Package org.orekit.propagation.events

Class FieldBooleanDetector<T extends CalculusFieldElement<T>>

java.lang.Object

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

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

Type Parameters:

T - type of the field elements

All Implemented Interfaces:

FieldEventDetector<T>

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

This class provides AND and OR operations for event detectors. This class treats positive values of the g function as true and negative values as false.

One example for an imaging satellite might be to only detect events when a satellite is overhead (elevation > 0) AND when the ground point is sunlit (Sun elevation > 0). Another slightly contrived example using the OR operator would be to detect access to a set of ground stations and only report events when the satellite enters or leaves the field of view of the set, but not hand-offs between the ground stations.

For the FieldBooleanDetector is important that the sign of the g function of the underlying event detector is not arbitrary, but has a semantic meaning, e.g. in or out, true or false. This class works well with event detectors that detect entry to or exit from a region, e.g. FieldEclipseDetector, FieldElevationDetector, FieldLatitudeCrossingDetector. Using this detector with detectors that are not based on entry to or exit from a region, e.g. FieldDateDetector, will likely lead to unexpected results. To apply conditions to this latter type of event detectors a FieldEventEnablingPredicateFilter is usually more appropriate.

Since:

12.0

Author:

Evan Ward, luc Luc Maisonobe

See Also:

andCombine(Collection), orCombine(Collection), notCombine(FieldEventDetector), EventEnablingPredicateFilter, EventSlopeFilter

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	FieldBooleanDetector(List<FieldEventDetector<T>> detectors, org.orekit.propagation.events.FieldBooleanDetector.Operator operator, FieldAdaptableInterval<T> newMaxCheck, T newThreshold, int newMaxIter, FieldEventHandler<T> newHandler)	Private constructor with all the parameters.

Method Summary

Modifier and Type	Method	Description
static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T>	andCombine(Collection<? extends FieldEventDetector<T>> detectors)	Create a new event detector that is the logical AND of the given event detectors.
static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T>	andCombine(FieldEventDetector<T>... detectors)	Create a new event detector that is the logical AND of the given event detectors.
protected FieldBooleanDetector<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.
List<FieldEventDetector<T>>	getDetectors()	Get the list of original detectors.
void	init(FieldSpacecraftState<T> s0, FieldAbsoluteDate<T> t)	Initialize event handler at the start of a propagation.
static <T extends CalculusFieldElement<T>> FieldNegateDetector<T>	notCombine(FieldEventDetector<T> detector)	Create a new event detector that negates the g function of another detector.
static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T>	orCombine(Collection<? extends FieldEventDetector<T>> detectors)	Create a new event detector that is the logical OR of the given event detectors.
static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T>	orCombine(FieldEventDetector<T>... detectors)	Create a new event detector that is the logical OR of the given event detectors.

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

FieldBooleanDetector

protected FieldBooleanDetector(List<FieldEventDetector<T>> detectors,
                               org.orekit.propagation.events.FieldBooleanDetector.Operator operator,
                               FieldAdaptableInterval<T> newMaxCheck,
                               T newThreshold,
                               int newMaxIter,
                               FieldEventHandler<T> newHandler)

Private constructor with all the parameters.

Parameters:

detectors - the operands.

operator - reduction operator to apply to value of the g function of the operands.

newMaxCheck - max check interval.

newThreshold - convergence threshold in seconds.

newMaxIter - max iterations.

newHandler - event handler.

Method Detail

andCombine

@SafeVarargs
public static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T> andCombine(FieldEventDetector<T>... detectors)

Create a new event detector that is the logical AND of the given event detectors.

The created event detector's g function is positive if and only if the g functions of all detectors in detectors are positive.

The starting interval, threshold, and iteration count are set to the most stringent (minimum) of all the detectors. The event handlers of the underlying detectors are not used, instead the default handler is FieldContinueOnEvent.

Type Parameters:

T - type of the field elements

Parameters:

detectors - the operands. Must contain at least one detector.

Returns:

a new event detector that is the logical AND of the operands.

Throws:

NoSuchElementException - if detectors is empty.

See Also:

FieldBooleanDetector, andCombine(Collection), orCombine(FieldEventDetector...), notCombine(FieldEventDetector)

andCombine

public static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T> andCombine(Collection<? extends FieldEventDetector<T>> detectors)

Create a new event detector that is the logical AND of the given event detectors.

The created event detector's g function is positive if and only if the g functions of all detectors in detectors are positive.

The starting interval, threshold, and iteration count are set to the most stringent (minimum) of the detectors. The event handlers of the underlying detectors are not used, instead the default handler is FieldContinueOnEvent.

Type Parameters:

T - type of the field elements

Parameters:

detectors - the operands. Must contain at least one detector.

Returns:

a new event detector that is the logical AND of the operands.

Throws:

NoSuchElementException - if detectors is empty.

See Also:

FieldBooleanDetector, andCombine(FieldEventDetector...), orCombine(Collection), notCombine(FieldEventDetector)

orCombine

@SafeVarargs
public static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T> orCombine(FieldEventDetector<T>... detectors)

Create a new event detector that is the logical OR of the given event detectors.

The created event detector's g function is positive if and only if at least one of g functions of the event detectors in detectors is positive.

The starting interval, threshold, and iteration count are set to the most stringent (minimum) of the detectors. The event handlers of the underlying EventDetectors are not used, instead the default handler is FieldContinueOnEvent.

Type Parameters:

T - type of the field elements

Parameters:

detectors - the operands. Must contain at least one detector.

Returns:

a new event detector that is the logical OR of the operands.

Throws:

NoSuchElementException - if detectors is empty.

See Also:

FieldBooleanDetector, orCombine(Collection), andCombine(FieldEventDetector...), notCombine(FieldEventDetector)

orCombine

public static <T extends CalculusFieldElement<T>> FieldBooleanDetector<T> orCombine(Collection<? extends FieldEventDetector<T>> detectors)

Create a new event detector that is the logical OR of the given event detectors.

The created event detector's g function is positive if and only if at least one of g functions of the event detectors in detectors is positive.

The starting interval, threshold, and iteration count are set to the most stringent (minimum) of the detectors. The event handlers of the underlying EventDetectors are not used, instead the default handler is FieldContinueOnEvent.

Type Parameters:

T - type of the field elements

Parameters:

detectors - the operands. Must contain at least one detector.

Returns:

a new event detector that is the logical OR of the operands.

Throws:

NoSuchElementException - if detectors is empty.

See Also:

FieldBooleanDetector, orCombine(FieldEventDetector...), andCombine(Collection), notCombine(FieldEventDetector)

notCombine

public static <T extends CalculusFieldElement<T>> FieldNegateDetector<T> notCombine(FieldEventDetector<T> detector)

Create a new event detector that negates the g function of another detector.

This detector will be initialized with the same FieldEventDetector.getMaxCheckInterval(), FieldEventDetector.getThreshold(), and FieldEventDetector.getMaxIterationCount() as detector. The event handler of the underlying detector is not used, instead the default handler is FieldContinueOnEvent.

Type Parameters:

T - type of the field elements

Parameters:

detector - to negate.

Returns:

an new event detector whose g function is the same magnitude but opposite sign of detector.

See Also:

andCombine(Collection), orCombine(Collection), FieldBooleanDetector

g

public T g(FieldSpacecraftState<T> s)

Description copied from class: FieldAbstractDetector

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<FieldBooleanDetector<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

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

Returns:

value of the switching function

create

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

Description copied from class: FieldAbstractDetector

Build a new instance.

Specified by:

create in class FieldAbstractDetector<FieldBooleanDetector<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

init

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

Description copied from class: FieldAbstractDetector

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<FieldBooleanDetector<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

s0 - initial state

t - target time for the integration

getDetectors

public List<FieldEventDetector<T>> getDetectors()

Get the list of original detectors.

Returns:

the list of original detectors