org.apache.commons.math.ode
Class SwitchingFunctionsHandler

java.lang.Object
  org.apache.commons.math.ode.SwitchingFunctionsHandler

public class SwitchingFunctionsHandler
extends java.lang.Object

This class handles several switching functions during integration.

Since:

1.2

Version:

$Revision: 620312 $ $Date: 2008-02-10 12:28:59 -0700 (Sun, 10 Feb 2008) $

See Also:

SwitchingFunction

Constructor Summary

SwitchingFunctionsHandler()
Simple constructor.

Method Summary

void	add(SwitchingFunction function, double maxCheckInterval, double convergence, int maxIterationCount) Add a switching function.
boolean	evaluateStep(StepInterpolator interpolator) Evaluate the impact of the proposed step on all handled switching functions.
double	getEventTime() Get the occurrence time of the first event triggered in the last evaluated step.
boolean	isEmpty() Check if the handler does not have any condition.
boolean	reset(double t, double[] y) Let the switching functions reset the state if they want.
void	stepAccepted(double t, double[] y) Inform the switching functions that 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

Constructor Detail

SwitchingFunctionsHandler

public SwitchingFunctionsHandler()

Simple constructor. Create an empty handler

Method Detail

add

public void add(SwitchingFunction function,
                double maxCheckInterval,
                double convergence,
                int maxIterationCount)

Add a switching function.

Parameters:

function - switching function

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

isEmpty

public boolean isEmpty()

Check if the handler does not have any condition.

Returns:

true if handler is empty

evaluateStep

public boolean evaluateStep(StepInterpolator interpolator)
                     throws DerivativeException,
                            IntegratorException

Evaluate the impact of the proposed step on all handled switching functions.

Parameters:

interpolator - step interpolator for the proposed step

Returns:

true if at least one switching function triggers an event before the end of the proposed step (this implies the step should be rejected)

Throws:

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

IntegratorException - if an event cannot be located

getEventTime

public double getEventTime()

Get the occurrence time of the first event triggered in the last evaluated step.

Returns:

occurrence time of the first event triggered in the last evaluated step, or Double.NaN if no event is triggered

stepAccepted

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

Inform the switching functions that 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:

IntegratorException - if the value of one of the switching functions 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)

Let the switching functions reset the state if they want.

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