Package org.apache.commons.math3.ode

Interface FirstOrderFieldIntegrator<T extends RealFieldElement<T>>

Type Parameters:

T - the type of the field elements

All Known Implementing Classes:

AbstractFieldIntegrator, AdamsBashforthFieldIntegrator, AdamsFieldIntegrator, AdamsMoultonFieldIntegrator, AdaptiveStepsizeFieldIntegrator, ClassicalRungeKuttaFieldIntegrator, DormandPrince54FieldIntegrator, DormandPrince853FieldIntegrator, EmbeddedRungeKuttaFieldIntegrator, EulerFieldIntegrator, GillFieldIntegrator, HighamHall54FieldIntegrator, LutherFieldIntegrator, MidpointFieldIntegrator, MultistepFieldIntegrator, RungeKuttaFieldIntegrator, ThreeEighthesFieldIntegrator

public interface FirstOrderFieldIntegrator<T extends RealFieldElement<T>>

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 FirstOrderDifferentialEquations interface.

Since:

3.6

See Also:

• FirstOrderFieldDifferentialEquations

Method Summary

Modifier and Type	Method	Description
void	addEventHandler(FieldEventHandler<T> handler, double maxCheckInterval, double convergence, int maxIterationCount)	Add an event handler to the integrator.
void	addEventHandler(FieldEventHandler<T> handler, double maxCheckInterval, double convergence, int maxIterationCount, BracketedRealFieldUnivariateSolver<T> solver)	Add an event handler to the integrator.
void	addStepHandler(FieldStepHandler<T> handler)	Add a step handler to this integrator.
void	clearEventHandlers()	Remove all the event handlers that have been added to the integrator.
void	clearStepHandlers()	Remove all the step handlers that have been added to the integrator.
T	getCurrentSignedStepsize()	Get the current signed value of the integration stepsize.
FieldODEStateAndDerivative<T>	getCurrentStepStart()	Get the current value of the step start time ti.
int	getEvaluations()	Get the number of evaluations of the differential equations function.
Collection<FieldEventHandler<T>>	getEventHandlers()	Get all the event handlers that have been added to the integrator.
int	getMaxEvaluations()	Get the maximal number of functions evaluations.
String	getName()	Get the name of the method.
Collection<FieldStepHandler<T>>	getStepHandlers()	Get all the step handlers that have been added to the integrator.
FieldODEStateAndDerivative<T>	integrate(FieldExpandableODE<T> equations, FieldODEState<T> initialState, T finalTime)	Integrate the differential equations up to the given time.
void	setMaxEvaluations(int maxEvaluations)	Set the maximal number of differential equations function evaluations.

Method Details

getName

String getName()

Get the name of the method.

Returns:

name of the method

addStepHandler

void addStepHandler(FieldStepHandler<T> 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

Collection<FieldStepHandler<T>> 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(FieldStepHandler)
• clearStepHandlers()

clearStepHandlers

void clearStepHandlers()

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

See Also:

• addStepHandler(FieldStepHandler)
• getStepHandlers()

addEventHandler

void addEventHandler(FieldEventHandler<T> handler,
 double maxCheckInterval,
 double convergence,
 int maxIterationCount)

Add an event handler to the integrator.

The default solver is a 5^th order FieldBracketingNthOrderBrentSolver.

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 events.

See Also:

• addEventHandler(FieldEventHandler, double, double, int, org.apache.commons.math3.analysis.solvers.BracketedRealFieldUnivariateSolver)
• getEventHandlers()
• clearEventHandlers()

addEventHandler

void addEventHandler(FieldEventHandler<T> handler,
 double maxCheckInterval,
 double convergence,
 int maxIterationCount,
 BracketedRealFieldUnivariateSolver<T> solver)

Add an event handler to the integrator.

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 events.

solver - solver to use to locate the event

See Also:

• addEventHandler(FieldEventHandler, double, double, int)
• getEventHandlers()
• clearEventHandlers()

getEventHandlers

Collection<FieldEventHandler<T>> getEventHandlers()

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

Returns:

an unmodifiable collection of the added events handlers

See Also:

• addEventHandler(FieldEventHandler, double, double, int)
• clearEventHandlers()

clearEventHandlers

void clearEventHandlers()

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

See Also:

• addEventHandler(FieldEventHandler, double, double, int)
• getEventHandlers()

getCurrentStepStart

FieldODEStateAndDerivative<T> getCurrentStepStart()

Get the current value of the 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:

current value of the state at step start time t_i

getCurrentSignedStepsize

T 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

FieldODEStateAndDerivative<T> integrate(FieldExpandableODE<T> equations,
 FieldODEState<T> initialState,
 T finalTime)
                                 throws NumberIsTooSmallException,
MaxCountExceededException,
NoBracketingException

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 FieldEventHandler stops it at some point.

Throws:

NumberIsTooSmallException - if integration step is too small

MaxCountExceededException - if the number of functions evaluations is exceeded

NoBracketingException - if the location of an event cannot be bracketed