Package org.apache.commons.math3.ode.nonstiff

Class DormandPrince54StepInterpolator

java.lang.Object

org.apache.commons.math3.ode.sampling.AbstractStepInterpolator

org.apache.commons.math3.ode.nonstiff.RungeKuttaStepInterpolator

org.apache.commons.math3.ode.nonstiff.DormandPrince54StepInterpolator

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, StepInterpolator

class DormandPrince54StepInterpolator
extends RungeKuttaStepInterpolator

This class represents an interpolator over the last step during an ODE integration for the 5(4) Dormand-Prince integrator.

Since:

1.2

See Also:

DormandPrince54Integrator

Field Summary

Fields

Modifier and Type	Field	Description
private static double	A70	Last row of the Butcher-array internal weights, element 0.
private static double	A72	Last row of the Butcher-array internal weights, element 2.
private static double	A73	Last row of the Butcher-array internal weights, element 3.
private static double	A74	Last row of the Butcher-array internal weights, element 4.
private static double	A75	Last row of the Butcher-array internal weights, element 5.
private static double	D0	Shampine (1986) Dense output, element 0.
private static double	D2	Shampine (1986) Dense output, element 2.
private static double	D3	Shampine (1986) Dense output, element 3.
private static double	D4	Shampine (1986) Dense output, element 4.
private static double	D5	Shampine (1986) Dense output, element 5.
private static double	D6	Shampine (1986) Dense output, element 6.
private static long	serialVersionUID	Serializable version identifier.
private double[]	v1	First vector for interpolation.
private double[]	v2	Second vector for interpolation.
private double[]	v3	Third vector for interpolation.
private double[]	v4	Fourth vector for interpolation.
private boolean	vectorsInitialized	Initialization indicator for the interpolation vectors.

Fields inherited from class org.apache.commons.math3.ode.nonstiff.RungeKuttaStepInterpolator

integrator, previousState, yDotK

Fields inherited from class org.apache.commons.math3.ode.sampling.AbstractStepInterpolator

currentState, h, interpolatedDerivatives, interpolatedPrimaryDerivatives, interpolatedPrimaryState, interpolatedSecondaryDerivatives, interpolatedSecondaryState, interpolatedState, interpolatedTime

Constructor Summary

Constructors

Constructor	Description
DormandPrince54StepInterpolator()	Simple constructor.
DormandPrince54StepInterpolator(DormandPrince54StepInterpolator interpolator)	Copy constructor.

Method Summary

Modifier and Type	Method	Description
protected void	computeInterpolatedStateAndDerivatives(double theta, double oneMinusThetaH)	Compute the state and derivatives at the interpolated time.
protected StepInterpolator	doCopy()	Really copy the finalized instance.
void	reinitialize(AbstractIntegrator integrator, double[] y, double[][] yDotK, boolean forward, EquationsMapper primaryMapper, EquationsMapper[] secondaryMappers)	Reinitialize the instance
void	storeTime(double t)	Store the current step time.

Methods inherited from class org.apache.commons.math3.ode.nonstiff.RungeKuttaStepInterpolator

readExternal, shift, writeExternal

Methods inherited from class org.apache.commons.math3.ode.sampling.AbstractStepInterpolator

copy, doFinalize, finalizeStep, getCurrentTime, getGlobalCurrentTime, getGlobalPreviousTime, getInterpolatedDerivatives, getInterpolatedSecondaryDerivatives, getInterpolatedSecondaryState, getInterpolatedState, getInterpolatedTime, getPreviousTime, isForward, readBaseExternal, reinitialize, setInterpolatedTime, setSoftCurrentTime, setSoftPreviousTime, writeBaseExternal

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

A70

private static final double A70

Last row of the Butcher-array internal weights, element 0.

See Also:

Constant Field Values

A72

private static final double A72

Last row of the Butcher-array internal weights, element 2.

See Also:

Constant Field Values

A73

private static final double A73

Last row of the Butcher-array internal weights, element 3.

See Also:

Constant Field Values

A74

private static final double A74

Last row of the Butcher-array internal weights, element 4.

See Also:

Constant Field Values

A75

private static final double A75

Last row of the Butcher-array internal weights, element 5.

See Also:

Constant Field Values

D0

private static final double D0

Shampine (1986) Dense output, element 0.

See Also:

Constant Field Values

D2

private static final double D2

Shampine (1986) Dense output, element 2.

See Also:

Constant Field Values

D3

private static final double D3

Shampine (1986) Dense output, element 3.

See Also:

Constant Field Values

D4

private static final double D4

Shampine (1986) Dense output, element 4.

See Also:

Constant Field Values

D5

private static final double D5

Shampine (1986) Dense output, element 5.

See Also:

Constant Field Values

D6

private static final double D6

Shampine (1986) Dense output, element 6.

See Also:

Constant Field Values

serialVersionUID

private static final long serialVersionUID

Serializable version identifier.

See Also:

Constant Field Values

v1

private double[] v1

First vector for interpolation.

v2

private double[] v2

Second vector for interpolation.

v3

private double[] v3

Third vector for interpolation.

v4

private double[] v4

Fourth vector for interpolation.

vectorsInitialized

private boolean vectorsInitialized

Initialization indicator for the interpolation vectors.

Constructor Detail

DormandPrince54StepInterpolator

public DormandPrince54StepInterpolator()

Simple constructor. This constructor builds an instance that is not usable yet, the reinitialize(org.apache.commons.math3.ode.AbstractIntegrator, double[], double[][], boolean, org.apache.commons.math3.ode.EquationsMapper, org.apache.commons.math3.ode.EquationsMapper[]) method should be called before using the instance in order to initialize the internal arrays. This constructor is used only in order to delay the initialization in some cases. The EmbeddedRungeKuttaIntegrator uses the prototyping design pattern to create the step interpolators by cloning an uninitialized model and latter initializing the copy.

DormandPrince54StepInterpolator

DormandPrince54StepInterpolator(DormandPrince54StepInterpolator interpolator)

Copy constructor.

Parameters:

interpolator - interpolator to copy from. The copy is a deep copy: its arrays are separated from the original arrays of the instance

Method Detail

doCopy

protected StepInterpolator doCopy()

Really copy the finalized instance.

This method is called by AbstractStepInterpolator.copy() after the step has been finalized. It must perform a deep copy to have an new instance completely independent for the original instance.

Specified by:

doCopy in class AbstractStepInterpolator

Returns:

a copy of the finalized instance

reinitialize

public void reinitialize(AbstractIntegrator integrator,
                         double[] y,
                         double[][] yDotK,
                         boolean forward,
                         EquationsMapper primaryMapper,
                         EquationsMapper[] secondaryMappers)

Reinitialize the instance

Some Runge-Kutta integrators need fewer functions evaluations than their counterpart step interpolators. So the interpolator should perform the last evaluations they need by themselves. The RungeKuttaIntegrator and EmbeddedRungeKuttaIntegrator abstract classes call this method in order to let the step interpolator perform the evaluations it needs. These evaluations will be performed during the call to doFinalize if any, i.e. only if the step handler either calls the finalizeStep method or the getInterpolatedState method (for an interpolator which needs a finalization) or if it clones the step interpolator.

Overrides:

reinitialize in class RungeKuttaStepInterpolator

Parameters:

integrator - integrator being used

y - reference to the integrator array holding the state at the end of the step

yDotK - reference to the integrator array holding all the intermediate slopes

forward - integration direction indicator

primaryMapper - equations mapper for the primary equations set

secondaryMappers - equations mappers for the secondary equations sets

storeTime

public void storeTime(double t)

Store the current step time.

Overrides:

storeTime in class AbstractStepInterpolator

Parameters:

t - current time

computeInterpolatedStateAndDerivatives

protected void computeInterpolatedStateAndDerivatives(double theta,
                                                      double oneMinusThetaH)

Compute the state and derivatives at the interpolated time. This is the main processing method that should be implemented by the derived classes to perform the interpolation.

Specified by:

computeInterpolatedStateAndDerivatives in class AbstractStepInterpolator

Parameters:

theta - normalized interpolation abscissa within the step (theta is zero at the previous time step and one at the current time step)

oneMinusThetaH - time gap between the interpolated time and the current time