org.apache.commons.math.ode.events

Class EventState

java.lang.Object

org.apache.commons.math.ode.events.EventState

public class EventState
extends java.lang.Object

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

Each time the integrator proposes a step, the event handler switching function should be checked. This class handles the state of one handler during one integration step, with references to the state at the end of the preceding step. This information is used to decide if the handler 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).

Since:

1.2

Constructor Summary

Constructors

Constructor and Description
EventState(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount) Simple constructor.

Method Summary

Modifier and Type	Method and Description
boolean	evaluateStep(StepInterpolator interpolator) Evaluate the impact of the proposed step on the event handler.
double	getConvergence() Get the convergence threshold for event localization.
EventHandler	getEventHandler() Get the underlying event handler.
double	getEventTime() Get the occurrence time of the event triggered in the current step.
double	getMaxCheckInterval() Get the maximal time interval between events handler checks.
int	getMaxIterationCount() Get the upper limit in the iteration count for event localization.
void	reinitializeBegin(StepInterpolator interpolator) Reinitialize the beginning of the step.
boolean	reset(double t, double[] y) Let the event handler reset the state if it wants.
void	stepAccepted(double t, double[] y) Acknowledge the fact the step has been accepted by the integrator.
boolean	stop() Check if the integration should be stopped at the end of the current step.

Methods inherited from class java.lang.Object

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

Constructor Detail

EventState

public EventState(EventHandler handler,
                  double maxCheckInterval,
                  double convergence,
                  int maxIterationCount)

Simple constructor.

Parameters:

handler - event handler

maxCheckInterval - maximal time interval between switching function checks (this interval prevents missing sign changes in case the integration steps becomes very large)

convergence - convergence threshold in the event time search

maxIterationCount - upper limit of the iteration count in the event time search

Method Detail

getEventHandler

public EventHandler getEventHandler()

Get the underlying event handler.

Returns:

underlying event handler

getMaxCheckInterval

public double getMaxCheckInterval()

Get the maximal time interval between events handler checks.

Returns:

maximal time interval between events handler checks

getConvergence

public double getConvergence()

Get the convergence threshold for event localization.

Returns:

convergence threshold for event localization

getMaxIterationCount

public int getMaxIterationCount()

Get the upper limit in the iteration count for event localization.

Returns:

upper limit in the iteration count for event localization

reinitializeBegin

public void reinitializeBegin(StepInterpolator interpolator)
                       throws EventException

Reinitialize the beginning of the step.

Parameters:

interpolator - valid for the current step

Throws:

EventException - if the event handler value cannot be evaluated at the beginning of the step

evaluateStep

public boolean evaluateStep(StepInterpolator interpolator)
                     throws DerivativeException,
                            EventException,
                            ConvergenceException

Evaluate the impact of the proposed step on the event handler.

Parameters:

interpolator - step interpolator for the proposed step

Returns:

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

Throws:

DerivativeException - if the interpolator fails to compute the switching function somewhere within the step

EventException - if the switching function cannot be evaluated

ConvergenceException - if an event cannot be located

getEventTime

public double getEventTime()

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

Returns:

occurrence time of the event triggered in the current step or positive infinity if no events are triggered

stepAccepted

public void stepAccepted(double t,
                         double[] y)
                  throws EventException

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

Parameters:

t - value of the independent time variable at the end of the step

y - array containing the current value of the state vector at the end of the step

Throws:

EventException - if the value of the event handler cannot be evaluated

stop

public boolean stop()

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

Returns:

true if the integration should be stopped

reset

public boolean reset(double t,
                     double[] y)
              throws EventException

Let the event handler reset the state if it wants.

Parameters:

t - value of the independent time variable at the beginning of the next step

y - array were to put the desired state vector at the beginning of the next step

Returns:

true if the integrator should reset the derivatives too

Throws:

EventException - if the state cannot be reseted by the event handler