fr.cnes.sirius.patrius.events.utils

Class EventState

java.lang.Object

fr.cnes.sirius.patrius.events.utils.EventState

All Implemented Interfaces:

Serializable

public class EventState
extends Object
implements Serializable

This class handles the state for one event detector during integration steps.

This class is heavily based on the class with the same name from the Apache commons-math library. The changes performed consist in replacing raw types (double and double arrays) with space dynamics types (AbsoluteDate, SpacecraftState).

Each time the propagator proposes a step, the event detector should be checked. This class handles the state of one detector during one propagation step, with references to the state at the end of the preceding step. This information is used to determine if the detector should trigger an event or not during the proposed step (and hence the step should be reduced to ensure the event occurs at a bound rather than inside the step).

See Orekit issue 110 for more information. Default constructor changed in order to instanciate a bracketing solver, to solve the bracketing exception.

Author:

Luc Maisonobe

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
EventState(EventDetector detectorIn) Simple constructor.
EventState(EventDetector detectorIn, UnivariateSolver solverIn) Constructor allowing the user to provide the solver used in switch detection.

Method Summary

Modifier and Type	Method and Description
void	cancelStepAccepted() Cancel stepAccepted call (does not cancel event).
boolean	evaluateStep(PatriusStepInterpolator interpolator) Evaluate the impact of the proposed step on the event detector. See Orekit issue 110 for more information.
boolean	evaluateStep(SpacecraftState state) Evaluate the impact of the proposed step on the event handler.
EventDetector	getEventDetector() Get the underlying event detector.
AbsoluteDate	getEventTime() Get the occurrence time of the event triggered in the current step.
AbsoluteDate	getT0() Getter for t0.
boolean	isPendingReset() Check if some reset is being triggered.
void	reinitializeBegin(SpacecraftState state0) Reinitialize the beginning of the step.
boolean	removeDetector() Check if the current detector should be removed at the end of the current step.
SpacecraftState	reset(SpacecraftState oldState) Let the event detector reset the state if it wants.
void	stepAccepted(SpacecraftState state) Acknowledge the fact the step has been accepted by the propagator.
boolean	stop() Check if the propagation should be stopped at the end of the current step.
void	storeState(SpacecraftState state, boolean forceUpdate) Reinitialize event state with provided time and state.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventState

public EventState(EventDetector detectorIn,
                  UnivariateSolver solverIn)

Constructor allowing the user to provide the solver used in switch detection.

Parameters:

detectorIn - monitored event detector

solverIn - the UnivariateSolver used in switch detection

EventState

public EventState(EventDetector detectorIn)

Simple constructor. The default solver used in switch detection is the Brent solver.

Parameters:

detectorIn - monitored event detector

Method Detail

getEventDetector

public EventDetector getEventDetector()

Get the underlying event detector.

Returns:

underlying event detector

reinitializeBegin

public void reinitializeBegin(SpacecraftState state0)
                       throws PatriusException

Reinitialize the beginning of the step.

Parameters:

state0 - state value at the beginning of the step

Throws:

PatriusException - if the event detector value cannot be evaluated at the beginning of the step

isPendingReset

public boolean isPendingReset()

Check if some reset is being triggered.

Returns:

true is some reset is being triggered

storeState

public void storeState(SpacecraftState state,
                       boolean forceUpdate)
                throws PatriusException

Reinitialize event state with provided time and state.

Parameters:

state - SpacecraftState current state

forceUpdate - force update of event parameters

Throws:

PatriusException - SpacecraftState

evaluateStep

public boolean evaluateStep(SpacecraftState state)
                     throws PatriusException

Evaluate the impact of the proposed step on the event handler. In that case, the step is of null size (the provided date should be equal to t0)

Parameters:

state - current state

Returns:

true if the event handler triggers an event before the end of the proposed step

Throws:

PatriusException - SpacecraftState

evaluateStep

public boolean evaluateStep(PatriusStepInterpolator interpolator)
                     throws PatriusException

Evaluate the impact of the proposed step on the event detector.
See Orekit issue 110 for more information. Default constructor changed in order to instanciate a bracketing solver, to solve the bracketing exception.

Parameters:

interpolator - step interpolator for the proposed step

Returns:

true if the event detector triggers an event before the end of the proposed step (this implies the step should be rejected)

Throws:

PatriusException - if the switching function cannot be evaluated

TooManyEvaluationsException - if an event cannot be located

NoBracketingException - if bracketing cannot be performed

getEventTime

public AbsoluteDate getEventTime()

Get the occurrence time of the event triggered in the current step.

Returns:

occurrence time of the event triggered in the current step.

stepAccepted

public void stepAccepted(SpacecraftState state)
                  throws PatriusException

Acknowledge the fact the step has been accepted by the propagator.

Parameters:

state - value of the state vector at the end of the step

Throws:

PatriusException - if the value of the switching function cannot be evaluated

cancelStepAccepted

public void cancelStepAccepted()

Cancel stepAccepted call (does not cancel event). This method is used only when some missed event have occurred: event search algorithm goes backward in time, rewriting the future: stepAccepted() call leading to this jump in the past needs to be canceled.

getT0

public AbsoluteDate getT0()

Getter for t0.

Returns:

t0

stop

public boolean stop()

Check if the propagation should be stopped at the end of the current step.

Returns:

true if the propagation should be stopped

removeDetector

public boolean removeDetector()

Check if the current detector should be removed at the end of the current step.

Returns:

true if the detector should be removed

reset

public SpacecraftState reset(SpacecraftState oldState)
                      throws PatriusException

Let the event detector reset the state if it wants.

Parameters:

oldState - value of the state vector at the beginning of the next step

Returns:

new state (null if no reset is needed)

Throws:

PatriusException - if the state cannot be reset by the event detector