org.apache.commons.math.ode

Class AbstractIntegrator.EndTimeChecker

java.lang.Object

org.apache.commons.math.ode.AbstractIntegrator.EndTimeChecker

All Implemented Interfaces:

EventHandler

Enclosing class:

AbstractIntegrator

Deprecated.

as of 2.2, this class is not used anymore

@Deprecated
private static class AbstractIntegrator.EndTimeChecker
extends java.lang.Object
implements EventHandler

Specialized event handler to stop integration.

Field Summary

Fields

Modifier and Type	Field and Description
private double	endTime Deprecated. Desired end time.

Fields inherited from interface org.apache.commons.math.ode.events.EventHandler

CONTINUE, RESET_DERIVATIVES, RESET_STATE, STOP

Constructor Summary

Constructors

Constructor and Description
EndTimeChecker(double endTime) Deprecated. Build an instance.

Method Summary

Modifier and Type	Method and Description
int	eventOccurred(double t, double[] y, boolean increasing) Deprecated. Handle an event and choose what to do next.
double	g(double t, double[] y) Deprecated. Compute the value of the switching function.
void	resetState(double t, double[] y) Deprecated. Reset the state prior to continue the integration.

Methods inherited from class java.lang.Object

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

Field Detail

endTime

private final double endTime

Deprecated.

Desired end time.

Constructor Detail

EndTimeChecker

public EndTimeChecker(double endTime)

Deprecated.

Build an instance.

Parameters:

endTime - desired time

Method Detail

eventOccurred

public int eventOccurred(double t,
                         double[] y,
                         boolean increasing)

Deprecated.

Handle an event and choose what to do next.

This method is called when the integrator has accepted a step ending exactly on a sign change of the function, just before the step handler itself is called (see below for scheduling). It allows the user to update his internal data to acknowledge the fact the event has been handled (for example setting a flag in the differential equations to switch the derivatives computation in case of discontinuity), or to direct the integrator to either stop or continue integration, possibly with a reset state or derivatives.

• if EventHandler.STOP is returned, the step handler will be called with the isLast flag of the handleStep method set to true and the integration will be stopped,
• if EventHandler.RESET_STATE is returned, the resetState method will be called once the step handler has finished its task, and the integrator will also recompute the derivatives,
• if EventHandler.RESET_DERIVATIVES is returned, the integrator will recompute the derivatives,
• if EventHandler.CONTINUE is returned, no specific action will be taken (apart from having called this method) and integration will continue.

The scheduling between this method and the StepHandler method handleStep(interpolator, isLast) is to call this method first and handleStep afterwards. This scheduling allows the integrator to pass true as the isLast parameter to the step handler to make it aware the step will be the last one if this method returns EventHandler.STOP. As the interpolator may be used to navigate back throughout the last step (as StepNormalizer does for example), user code called by this method and user code called by step handlers may experience apparently out of order values of the independent time variable. As an example, if the same user object implements both this EventHandler interface and the FixedStepHandler interface, a forward integration may call its eventOccurred method with t = 10 first and call its handleStep method with t = 9 afterwards. Such out of order calls are limited to the size of the integration step for variable step handlers and to the size of the fixed step for fixed step handlers.

Specified by:

eventOccurred in interface EventHandler

Parameters:

t - current value of the independent time variable

y - array containing the current value of the state vector

increasing - if true, the value of the switching function increases when times increases around event (note that increase is measured with respect to physical time, not with respect to integration which may go backward in time)

Returns:

indication of what the integrator should do next, this value must be one of EventHandler.STOP, EventHandler.RESET_STATE, EventHandler.RESET_DERIVATIVES or EventHandler.CONTINUE

g

public double g(double t,
                double[] y)

Deprecated.

Compute the value of the switching function.

The discrete events are generated when the sign of this switching function changes. The integrator will take care to change the stepsize in such a way these events occur exactly at step boundaries. The switching function must be continuous in its roots neighborhood (but not necessarily smooth), as the integrator will need to find its roots to locate precisely the events.

Specified by:

g in interface EventHandler

Parameters:

t - current value of the independent time variable

y - array containing the current value of the state vector

Returns:

value of the g switching function

resetState

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

Deprecated.

Reset the state prior to continue the integration.

This method is called after the step handler has returned and before the next step is started, but only when EventHandler.eventOccurred(double, double[], boolean) has itself returned the EventHandler.RESET_STATE indicator. It allows the user to reset the state vector for the next step, without perturbing the step handler of the finishing step. If the EventHandler.eventOccurred(double, double[], boolean) never returns the EventHandler.RESET_STATE indicator, this function will never be called, and it is safe to leave its body empty.

Specified by:

resetState in interface EventHandler

Parameters:

t - current value of the independent time variable

y - array containing the current value of the state vector the new state should be put in the same array