org.hipparchus.ode

Interface ODEIntegrator

• Method Summary

All Methods
Modifier and Type Method and Description
void addEventHandler(ODEEventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount)
Add an event handler to the integrator.
void addEventHandler(ODEEventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, BracketedUnivariateSolver<UnivariateFunction> solver)
Add an event handler to the integrator.
void addStepHandler(ODEStepHandler 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.
double getCurrentSignedStepsize()
Get the current signed value of the integration stepsize.
int getEvaluations()
Get the number of evaluations of the differential equations function.
Collection<ODEEventHandler> getEventHandlers()
Get all the event handlers that have been added to the integrator.
Collection<EventHandlerConfiguration> getEventHandlersConfigurations()
Get all the event handlers configurations 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<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

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
getStepHandlers(), clearStepHandlers()

void addEventHandler(ODEEventHandler handler,
double maxCheckInterval,
double convergence,
int maxIterationCount)
Add an event handler to the integrator.

Uses a default UnivariateSolver with an absolute accuracy equal to the given convergence threshold, as root-finding algorithm to detect the state events.

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. Must be smaller than maxCheckInterval and should be small compared to time scale of the ODE dynamics.
maxIterationCount - upper limit of the iteration count in the event time search
getEventHandlers(), getEventHandlersConfigurations(), clearEventHandlers()

void addEventHandler(ODEEventHandler handler,
double maxCheckInterval,
double convergence,
int maxIterationCount,
BracketedUnivariateSolver<UnivariateFunction> 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. Must be smaller than maxCheckInterval and should be small compared to time scale of the ODE dynamics.
maxIterationCount - upper limit of the iteration count in the event time search
solver - The root-finding algorithm to use to detect the state events.
getEventHandlers(), getEventHandlersConfigurations(), clearEventHandlers()
• getStepStart

ODEStateAndDerivative getStepStart()
Get the state at step start time ti.

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 ti
• 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