Package org.hipparchus.ode

Interface ODEIntegrator

All Known Implementing Classes:

AbstractIntegrator, AdamsBashforthIntegrator, AdamsIntegrator, AdamsMoultonIntegrator, AdaptiveStepsizeIntegrator, ClassicalRungeKuttaIntegrator, DormandPrince54Integrator, DormandPrince853Integrator, EmbeddedRungeKuttaIntegrator, EulerIntegrator, GillIntegrator, GraggBulirschStoerIntegrator, HighamHall54Integrator, LutherIntegrator, MidpointIntegrator, MultistepIntegrator, RungeKuttaIntegrator, ThreeEighthesIntegrator

public interface ODEIntegrator

This interface represents a first order integrator for differential equations.

The classes which are devoted to solve first order differential equations should implement this interface. The problems which can be handled should implement the OrdinaryDifferentialEquation interface.

See Also:

OrdinaryDifferentialEquation, ODEStepHandler, ODEEventHandler

Method Summary

Modifier and Type	Method	Description
void	addEventDetector(ODEEventDetector detector)	Add an event detector to the integrator.
void	addStepEndHandler(ODEStepEndHandler handler)	Add a handler for step ends to the integrator.
void	addStepHandler(ODEStepHandler handler)	Add a step handler to this integrator.
void	clearEventDetectors()	Remove all the event handlers that have been added to the integrator.
void	clearStepEndHandlers()	Remove all the handlers for step ends that have been added to the integrator.
void	clearStepHandlers()	Remove all the step handlers that have been added to the integrator.
double	getCurrentSignedStepsize()	Get the current signed value of the integration stepsize.
int	getEvaluations()	Get the number of evaluations of the differential equations function.
List<ODEEventDetector>	getEventDetectors()	Get all the event detectors that have been added to the integrator.
int	getMaxEvaluations()	Get the maximal number of functions evaluations.
String	getName()	Get the name of the method.
List<ODEStepEndHandler>	getStepEndHandlers()	Get all the handlers for step ends that have been added to the integrator.
List<ODEStepHandler>	getStepHandlers()	Get all the step handlers that have been added to the integrator.
ODEStateAndDerivative	getStepStart()	Get the state at step start time ti.
ODEStateAndDerivative	integrate(ExpandableODE equations, ODEState initialState, double finalTime)	Integrate the differential equations up to the given time.
default ODEStateAndDerivative	integrate(OrdinaryDifferentialEquation equations, ODEState initialState, double finalTime)	Integrate the differential equations up to the given time.
void	setMaxEvaluations(int maxEvaluations)	Set the maximal number of differential equations function evaluations.

Method Detail

getName

String getName()

Get the name of the method.

Returns:

name of the method

addStepHandler

void addStepHandler(ODEStepHandler handler)

Add a step handler to this integrator.

The handler will be called by the integrator for each accepted step.

Parameters:

handler - handler for the accepted steps

See Also:

getStepHandlers(), clearStepHandlers()

getStepHandlers

List<ODEStepHandler> getStepHandlers()

Get all the step handlers that have been added to the integrator.

Returns:

an unmodifiable collection of the added events handlers

See Also:

addStepHandler(ODEStepHandler), clearStepHandlers()

clearStepHandlers

void clearStepHandlers()

Remove all the step handlers that have been added to the integrator.

See Also:

addStepHandler(ODEStepHandler), getStepHandlers()

addEventDetector

void addEventDetector(ODEEventDetector detector)

Add an event detector to the integrator.

Parameters:

detector - event detector

Since:

3.0

See Also:

getEventDetectors(), clearEventDetectors()

getEventDetectors

List<ODEEventDetector> getEventDetectors()

Get all the event detectors that have been added to the integrator.

Returns:

an unmodifiable list of the added events detectors

Since:

3.0

See Also:

addEventDetector(ODEEventDetector), clearEventDetectors()

clearEventDetectors

void clearEventDetectors()

Remove all the event handlers that have been added to the integrator.

Since:

3.0

See Also:

addEventDetector(ODEEventDetector), getEventDetectors()

addStepEndHandler

void addStepEndHandler(ODEStepEndHandler handler)

Add a handler for step ends to the integrator.

The stepEndOccurred(state, forward) method of the handler will be called at each step end.

Parameters:

handler - handler for step ends

Since:

3.0

See Also:

getStepEndHandlers(), clearStepEndHandlers()

getStepEndHandlers

List<ODEStepEndHandler> getStepEndHandlers()

Get all the handlers for step ends that have been added to the integrator.

Returns:

an unmodifiable list of the added step end handlers

Since:

3.0

See Also:

addStepEndHandler(ODEStepEndHandler), clearStepEndHandlers()

clearStepEndHandlers

void clearStepEndHandlers()

Remove all the handlers for step ends that have been added to the integrator.

Since:

3.0

See Also:

addStepEndHandler(ODEStepEndHandler), getStepEndHandlers()

getStepStart

ODEStateAndDerivative getStepStart()

Get the state at step start time t_i.

This method can be called during integration (typically by the object implementing the differential equations problem) if the value of the current step that is attempted is needed.

The result is undefined if the method is called outside of calls to integrate.

Returns:

state at step start time t_i

getCurrentSignedStepsize

double getCurrentSignedStepsize()

Get the current signed value of the integration stepsize.

This method can be called during integration (typically by the object implementing the differential equations problem) if the signed value of the current stepsize that is tried is needed.

The result is undefined if the method is called outside of calls to integrate.

Returns:

current signed value of the stepsize

setMaxEvaluations

void setMaxEvaluations(int maxEvaluations)

Set the maximal number of differential equations function evaluations.

The purpose of this method is to avoid infinite loops which can occur for example when stringent error constraints are set or when lots of discrete events are triggered, thus leading to many rejected steps.

Parameters:

maxEvaluations - maximal number of function evaluations (negative values are silently converted to maximal integer value, thus representing almost unlimited evaluations)

getMaxEvaluations

int getMaxEvaluations()

Get the maximal number of functions evaluations.

Returns:

maximal number of functions evaluations

getEvaluations

int getEvaluations()

Get the number of evaluations of the differential equations function.

The number of evaluations corresponds to the last call to the integrate method. It is 0 if the method has not been called yet.

Returns:

number of evaluations of the differential equations function

integrate

ODEStateAndDerivative integrate(ExpandableODE equations,
                                ODEState initialState,
                                double finalTime)
                         throws MathIllegalArgumentException,
                                MathIllegalStateException

Integrate the differential equations up to the given time.

This method solves an Initial Value Problem (IVP).

Since this method stores some internal state variables made available in its public interface during integration (getCurrentSignedStepsize()), it is not thread-safe.

Parameters:

equations - differential equations to integrate

initialState - initial state (time, primary and secondary state vectors)

finalTime - target time for the integration (can be set to a value smaller than t0 for backward integration)

Returns:

final state, its time will be the same as finalTime if integration reached its target, but may be different if some ODEEventHandler stops it at some point.

Throws:

MathIllegalArgumentException - if integration step is too small

MathIllegalStateException - if the number of functions evaluations is exceeded

MathIllegalArgumentException - if the location of an event cannot be bracketed

integrate

default ODEStateAndDerivative integrate(OrdinaryDifferentialEquation equations,
                                        ODEState initialState,
                                        double finalTime)
                                 throws MathIllegalArgumentException,
                                        MathIllegalStateException

Integrate the differential equations up to the given time.

This method solves an Initial Value Problem (IVP).

Since this method stores some internal state variables made available in its public interface during integration (getCurrentSignedStepsize()), it is not thread-safe.

Parameters:

equations - differential equations to integrate

initialState - initial state (time, primary and secondary state vectors)

finalTime - target time for the integration (can be set to a value smaller than t0 for backward integration)

Returns:

final state, its time will be the same as finalTime if integration reached its target, but may be different if some ODEEventHandler stops it at some point.

Throws:

MathIllegalArgumentException - if integration step is too small

MathIllegalStateException - if the number of functions evaluations is exceeded

MathIllegalArgumentException - if the location of an event cannot be bracketed