org.hipparchus.ode

## Class AbstractIntegrator

• ### Constructor Summary

Constructors
Modifier Constructor and Description
protected  AbstractIntegrator(String name)
Build an instance.
• ### Method Summary

All Methods
Modifier and Type Method and Description
protected ODEStateAndDerivative acceptStep(AbstractODEStateInterpolator interpolator, double tEnd)
Accept a step, triggering events and step handlers.
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[] computeDerivatives(double t, double[] y)
Compute the derivatives and check the number of evaluations.
double getCurrentSignedStepsize()
Get the current signed value of the integration stepsize.
protected ExpandableODE getEquations()
Get the differential equations to integrate.
int getEvaluations()
Get the number of evaluations of the differential equations function.
protected Incrementor getEvaluationsCounter()
Get the evaluations counter.
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.
protected double getStepSize()
Get the current step size.
ODEStateAndDerivative getStepStart()
Get the state at step start time ti.
protected ODEStateAndDerivative initIntegration(ExpandableODE eqn, ODEState s0, double t)
Prepare the start of an integration.
protected boolean isLastStep()
Check if this step is the last one.
protected boolean resetOccurred()
Check if a reset occurred while last step was accepted.
protected void sanityChecks(ODEState initialState, double t)
Check the integration span.
protected void setIsLastStep(boolean isLastStep)
Set the last state flag.
void setMaxEvaluations(int maxEvaluations)
Set the maximal number of differential equations function evaluations.
protected void setStateInitialized(boolean stateInitialized)
Set the stateInitialized flag.
protected void setStepSize(double stepSize)
Set the current step size.
protected void setStepStart(ODEStateAndDerivative stepStart)
Set current step start.
• ### Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• ### Methods inherited from interface org.hipparchus.ode.ODEIntegrator

integrate, integrate
• ### Constructor Detail

• #### AbstractIntegrator

protected AbstractIntegrator(String name)
Build an instance.
Parameters:
name - name of the method
• ### Method Detail

• #### getName

public String getName()
Get the name of the method.
Specified by:
getName in interface ODEIntegrator
Returns:
name of the method

public void addStepHandler(ODEStepHandler handler)
Add a step handler to this integrator.

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

Specified by:
addStepHandler in interface ODEIntegrator
Parameters:
handler - handler for the accepted steps
ODEIntegrator.getStepHandlers(), ODEIntegrator.clearStepHandlers()

public 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.

Specified by:
addEventHandler in interface ODEIntegrator
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
ODEIntegrator.getEventHandlers(), ODEIntegrator.getEventHandlersConfigurations(), ODEIntegrator.clearEventHandlers()

public void addEventHandler(ODEEventHandler handler,
double maxCheckInterval,
double convergence,
int maxIterationCount,
BracketedUnivariateSolver<UnivariateFunction> solver)
Add an event handler to the integrator.
Specified by:
addEventHandler in interface ODEIntegrator
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.
ODEIntegrator.getEventHandlers(), ODEIntegrator.getEventHandlersConfigurations(), ODEIntegrator.clearEventHandlers()
• #### getCurrentSignedStepsize

public 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.

Specified by:
getCurrentSignedStepsize in interface ODEIntegrator
Returns:
current signed value of the stepsize
• #### setMaxEvaluations

public 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.

Specified by:
setMaxEvaluations in interface ODEIntegrator
Parameters:
maxEvaluations - maximal number of function evaluations (negative values are silently converted to maximal integer value, thus representing almost unlimited evaluations)
• #### getMaxEvaluations

public int getMaxEvaluations()
Get the maximal number of functions evaluations.
Specified by:
getMaxEvaluations in interface ODEIntegrator
Returns:
maximal number of functions evaluations
• #### getEvaluations

public 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.

Specified by:
getEvaluations in interface ODEIntegrator
Returns:
number of evaluations of the differential equations function
• #### initIntegration

protected ODEStateAndDerivative initIntegration(ExpandableODE eqn,
ODEState s0,
double t)
Prepare the start of an integration.
Parameters:
eqn - equations to integrate
s0 - initial state vector
t - target time for the integration
Returns:
Initial state with computed derivatives.
• #### getEquations

protected ExpandableODE getEquations()
Get the differential equations to integrate.
Returns:
differential equations to integrate
• #### getEvaluationsCounter

protected Incrementor getEvaluationsCounter()
Get the evaluations counter.
Returns:
evaluations counter
• #### computeDerivatives

public double[] computeDerivatives(double t,
double[] y)
throws MathIllegalArgumentException,
MathIllegalStateException,
NullPointerException
Compute the derivatives and check the number of evaluations.
Parameters:
t - current value of the independent time variable
y - array containing the current value of the state vector
Returns:
state completed with derivatives
Throws:
MathIllegalArgumentException - if arrays dimensions do not match equations settings
MathIllegalStateException - if the number of functions evaluations is exceeded
NullPointerException - if the ODE equations have not been set (i.e. if this method is called outside of a call to integrate
• #### setStateInitialized

protected void setStateInitialized(boolean stateInitialized)
Set the stateInitialized flag.

This method must be called by integrators with the value false before they start integration, so a proper lazy initialization is done automatically on the first step.

Parameters:
stateInitialized - new value for the flag
• #### acceptStep

protected ODEStateAndDerivative acceptStep(AbstractODEStateInterpolator interpolator,
double tEnd)
throws MathIllegalArgumentException,
MathIllegalStateException
Accept a step, triggering events and step handlers.
Parameters:
interpolator - step interpolator
tEnd - final integration time
Returns:
state at end of step
Throws:
MathIllegalStateException - if the interpolator throws one because the number of functions evaluations is exceeded
MathIllegalArgumentException - if the location of an event cannot be bracketed
MathIllegalArgumentException - if arrays dimensions do not match equations settings
• #### sanityChecks

protected void sanityChecks(ODEState initialState,
double t)
throws MathIllegalArgumentException
Check the integration span.
Parameters:
initialState - initial state
t - target time for the integration
Throws:
MathIllegalArgumentException - if integration span is too small
MathIllegalArgumentException - if adaptive step size integrators tolerance arrays dimensions are not compatible with equations settings
• #### resetOccurred

protected boolean resetOccurred()
Check if a reset occurred while last step was accepted.
Returns:
true if a reset occurred while last step was accepted
• #### setStepSize

protected void setStepSize(double stepSize)
Set the current step size.
Parameters:
stepSize - step size to set
• #### getStepSize

protected double getStepSize()
Get the current step size.
Returns:
current step size
• #### setStepStart

protected void setStepStart(ODEStateAndDerivative stepStart)
Set current step start.
Parameters:
stepStart - step start
• #### getStepStart

public 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.

Specified by:
getStepStart in interface ODEIntegrator
Returns:
state at step start time ti
• #### setIsLastStep

protected void setIsLastStep(boolean isLastStep)
Set the last state flag.
Parameters:
isLastStep - if true, this step is the last one
• #### isLastStep

protected boolean isLastStep()
Check if this step is the last one.
Returns:
true if this step is the last one