org.apache.commons.math3.ode
public abstract class AbstractIntegrator extends Object implements FirstOrderIntegrator
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.

Modifier  Constructor and Description 

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


AbstractIntegrator(String name)
Build an instance.

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.

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()
Get the evaluations counter.

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.

protected Collection<StepHandler> stepHandlers
protected double stepStart
protected double stepSize
protected boolean isLastStep
protected boolean resetOccurred
public AbstractIntegrator(String name)
name
 name of the methodprotected AbstractIntegrator()
public String getName()
getName
in interface ODEIntegrator
public void addStepHandler(StepHandler handler)
The handler will be called by the integrator for each accepted step.
addStepHandler
in interface ODEIntegrator
handler
 handler for the accepted stepsODEIntegrator.getStepHandlers()
,
ODEIntegrator.clearStepHandlers()
public Collection<StepHandler> getStepHandlers()
getStepHandlers
in interface ODEIntegrator
ODEIntegrator.addStepHandler(StepHandler)
,
ODEIntegrator.clearStepHandlers()
public void clearStepHandlers()
clearStepHandlers
in interface ODEIntegrator
ODEIntegrator.addStepHandler(StepHandler)
,
ODEIntegrator.getStepHandlers()
public void addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount)
UnivariateSolver
with an absolute accuracy equal to the given convergence threshold,
as rootfinding algorithm to detect the state events.addEventHandler
in interface ODEIntegrator
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 searchODEIntegrator.getEventHandlers()
,
ODEIntegrator.clearEventHandlers()
public void addEventHandler(EventHandler handler, double maxCheckInterval, double convergence, int maxIterationCount, UnivariateSolver solver)
addEventHandler
in interface ODEIntegrator
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 rootfinding algorithm to use to detect the state
events.ODEIntegrator.getEventHandlers()
,
ODEIntegrator.clearEventHandlers()
public Collection<EventHandler> getEventHandlers()
getEventHandlers
in interface ODEIntegrator
ODEIntegrator.addEventHandler(EventHandler, double, double, int)
,
ODEIntegrator.clearEventHandlers()
public void clearEventHandlers()
clearEventHandlers
in interface ODEIntegrator
ODEIntegrator.addEventHandler(EventHandler, double, double, int)
,
ODEIntegrator.getEventHandlers()
public double getCurrentStepStart()
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
.
getCurrentStepStart
in interface ODEIntegrator
public double getCurrentSignedStepsize()
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
.
getCurrentSignedStepsize
in interface ODEIntegrator
public void setMaxEvaluations(int maxEvaluations)
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.
setMaxEvaluations
in interface ODEIntegrator
maxEvaluations
 maximal number of function evaluations (negative
values are silently converted to maximal integer value, thus representing
almost unlimited evaluations)public int getMaxEvaluations()
getMaxEvaluations
in interface ODEIntegrator
public int getEvaluations()
The number of evaluations corresponds to the last call to the
integrate
method. It is 0 if the method has not been called yet.
getEvaluations
in interface ODEIntegrator
protected void initIntegration(double t0, double[] y0, double t)
t0
 start value of the independent time variabley0
 array containing the start value of the state vectort
 target time for the integrationprotected void setEquations(ExpandableStatefulODE equations)
equations
 equations to setprotected ExpandableStatefulODE getExpandable()
protected Incrementor getEvaluationsCounter()
public double integrate(FirstOrderDifferentialEquations equations, double t0, double[] y0, double t, double[] y) throws DimensionMismatchException, NumberIsTooSmallException, MaxCountExceededException, NoBracketingException
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 threadsafe.
integrate
in interface FirstOrderIntegrator
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 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 y0EventHandler
stops it at some point.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 bracketedpublic abstract void integrate(ExpandableStatefulODE equations, double t) throws NumberIsTooSmallException, DimensionMismatchException, MaxCountExceededException, NoBracketingException
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 threadsafe.
equations
 complete set of differential equations to integratet
 target time for the integration
(can be set to a value smaller than t0
for backward integration)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 bracketedpublic void computeDerivatives(double t, double[] y, double[] yDot) throws MaxCountExceededException, DimensionMismatchException
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 vectorMaxCountExceededException
 if the number of functions evaluations is exceededDimensionMismatchException
 if arrays dimensions do not match equations settingsprotected void setStateInitialized(boolean stateInitialized)
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.
stateInitialized
 new value for the flagprotected double acceptStep(AbstractStepInterpolator interpolator, double[] y, double[] yDot, double tEnd) throws MaxCountExceededException, DimensionMismatchException, NoBracketingException
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 timeMaxCountExceededException
 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 settingsprotected void sanityChecks(ExpandableStatefulODE equations, double t) throws NumberIsTooSmallException, DimensionMismatchException
equations
 set of differential equationst
 target time for the integrationNumberIsTooSmallException
 if integration span is too smallDimensionMismatchException
 if adaptive step size integrators
tolerance arrays dimensions are not compatible with equations settingsCopyright © 2003–2015 The Apache Software Foundation. All rights reserved.