator. It allows the user to reset the state for the next step, without perturbing the step handler of the finishing step. If the MultiEventDetector.eventOccurred(java.util.Map<java.lang.String, fr.cnes.sirius.patrius.propagation.SpacecraftState>, boolean, boolean) never returns the EventDetector.Action.RESET_STATE indicator, this function will never be called, and it is safe to simply return null.

Specified by:

resetStates in interface MultiEventDetector

Parameters:

oldStates - old states

Returns:

new states

Throws:

PatriusException - if the states cannot be reseted

getThreshold

public double getThreshold()

Get the convergence threshold in the event time search.

Specified by:

getThreshold in interface MultiEventDetector

Returns:

convergence threshold (s)

getMaxCheckInterval

public double getMaxCheckInterval()

Get maximal time interval between switching function checks.

Specified by:

getMaxCheckInterval in interface MultiEventDetector

Returns:

maximal time interval (s) between switching function checks

getMaxIterationCount

public int getMaxIterationCount()

Get maximal number of iterations in the event time search.

Specified by:

getMaxIterationCount in interface MultiEventDetector

Returns:

maximal number of iterations in the event time search

getSlopeSelection

public int getSlopeSelection()

Get the parameter in charge of the selection of detected events by the slope of the g-function.

Specified by:

getSlopeSelection in interface MultiEventDetector

Returns:

EventDetector.INCREASING (0): events related to the increasing g-function;
EventDetector.DECREASING (1): events related to the decreasing g-function;
EventDetector.INCREASING_DECREASING (2): events related to both increasing and decreasing g-function.

filterEvent

public boolean filterEvent(Map<String,SpacecraftState> states,
                           boolean increasing,
                           boolean forward)
                    throws PatriusException

Filter last event: returns true if the last event is a false detection, false otherwise.

This method is called right before #eventOccurred(SpacecraftState, boolean, boolean) method.

This may be useful in order to filter some events in particular when angles are at stake (see for example LocalTimeAngleDetector).

Specified by:

filterEvent in interface MultiEventDetector

Parameters:

states - states at last event occurrence

increasing - if true, the value of the switching function increases when times increases around event (note that increase is measured with respect to physical time, not with respect to propagation which may go backward in time)

forward - if true, the integration variable (time) increases during integration.

Returns:

true if the last event is a false detection, false otherwise

Throws:

PatriusException - thrown if computation failed for some reasons