AbstractIntegrator (Apache Commons Math 3.6.1 API)

java.lang.Object
- org.apache.commons.math3.ode.AbstractIntegrator

All Implemented Interfaces:

FirstOrderIntegrator, ODEIntegrator

Direct Known Subclasses:

AdaptiveStepsizeIntegrator, RungeKuttaIntegrator
```
public abstract class AbstractIntegrator
extends Object
implements FirstOrderIntegrator
```
Base class managing common boilerplate for all integrators.

Since:

2.0

Field Summary

Fields
Modifier and Type	Field and Description
`protected boolean`	`isLastStep` Indicator for last step.
`protected boolean`	`resetOccurred` Indicator that a state or derivative reset was triggered by some event.
`protected Collection<StepHandler>`	`stepHandlers` Step handler.
`protected double`	`stepSize` Current stepsize.
`protected double`	`stepStart` Current step start time.

Constructor Summary

Constructors
Modifier Constructor and Description

protected AbstractIntegrator()
Build an instance with a null name.

AbstractIntegrator(String name)
Build an instance.

Constructors
Modifier	Constructor and Description
`protected`	`AbstractIntegrator()` Build an instance with a null name.
	`AbstractIntegrator(String name)` Build an instance.

Method Summary

Methods
Modifier and Type	Method and Description
`protected double`	`acceptStep(AbstractStepInterpolator interpolator, double[] y, double[] yDot, double tEnd)` Accept a step, triggering events and step handlers.
`void`	`addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount)` Add an event handler to the integrator.
`void`	`addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, UnivariateSolver solver)` Add an event handler to the integrator.
`void`	`addStepHandler(StepHandler 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.
`void`	`computeDerivatives(double t, double[] y, double[] yDot)` Compute the derivatives and check the number of evaluations.
`protected IntegerSequence.Incrementor`	`getCounter()` Get the evaluations counter.
`double`	`getCurrentSignedStepsize()` Get the current signed value of the integration stepsize.
`double`	`getCurrentStepStart()` Get the current value of the step start time t_i.
`int`	`getEvaluations()` Get the number of evaluations of the differential equations function.
`protected Incrementor`	`getEvaluationsCounter()` Deprecated. as of 3.6 replaced with `getCounter()`
`Collection<EventHandler>`	`getEventHandlers()` Get all the event handlers that have been added to the integrator.
`protected ExpandableStatefulODE`	`getExpandable()` Get the differential equations to integrate.
`int`	`getMaxEvaluations()` Get the maximal number of functions evaluations.
`String`	`getName()` Get the name of the method.
`Collection<StepHandler>`	`getStepHandlers()` Get all the step handlers that have been added to the integrator.
`protected void`	`initIntegration(double t0, double[] y0, double t)` Prepare the start of an integration.
`abstract void`	`integrate(ExpandableStatefulODE equations, double t)` Integrate a set of differential equations up to the given time.
`double`	`integrate(FirstOrderDifferentialEquations equations, double t0, double[] y0, double t, double[] y)` Integrate the differential equations up to the given time.
`protected void`	`sanityChecks(ExpandableStatefulODE equations, double t)` Check the integration span.
`protected void`	`setEquations(ExpandableStatefulODE equations)` Set the equations.
`void`	`setMaxEvaluations(int maxEvaluations)` Set the maximal number of differential equations function evaluations.
`protected void`	`setStateInitialized(boolean stateInitialized)` Set the stateInitialized flag.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - stepHandlers
```
protected Collection<StepHandler> stepHandlers
```
    Step handler.
  - stepStart
```
protected double stepStart
```
    Current step start time.
  - stepSize
```
protected double stepSize
```
    Current stepsize.
  - isLastStep
```
protected boolean isLastStep
```
    Indicator for last step.
  - resetOccurred
```
protected boolean resetOccurred
```
    Indicator that a state or derivative reset was triggered by some event.
- Constructor Detail
  - AbstractIntegrator
```
public AbstractIntegrator(String name)
```
    Build an instance.
    
    Parameters:
    name - name of the method
  - AbstractIntegrator
```
protected AbstractIntegrator()
```
    Build an instance with a null name.
- Method Detail
  - getName
```
public String getName()
```
    Get the name of the method.
    
    Specified by:
    
    getName in interface ODEIntegrator
    
    Returns:
    name of the method
  - addStepHandler
```
public void addStepHandler(StepHandler 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
    See Also:
    ODEIntegrator.getStepHandlers(), ODEIntegrator.clearStepHandlers()
  - getStepHandlers
```
public Collection<StepHandler> getStepHandlers()
```
    Get all the step handlers that have been added to the integrator.
    
    Specified by:
    
    getStepHandlers in interface ODEIntegrator
    
    Returns:
    an unmodifiable collection of the added events handlers
    See Also:
    ODEIntegrator.addStepHandler(StepHandler), ODEIntegrator.clearStepHandlers()
  - clearStepHandlers
```
public void clearStepHandlers()
```
    Remove all the step handlers that have been added to the integrator.
    
    Specified by:
    
    clearStepHandlers in interface ODEIntegrator
    
    See Also:
    ODEIntegrator.addStepHandler(StepHandler), ODEIntegrator.getStepHandlers()
  - addEventHandler
```
public void addEventHandler(EventHandler 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
    maxIterationCount - upper limit of the iteration count in the event time search
    See Also:
    ODEIntegrator.getEventHandlers(), ODEIntegrator.clearEventHandlers()
  - addEventHandler
```
public void addEventHandler(EventHandler handler,
                   double maxCheckInterval,
                   double convergence,
                   int maxIterationCount,
                   UnivariateSolver 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
    maxIterationCount - upper limit of the iteration count in the event time search
    solver - The root-finding algorithm to use to detect the state events.
    See Also:
    ODEIntegrator.getEventHandlers(), ODEIntegrator.clearEventHandlers()
  - getEventHandlers
```
public Collection<EventHandler> getEventHandlers()
```
    Get all the event handlers that have been added to the integrator.
    
    Specified by:
    
    getEventHandlers in interface ODEIntegrator
    
    Returns:
    an unmodifiable collection of the added events handlers
    See Also:
    ODEIntegrator.addEventHandler(EventHandler, double, double, int), ODEIntegrator.clearEventHandlers()
  - clearEventHandlers
```
public void clearEventHandlers()
```
    Remove all the event handlers that have been added to the integrator.
    
    Specified by:
    
    clearEventHandlers in interface ODEIntegrator
    
    See Also:
    ODEIntegrator.addEventHandler(EventHandler, double, double, int), ODEIntegrator.getEventHandlers()
  - getCurrentStepStart
```
public double 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.
    
    Specified by:
    
    getCurrentStepStart in interface ODEIntegrator
    
    Returns:
    current value of the step start time t_i
  - 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 void initIntegration(double t0,
                   double[] y0,
                   double t)
```
    Prepare the start of an integration.
    
    Parameters:
    t0 - start value of the independent time variable
    y0 - array containing the start value of the state vector
    t - target time for the integration
  - setEquations
```
protected void setEquations(ExpandableStatefulODE equations)
```
    Set the equations.
    
    Parameters:
    equations - equations to set
  - getExpandable
```
protected ExpandableStatefulODE getExpandable()
```
    Get the differential equations to integrate.
    
    Returns:
    differential equations to integrate
    Since:
    
    3.2
  - getEvaluationsCounter
```
@Deprecated
protected Incrementor getEvaluationsCounter()
```
    Deprecated. as of 3.6 replaced with getCounter()
    
    Get the evaluations counter.
    
    Returns:
    evaluations counter
    Since:
    
    3.2
  - getCounter
```
protected IntegerSequence.Incrementor getCounter()
```
    Get the evaluations counter.
    
    Returns:
    evaluations counter
    Since:
    
    3.6
  - integrate
```
public double integrate(FirstOrderDifferentialEquations equations,
               double t0,
               double[] y0,
               double t,
               double[] y)
                 throws DimensionMismatchException,
                        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 (ODEIntegrator.getCurrentSignedStepsize()), it is not thread-safe.
    
    Specified by:
    
    integrate in interface FirstOrderIntegrator
    
    Parameters:
    equations - differential equations to integrate
    t0 - initial time
    y0 - initial value of the state vector at t0
    t - target time for the integration (can be set to a value smaller than t0 for backward integration)
    y - placeholder where to put the state vector at each successful step (and hence at the end of integration), can be the same object as y0
    
    Returns:
    stop time, will be the same as target time if integration reached its target, but may be different if some EventHandler stops it at some point.
    
    Throws:
    
    DimensionMismatchException - if arrays dimension do not match equations settings
    
    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
  - integrate
```
public abstract void integrate(ExpandableStatefulODE equations,
             double t)
                        throws NumberIsTooSmallException,
                               DimensionMismatchException,
                               MaxCountExceededException,
                               NoBracketingException
```
    Integrate a set of differential equations up to the given time.
    This method solves an Initial Value Problem (IVP).
    
    The set of differential equations is composed of a main set, which can be extended by some sets of secondary equations. The set of equations must be already set up with initial time and partial states. At integration completion, the final time and partial states will be available in the same object.
    
    Since this method stores some internal state variables made available in its public interface during integration (getCurrentSignedStepsize()), it is not thread-safe.
    
    Parameters:
    equations - complete set of differential equations to integrate
    t - target time for the integration (can be set to a value smaller than t0 for backward integration)
    
    Throws:
    
    NumberIsTooSmallException - if integration step is too small
    
    DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension
    
    MaxCountExceededException - if the number of functions evaluations is exceeded
    
    NoBracketingException - if the location of an event cannot be bracketed
  - computeDerivatives
```
public void computeDerivatives(double t,
                      double[] y,
                      double[] yDot)
                        throws MaxCountExceededException,
                               DimensionMismatchException,
                               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
    yDot - placeholder array where to put the time derivative of the state vector
    
    Throws:
    
    MaxCountExceededException - if the number of functions evaluations is exceeded
    
    DimensionMismatchException - if arrays dimensions do not match equations settings
    
    NullPointerException - if the ODE equations have not been set (i.e. if this method is called outside of a call to integrate(ExpandableStatefulODE, double) or integrate(FirstOrderDifferentialEquations, double, double[], double, double[]))
  - 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
    Since:
    
    2.2
  - acceptStep
```
protected double acceptStep(AbstractStepInterpolator interpolator,
                double[] y,
                double[] yDot,
                double tEnd)
                     throws MaxCountExceededException,
                            DimensionMismatchException,
                            NoBracketingException
```
    Accept a step, triggering events and step handlers.
    
    Parameters:
    interpolator - step interpolator
    y - state vector at step end time, must be reset if an event asks for resetting or if an events stops integration during the step
    yDot - placeholder array where to put the time derivative of the state vector
    tEnd - final integration time
    
    Returns:
    time at end of step
    
    Throws:
    
    MaxCountExceededException - if the interpolator throws one because the number of functions evaluations is exceeded
    
    NoBracketingException - if the location of an event cannot be bracketed
    
    DimensionMismatchException - if arrays dimensions do not match equations settings
    Since:
    
    2.2
  - sanityChecks
```
protected void sanityChecks(ExpandableStatefulODE equations,
                double t)
                     throws NumberIsTooSmallException,
                            DimensionMismatchException
```
    Check the integration span.
    
    Parameters:
    equations - set of differential equations
    t - target time for the integration
    
    Throws:
    
    NumberIsTooSmallException - if integration span is too small
    
    DimensionMismatchException - if adaptive step size integrators tolerance arrays dimensions are not compatible with equations settings

Class AbstractIntegrator

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

stepHandlers

stepStart

stepSize

isLastStep

resetOccurred

Constructor Detail

AbstractIntegrator

AbstractIntegrator

Method Detail

getName

addStepHandler

getStepHandlers

clearStepHandlers

addEventHandler

addEventHandler

getEventHandlers

clearEventHandlers

getCurrentStepStart

getCurrentSignedStepsize

setMaxEvaluations

getMaxEvaluations

getEvaluations

initIntegration

setEquations

getExpandable

getEvaluationsCounter

getCounter

integrate

integrate

computeDerivatives

setStateInitialized

acceptStep

sanityChecks