Package org.orekit.propagation.events

Class FieldEventEnablingPredicateFilter<T extends CalculusFieldElement<T>>

java.lang.Object

org.orekit.propagation.events.FieldAbstractDetector<FieldEventEnablingPredicateFilter<T>,T>

org.orekit.propagation.events.FieldEventEnablingPredicateFilter<T>

Type Parameters:

T - type of the field elements

All Implemented Interfaces:

FieldEventDetector<T>

public class FieldEventEnablingPredicateFilter<T extends CalculusFieldElement<T>>
extends FieldAbstractDetector<FieldEventEnablingPredicateFilter<T>,T>

Wrapper used to detect events only when enabled by an external predicated function.

General events are defined implicitly by a g function crossing zero. This implies that during an orbit propagation, events are triggered at all zero crossings.

Sometimes, users would like to enable or disable events by themselves, for example to trigger them only for certain orbits, or to check elevation maximums only when elevation itself is positive (i.e. they want to discard elevation maximums below ground). In these cases, looking precisely for all events location and triggering events that will later be ignored is a waste of computing time.

Users can wrap a regular event detector in an instance of this class and provide this wrapping instance to a FieldPropagator in order to avoid wasting time looking for uninteresting events. The wrapper will intercept the calls to the g function and to the eventOccurred method in order to ignore uninteresting events. The wrapped regular event detector will the see only the interesting events, i.e. either only events that occur when a user-provided event enabling predicate function is true, ignoring all events that occur when the event enabling predicate function is false. The number of calls to the g function will also be reduced.

Since:

12.0

See Also:

FieldEventSlopeFilter

Field Summary

Fields inherited from class org.orekit.propagation.events.FieldAbstractDetector

DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	FieldEventEnablingPredicateFilter(FieldAdaptableInterval<T> maxCheck, T threshold, int maxIter, FieldEventHandler<T> handler, FieldEventDetector<T> rawDetector, FieldEnablingPredicate<T> enabler)	Protected constructor with full parameters.
	FieldEventEnablingPredicateFilter(FieldEventDetector<T> rawDetector, FieldEnablingPredicate<T> enabler)	Wrap an event detector.

Method Summary

Modifier and Type	Method	Description
protected FieldEventEnablingPredicateFilter<T>	create(FieldAdaptableInterval<T> newMaxCheck, T newThreshold, int newMaxIter, FieldEventHandler<T> newHandler)	Build a new instance.
T	g(FieldSpacecraftState<T> s)	Compute the value of the switching function.
FieldEventDetector<T>	getDetector()	Get the wrapped raw detector.
void	init(FieldSpacecraftState<T> s0, FieldAbsoluteDate<T> t)	Initialize event handler at the start of a propagation.

Methods inherited from class org.orekit.propagation.events.FieldAbstractDetector

getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, isForward, withHandler, withMaxCheck, withMaxCheck, withMaxIter, withThreshold

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldEventEnablingPredicateFilter

public FieldEventEnablingPredicateFilter(FieldEventDetector<T> rawDetector,
                                         FieldEnablingPredicate<T> enabler)

Wrap an event detector.

Parameters:

rawDetector - event detector to wrap

enabler - event enabling predicate function to use

FieldEventEnablingPredicateFilter

protected FieldEventEnablingPredicateFilter(FieldAdaptableInterval<T> maxCheck,
                                            T threshold,
                                            int maxIter,
                                            FieldEventHandler<T> handler,
                                            FieldEventDetector<T> rawDetector,
                                            FieldEnablingPredicate<T> enabler)

Protected constructor with full parameters.

This constructor is not public as users are expected to use the builder API with the various withXxx() methods to set up the instance in a readable manner without using a huge amount of parameters.

Parameters:

maxCheck - maximum checking interval

threshold - convergence threshold (s)

maxIter - maximum number of iterations in the event time search

handler - event handler to call at event occurrences

rawDetector - event detector to wrap

enabler - event enabling function to use

Method Detail

create

protected FieldEventEnablingPredicateFilter<T> create(FieldAdaptableInterval<T> newMaxCheck,
                                                      T newThreshold,
                                                      int newMaxIter,
                                                      FieldEventHandler<T> newHandler)

Build a new instance.

Specified by:

create in class FieldAbstractDetector<FieldEventEnablingPredicateFilter<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

newMaxCheck - maximum checking interval

newThreshold - convergence threshold (s)

newMaxIter - maximum number of iterations in the event time search

newHandler - event handler to call at event occurrences

Returns:

a new instance of the appropriate sub-type

getDetector

public FieldEventDetector<T> getDetector()

Get the wrapped raw detector.

Returns:

the wrapped raw detector

init

public void init(FieldSpacecraftState<T> s0,
                 FieldAbsoluteDate<T> t)

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.

The default implementation does nothing

Specified by:

init in interface FieldEventDetector<T extends CalculusFieldElement<T>>

Overrides:

init in class FieldAbstractDetector<FieldEventEnablingPredicateFilter<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

s0 - initial state

t - target time for the integration

g

public T g(FieldSpacecraftState<T> s)

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 FieldEventDetector<T extends CalculusFieldElement<T>>

Specified by:

g in class FieldAbstractDetector<FieldEventEnablingPredicateFilter<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

value of the switching function