org.apache.commons.math4.ode.nonstiff

• ### Fields inherited from class org.apache.commons.math4.ode.MultistepFieldIntegrator

nordsieck, scaled
• ### Fields inherited from class org.apache.commons.math4.ode.nonstiff.AdaptiveStepsizeFieldIntegrator

mainSetDimension, scalAbsoluteTolerance, scalRelativeTolerance, vecAbsoluteTolerance, vecRelativeTolerance
• ### Constructor Summary

Constructors
Constructor and Description
AdamsFieldIntegrator(Field<T> field, String name, int nSteps, int order, double minStep, double maxStep, double[] vecAbsoluteTolerance, double[] vecRelativeTolerance)
Build an Adams integrator with the given order and step control parameters.
AdamsFieldIntegrator(Field<T> field, String name, int nSteps, int order, double minStep, double maxStep, double scalAbsoluteTolerance, double scalRelativeTolerance)
Build an Adams integrator with the given order and step control parameters.
• ### Method Summary

All Methods
Modifier and Type Method and Description
protected Array2DRowFieldMatrix<T> initializeHighOrderDerivatives(T h, T[] t, T[][] y, T[][] yDot)
Initialize the high order scaled derivatives at step start.
abstract FieldODEStateAndDerivative<T> integrate(FieldExpandableODE<T> equations, FieldODEState<T> initialState, T finalTime)
Integrate the differential equations up to the given time.
Array2DRowFieldMatrix<T> updateHighOrderDerivativesPhase1(Array2DRowFieldMatrix<T> highOrder)
Update the high order scaled derivatives for Adams integrators (phase 1).
void updateHighOrderDerivativesPhase2(T[] start, T[] end, Array2DRowFieldMatrix<T> highOrder)
Update the high order scaled derivatives Adams integrators (phase 2).
• ### Methods inherited from class org.apache.commons.math4.ode.MultistepFieldIntegrator

computeStepGrowShrinkFactor, getMaxGrowth, getMinReduction, getNSteps, getSafety, getStarterIntegrator, rescale, setMaxGrowth, setMinReduction, setSafety, setStarterIntegrator, start
• ### Methods inherited from class org.apache.commons.math4.ode.nonstiff.AdaptiveStepsizeFieldIntegrator

filterStep, getMaxStep, getMinStep, initializeStep, resetInternalState, sanityChecks, setInitialStepSize, setStepSizeControl, setStepSizeControl
• ### Methods inherited from class org.apache.commons.math4.ode.AbstractFieldIntegrator

acceptStep, addEventHandler, addEventHandler, addStepHandler, clearEventHandlers, clearStepHandlers, computeDerivatives, getCurrentSignedStepsize, getCurrentStepStart, getEquations, getEvaluations, getEvaluationsCounter, getEventHandlers, getField, getMaxEvaluations, getName, getStepHandlers, getStepSize, getStepStart, initIntegration, isLastStep, resetOccurred, setIsLastStep, setMaxEvaluations, setStateInitialized, setStepSize, setStepStart
• ### Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
• ### Constructor Detail

public AdamsFieldIntegrator(Field<T> field,
String name,
int nSteps,
int order,
double minStep,
double maxStep,
double scalAbsoluteTolerance,
double scalRelativeTolerance)
throws NumberIsTooSmallException
Build an Adams integrator with the given order and step control parameters.
Parameters:
field - field to which the time and state vector elements belong
name - name of the method
nSteps - number of steps of the method excluding the one being computed
order - order of the method
minStep - minimal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
maxStep - maximal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
scalAbsoluteTolerance - allowed absolute error
scalRelativeTolerance - allowed relative error
Throws:
NumberIsTooSmallException - if order is 1 or less

public AdamsFieldIntegrator(Field<T> field,
String name,
int nSteps,
int order,
double minStep,
double maxStep,
double[] vecAbsoluteTolerance,
double[] vecRelativeTolerance)
throws IllegalArgumentException
Build an Adams integrator with the given order and step control parameters.
Parameters:
field - field to which the time and state vector elements belong
name - name of the method
nSteps - number of steps of the method excluding the one being computed
order - order of the method
minStep - minimal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
maxStep - maximal step (sign is irrelevant, regardless of integration direction, forward or backward), the last step can be smaller than this
vecAbsoluteTolerance - allowed absolute error
vecRelativeTolerance - allowed relative error
Throws:
IllegalArgumentException - if order is 1 or less
• ### Method Detail

• #### integrate

public abstract FieldODEStateAndDerivative<T> integrate(FieldExpandableODE<T> equations,
FieldODEState<T> initialState,
T finalTime)
throws NumberIsTooSmallException,
DimensionMismatchException,
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 (FirstOrderFieldIntegrator.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 FieldEventHandler stops it at some point.
Throws:
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
DimensionMismatchException
• #### initializeHighOrderDerivatives

protected Array2DRowFieldMatrix<T> initializeHighOrderDerivatives(T h,
T[] t,
T[][] y,
T[][] yDot)
Initialize the high order scaled derivatives at step start.
Specified by:
initializeHighOrderDerivatives in class MultistepFieldIntegrator<T extends RealFieldElement<T>>
Parameters:
h - step size to use for scaling
t - first steps times
y - first steps states
yDot - first steps derivatives
Returns:
Nordieck vector at first step (h2/2 y''n, h3/6 y'''n ... hk/k! y(k)n)
• #### updateHighOrderDerivativesPhase1

public Array2DRowFieldMatrix<T> updateHighOrderDerivativesPhase1(Array2DRowFieldMatrix<T> highOrder)
Update the high order scaled derivatives for Adams integrators (phase 1).

The complete update of high order derivatives has a form similar to:

 rn+1 = (s1(n) - s1(n+1)) P-1 u + P-1 A P rn

this method computes the P-1 A P rn part.

Parameters:
highOrder - high order scaled derivatives (h2/2 y'', ... hk/k! y(k))
Returns:
updated high order derivatives
updateHighOrderDerivativesPhase2(RealFieldElement[], RealFieldElement[], Array2DRowFieldMatrix)
• #### updateHighOrderDerivativesPhase2

public void updateHighOrderDerivativesPhase2(T[] start,
T[] end,
Array2DRowFieldMatrix<T> highOrder)
Update the high order scaled derivatives Adams integrators (phase 2).

The complete update of high order derivatives has a form similar to:

 rn+1 = (s1(n) - s1(n+1)) P-1 u + P-1 A P rn

this method computes the (s1(n) - s1(n+1)) P-1 u part.

Phase 1 of the update must already have been performed.

Parameters:
start - first order scaled derivatives at step start
end - first order scaled derivatives at step end
highOrder - high order scaled derivatives, will be modified (h2/2 y'', ... hk/k! y(k))
updateHighOrderDerivativesPhase1(Array2DRowFieldMatrix)