org.apache.commons.math3.ode.events

Class EventState

java.lang.Object

org.apache.commons.math3.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.

Since:

1.2

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	EventState.LocalMaxCountExceededException Local wrapper to propagate exceptions.

Field Summary

Fields

Modifier and Type	Field and Description
private double	convergence Convergence threshold for event localization.
private ExpandableStatefulODE	expandable Equation being integrated.
private boolean	forward Integration direction.
private double	g0 Value of the events handler at the beginning of the step.
private boolean	g0Positive Simulated sign of g0 (we cheat when crossing events).
private EventHandler	handler Event handler.
private boolean	increasing Variation direction around pending event.
private double	maxCheckInterval Maximal time interval between events handler checks.
private int	maxIterationCount Upper limit in the iteration count for event localization.
private EventHandler.Action	nextAction Next action indicator.
private boolean	pendingEvent Indicator of event expected during the step.
private double	pendingEventTime Occurrence time of the pending event.
private double	previousEventTime Occurrence time of the previous event.
private UnivariateSolver	solver Root-finding algorithm to use to detect state events.
private double	t0 Time at the beginning of the step.

Constructor Summary

Constructors

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

Method Summary

Methods

Modifier and Type	Method and Description
boolean	evaluateStep(StepInterpolator interpolator) Evaluate the impact of the proposed step on the event handler.
private double[]	getCompleteState(StepInterpolator interpolator) Get the complete state (primary and secondary).
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	setExpandable(ExpandableStatefulODE expandable) Set the equation.
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

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

Field Detail

handler

private final EventHandler handler

Event handler.

maxCheckInterval

private final double maxCheckInterval

Maximal time interval between events handler checks.

convergence

private final double convergence

Convergence threshold for event localization.

maxIterationCount

private final int maxIterationCount

Upper limit in the iteration count for event localization.

expandable

private ExpandableStatefulODE expandable

Equation being integrated.

t0

private double t0

Time at the beginning of the step.

g0

private double g0

Value of the events handler at the beginning of the step.

g0Positive

private boolean g0Positive

Simulated sign of g0 (we cheat when crossing events).

pendingEvent

private boolean pendingEvent

Indicator of event expected during the step.

pendingEventTime

private double pendingEventTime

Occurrence time of the pending event.

previousEventTime

private double previousEventTime

Occurrence time of the previous event.

forward

private boolean forward

Integration direction.

increasing

private boolean increasing

Variation direction around pending event. (this is considered with respect to the integration direction)

nextAction

private EventHandler.Action nextAction

Next action indicator.

solver

private final UnivariateSolver solver

Root-finding algorithm to use to detect state events.

Constructor Detail

EventState

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

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

solver - Root-finding algorithm to use to detect state events

Method Detail

getEventHandler

public EventHandler getEventHandler()

Get the underlying event handler.

Returns:

underlying event handler

setExpandable

public void setExpandable(ExpandableStatefulODE expandable)

Set the equation.

Parameters:

expandable - equation being integrated

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 MaxCountExceededException

Reinitialize the beginning of the step.

Parameters:

interpolator - valid for the current step

Throws:

MaxCountExceededException - if the interpolator throws one because the number of functions evaluations is exceeded

getCompleteState

private double[] getCompleteState(StepInterpolator interpolator)

Get the complete state (primary and secondary).

Parameters:

interpolator - interpolator to use

Returns:

complete state

evaluateStep

public boolean evaluateStep(StepInterpolator interpolator)
                     throws MaxCountExceededException,
                            NoBracketingException

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:

MaxCountExceededException - if the interpolator throws one because the number of functions evaluations is exceeded

NoBracketingException - if the event cannot be bracketed

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 infinity if no events are triggered

stepAccepted

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

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

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)

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