Class AbstractIntegrator
- java.lang.Object
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- org.apache.commons.math4.legacy.ode.AbstractIntegrator
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- 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
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Field Summary
Fields Modifier and Type Field Description protected booleanisLastStepIndicator for last step.protected booleanresetOccurredIndicator that a state or derivative reset was triggered by some event.protected Collection<StepHandler>stepHandlersStep handler.protected doublestepSizeCurrent stepsize.protected doublestepStartCurrent step start time.
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Constructor Summary
Constructors Modifier Constructor Description protectedAbstractIntegrator()Build an instance with a null name.AbstractIntegrator(String name)Build an instance.
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Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected doubleacceptStep(AbstractStepInterpolator interpolator, double[] y, double[] yDot, double tEnd)Accept a step, triggering events and step handlers.voidaddEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount)Add an event handler to the integrator.voidaddEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, UnivariateSolver solver)Add an event handler to the integrator.voidaddStepHandler(StepHandler handler)Add a step handler to this integrator.voidclearEventHandlers()Remove all the event handlers that have been added to the integrator.voidclearStepHandlers()Remove all the step handlers that have been added to the integrator.voidcomputeDerivatives(double t, double[] y, double[] yDot)Compute the derivatives and check the number of evaluations.protected IntegerSequence.IncrementorgetCounter()Get the evaluations counter.doublegetCurrentSignedStepsize()Get the current signed value of the integration stepsize.doublegetCurrentStepStart()Get the current value of the step start time ti.intgetEvaluations()Get the number of evaluations of the differential equations function.Collection<EventHandler>getEventHandlers()Get all the event handlers that have been added to the integrator.protected ExpandableStatefulODEgetExpandable()Get the differential equations to integrate.intgetMaxEvaluations()Get the maximal number of functions evaluations.StringgetName()Get the name of the method.Collection<StepHandler>getStepHandlers()Get all the step handlers that have been added to the integrator.protected voidinitIntegration(double t0, double[] y0, double t)Prepare the start of an integration.abstract voidintegrate(ExpandableStatefulODE equations, double t)Integrate a set of differential equations up to the given time.doubleintegrate(FirstOrderDifferentialEquations equations, double t0, double[] y0, double t, double[] y)Integrate the differential equations up to the given time.protected voidsanityChecks(ExpandableStatefulODE equations, double t)Check the integration span.protected voidsetEquations(ExpandableStatefulODE equations)Set the equations.voidsetMaxEvaluations(int maxEvaluations)Set the maximal number of differential equations function evaluations.protected voidsetStateInitialized(boolean stateInitialized)Set the stateInitialized flag.
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Field Detail
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stepHandlers
protected Collection<StepHandler> stepHandlers
Step handler.
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stepStart
protected double stepStart
Current step start time.
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stepSize
protected double stepSize
Current stepsize.
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isLastStep
protected boolean isLastStep
Indicator for last step.
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resetOccurred
protected boolean resetOccurred
Indicator that a state or derivative reset was triggered by some event.
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Constructor Detail
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AbstractIntegrator
public AbstractIntegrator(String name)
Build an instance.- Parameters:
name- name of the method
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AbstractIntegrator
protected AbstractIntegrator()
Build an instance with a null name.
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Method Detail
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getName
public String getName()
Get the name of the method.- Specified by:
getNamein interfaceODEIntegrator- Returns:
- name of the method
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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:
addStepHandlerin interfaceODEIntegrator- Parameters:
handler- handler for the accepted steps- See Also:
ODEIntegrator.getStepHandlers(),ODEIntegrator.clearStepHandlers()
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getStepHandlers
public Collection<StepHandler> getStepHandlers()
Get all the step handlers that have been added to the integrator.- Specified by:
getStepHandlersin interfaceODEIntegrator- Returns:
- an unmodifiable collection of the added events handlers
- See Also:
ODEIntegrator.addStepHandler(StepHandler),ODEIntegrator.clearStepHandlers()
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clearStepHandlers
public void clearStepHandlers()
Remove all the step handlers that have been added to the integrator.- Specified by:
clearStepHandlersin interfaceODEIntegrator- See Also:
ODEIntegrator.addStepHandler(StepHandler),ODEIntegrator.getStepHandlers()
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addEventHandler
public void addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount)
Add an event handler to the integrator. Uses a defaultUnivariateSolverwith an absolute accuracy equal to the given convergence threshold, as root-finding algorithm to detect the state events.- Specified by:
addEventHandlerin interfaceODEIntegrator- Parameters:
handler- event handlermaxCheckInterval- 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 searchmaxIterationCount- upper limit of the iteration count in the event time search- See Also:
ODEIntegrator.getEventHandlers(),ODEIntegrator.clearEventHandlers()
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addEventHandler
public void addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, UnivariateSolver solver)
Add an event handler to the integrator.- Specified by:
addEventHandlerin interfaceODEIntegrator- Parameters:
handler- event handlermaxCheckInterval- 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 searchmaxIterationCount- upper limit of the iteration count in the event time searchsolver- The root-finding algorithm to use to detect the state events.- See Also:
ODEIntegrator.getEventHandlers(),ODEIntegrator.clearEventHandlers()
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getEventHandlers
public Collection<EventHandler> getEventHandlers()
Get all the event handlers that have been added to the integrator.- Specified by:
getEventHandlersin interfaceODEIntegrator- Returns:
- an unmodifiable collection of the added events handlers
- See Also:
ODEIntegrator.addEventHandler(EventHandler, double, double, int),ODEIntegrator.clearEventHandlers()
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clearEventHandlers
public void clearEventHandlers()
Remove all the event handlers that have been added to the integrator.- Specified by:
clearEventHandlersin interfaceODEIntegrator- See Also:
ODEIntegrator.addEventHandler(EventHandler, double, double, int),ODEIntegrator.getEventHandlers()
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getCurrentStepStart
public double getCurrentStepStart()
Get the current value of the step start time ti.This method can be called during integration (typically by the object implementing the
differential equationsproblem) 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:
getCurrentStepStartin interfaceODEIntegrator- Returns:
- current value of the step start time ti
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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 equationsproblem) 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:
getCurrentSignedStepsizein interfaceODEIntegrator- Returns:
- current signed value of the stepsize
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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:
setMaxEvaluationsin interfaceODEIntegrator- Parameters:
maxEvaluations- maximal number of function evaluations (negative values are silently converted to maximal integer value, thus representing almost unlimited evaluations)
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getMaxEvaluations
public int getMaxEvaluations()
Get the maximal number of functions evaluations.- Specified by:
getMaxEvaluationsin interfaceODEIntegrator- Returns:
- maximal number of functions evaluations
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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
integratemethod. It is 0 if the method has not been called yet.- Specified by:
getEvaluationsin interfaceODEIntegrator- Returns:
- number of evaluations of the differential equations function
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initIntegration
protected void initIntegration(double t0, double[] y0, double t)
Prepare the start of an integration.- Parameters:
t0- start value of the independent time variabley0- array containing the start value of the state vectort- target time for the integration
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setEquations
protected void setEquations(ExpandableStatefulODE equations)
Set the equations.- Parameters:
equations- equations to set
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getExpandable
protected ExpandableStatefulODE getExpandable()
Get the differential equations to integrate.- Returns:
- differential equations to integrate
- Since:
- 3.2
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getCounter
protected IntegerSequence.Incrementor getCounter()
Get the evaluations counter.- Returns:
- evaluations counter
- Since:
- 3.6
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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:
integratein interfaceFirstOrderIntegrator- Parameters:
equations- differential equations to integratet0- initial timey0- initial value of the state vector at t0t- target time for the integration (can be set to a value smaller thant0for 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
EventHandlerstops it at some point. - Throws:
DimensionMismatchException- if arrays dimension do not match equations settingsNumberIsTooSmallException- if integration step is too smallMaxCountExceededException- if the number of functions evaluations is exceededNoBracketingException- if the location of an event cannot be bracketed
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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 integratet- target time for the integration (can be set to a value smaller thant0for backward integration)- Throws:
NumberIsTooSmallException- if integration step is too smallDimensionMismatchException- if the dimension of the complete state does not match the complete equations sets dimensionMaxCountExceededException- if the number of functions evaluations is exceededNoBracketingException- if the location of an event cannot be bracketed
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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 variabley- array containing the current value of the state vectoryDot- placeholder array where to put the time derivative of the state vector- Throws:
MaxCountExceededException- if the number of functions evaluations is exceededDimensionMismatchException- if arrays dimensions do not match equations settingsNullPointerException- if the ODE equations have not been set (i.e. if this method is called outside of a call tointegrate(ExpandableStatefulODE, double)orintegrate(FirstOrderDifferentialEquations, double, double[], double, double[]))
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setStateInitialized
protected void setStateInitialized(boolean stateInitialized)
Set the stateInitialized flag.This method must be called by integrators with the value
falsebefore 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
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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 interpolatory- state vector at step end time, must be reset if an event asks for resetting or if an events stops integration during the stepyDot- placeholder array where to put the time derivative of the state vectortEnd- final integration time- Returns:
- time at end of step
- Throws:
MaxCountExceededException- if the interpolator throws one because the number of functions evaluations is exceededNoBracketingException- if the location of an event cannot be bracketedDimensionMismatchException- if arrays dimensions do not match equations settings- Since:
- 2.2
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sanityChecks
protected void sanityChecks(ExpandableStatefulODE equations, double t) throws NumberIsTooSmallException, DimensionMismatchException
Check the integration span.- Parameters:
equations- set of differential equationst- target time for the integration- Throws:
NumberIsTooSmallException- if integration span is too smallDimensionMismatchException- if adaptive step size integrators tolerance arrays dimensions are not compatible with equations settings
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