Apache Commons Math 3.6.1 · org.apache.commons.math3.ode.sampling.FieldStepNormalizer

This class wraps an object implementing FieldFixedStepHandler into a FieldStepHandler.

This wrapper allows to use fixed step handlers with general integrators which cannot guaranty their integration steps will remain constant and therefore only accept general step handlers.

The stepsize used is selected at construction time. The handleStep method of the underlying FieldFixedStepHandler object is called at normalized times. The normalized times can be influenced by the StepNormalizerMode and StepNormalizerBounds.

There is no constraint on the integrator, it can use any time step it needs (time steps longer or shorter than the fixed time step and non-integer ratios are all allowed).

Examples (step size = 0.5)
Start time	End time	Direction	`Mode`	`Bounds`	Output
0.3	3.1	forward	`INCREMENT`	`NEITHER`	0.8, 1.3, 1.8, 2.3, 2.8
0.3	3.1	forward	`INCREMENT`	`FIRST`	0.3, 0.8, 1.3, 1.8, 2.3, 2.8
0.3	3.1	forward	`INCREMENT`	`LAST`	0.8, 1.3, 1.8, 2.3, 2.8, 3.1
0.3	3.1	forward	`INCREMENT`	`BOTH`	0.3, 0.8, 1.3, 1.8, 2.3, 2.8, 3.1
0.3	3.1	forward	`MULTIPLES`	`NEITHER`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.3	3.1	forward	`MULTIPLES`	`FIRST`	0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.3	3.1	forward	`MULTIPLES`	`LAST`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1
0.3	3.1	forward	`MULTIPLES`	`BOTH`	0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1
0.0	3.0	forward	`INCREMENT`	`NEITHER`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`INCREMENT`	`FIRST`	0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`INCREMENT`	`LAST`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`INCREMENT`	`BOTH`	0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`MULTIPLES`	`NEITHER`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`MULTIPLES`	`FIRST`	0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`MULTIPLES`	`LAST`	0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.0	3.0	forward	`MULTIPLES`	`BOTH`	0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
3.1	0.3	backward	`INCREMENT`	`NEITHER`	2.6, 2.1, 1.6, 1.1, 0.6
3.1	0.3	backward	`INCREMENT`	`FIRST`	3.1, 2.6, 2.1, 1.6, 1.1, 0.6
3.1	0.3	backward	`INCREMENT`	`LAST`	2.6, 2.1, 1.6, 1.1, 0.6, 0.3
3.1	0.3	backward	`INCREMENT`	`BOTH`	3.1, 2.6, 2.1, 1.6, 1.1, 0.6, 0.3
3.1	0.3	backward	`MULTIPLES`	`NEITHER`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5
3.1	0.3	backward	`MULTIPLES`	`FIRST`	3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5
3.1	0.3	backward	`MULTIPLES`	`LAST`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3
3.1	0.3	backward	`MULTIPLES`	`BOTH`	3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3
3.0	0.0	backward	`INCREMENT`	`NEITHER`	2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`INCREMENT`	`FIRST`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`INCREMENT`	`LAST`	2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`INCREMENT`	`BOTH`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`MULTIPLES`	`NEITHER`	2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`MULTIPLES`	`FIRST`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`MULTIPLES`	`LAST`	2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.0	0.0	backward	`MULTIPLES`	`BOTH`	3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0

Modifier and Type	Field and Description
private final StepNormalizerBounds	bounds The step normalizer bounds settings to use.
private FieldODEStateAndDerivative<T>	first First step state.
private boolean	forward Integration direction indicator.
private double	h Fixed time step.
private final FieldFixedStepHandler<T>	handler Underlying step handler.
private FieldODEStateAndDerivative<T>	last Last step step.
private final StepNormalizerMode	mode The step normalizer mode to use.

Access	Constructor and Description
public	FieldStepNormalizer(final double fixed time step (sign is not used) h, final FieldFixedStepHandler<T> fixed time step handler to wrap handler) Simple constructor.
public	FieldStepNormalizer(final double fixed time step (sign is not used) h, final FieldFixedStepHandler<T> fixed time step handler to wrap handler, final StepNormalizerMode step normalizer mode to use mode) Simple constructor.
public	FieldStepNormalizer(final double fixed time step (sign is not used) h, final FieldFixedStepHandler<T> fixed time step handler to wrap handler, final StepNormalizerBounds step normalizer bounds setting to use bounds) Simple constructor.
public	FieldStepNormalizer(final double fixed time step (sign is not used) h, final FieldFixedStepHandler<T> fixed time step handler to wrap handler, final StepNormalizerMode step normalizer mode to use mode, final StepNormalizerBounds step normalizer bounds setting to use bounds) Simple constructor.

Modifier and Type	Method and Description
private void	doNormalizedStep(final boolean true if the step is the last one isLast) Invokes the underlying step handler for the current normalized step.
public void	handleStep(final FieldStepInterpolator<T> interpolator for the last accepted step. For efficiency purposes, the various integrators reuse the same object on each call, so if the instance wants to keep it across all calls (for example to provide at the end of the integration a continuous model valid throughout the integration range), it should build a local copy using the clone method and store this copy. interpolator, final boolean true if the step is the last one isLast) Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.handleStep. Handle the last accepted step
public void	init(final FieldODEStateAndDerivative<T> initial time, state vector and derivative initialState, final T target time for the integration finalTime) Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.init. Initialize step handler at the start of an ODE integration.
private boolean	Returns: value indicating whether the next normalized time is in the current step isNextInStep(final T the next normalized time nextTime, final FieldStepInterpolator<T> interpolator for the last accepted step, to use to get the end time of the current step interpolator) Returns a value indicating whether the next normalized time is in the current step.

bounds	back to summary
private final StepNormalizerBounds bounds The step normalizer bounds settings to use.

first	back to summary
private FieldODEStateAndDerivative<T> first First step state.

forward	back to summary
private boolean forward Integration direction indicator.

h	back to summary
private double h Fixed time step.

handler	back to summary
private final FieldFixedStepHandler<T> handler Underlying step handler.

last	back to summary
private FieldODEStateAndDerivative<T> last Last step step.

mode	back to summary
private final StepNormalizerMode mode The step normalizer mode to use.

Constructor Detail

FieldStepNormalizer back to summary

FieldStepNormalizer	back to summary
public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler) Simple constructor. Uses `INCREMENT` mode, and `FIRST` bounds setting, for backwards compatibility. Parameters h:double fixed time step (sign is not used) handler:FieldFixedStepHandler<T> fixed time step handler to wrap

public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler)

Simple constructor. Uses INCREMENT mode, and FIRST bounds setting, for backwards compatibility.

Parameters

h:double: fixed time step (sign is not used)
handler:FieldFixedStepHandler<T>: fixed time step handler to wrap

FieldStepNormalizer back to summary

FieldStepNormalizer	back to summary
public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerMode mode) Simple constructor. Uses `FIRST` bounds setting. Parameters h:double fixed time step (sign is not used) handler:FieldFixedStepHandler<T> fixed time step handler to wrap mode:StepNormalizerMode step normalizer mode to use Since 3.0

public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerMode mode)

Simple constructor. Uses FIRST bounds setting.

Parameters

h:double: fixed time step (sign is not used)
handler:FieldFixedStepHandler<T>: fixed time step handler to wrap
mode:StepNormalizerMode: step normalizer mode to use

Since

3.0

FieldStepNormalizer back to summary

FieldStepNormalizer	back to summary
public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerBounds bounds) Simple constructor. Uses `INCREMENT` mode. Parameters h:double fixed time step (sign is not used) handler:FieldFixedStepHandler<T> fixed time step handler to wrap bounds:StepNormalizerBounds step normalizer bounds setting to use Since 3.0

public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerBounds bounds)

Simple constructor. Uses INCREMENT mode.

Parameters

h:double: fixed time step (sign is not used)
handler:FieldFixedStepHandler<T>: fixed time step handler to wrap
bounds:StepNormalizerBounds: step normalizer bounds setting to use

Since

3.0

FieldStepNormalizer	back to summary
public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerMode mode, final StepNormalizerBounds bounds) Simple constructor. Parameters h:double fixed time step (sign is not used) handler:FieldFixedStepHandler<T> fixed time step handler to wrap mode:StepNormalizerMode step normalizer mode to use bounds:StepNormalizerBounds step normalizer bounds setting to use Since 3.0

FieldStepNormalizer

back to summary

public FieldStepNormalizer(final double h, final FieldFixedStepHandler<T> handler, final StepNormalizerMode mode, final StepNormalizerBounds bounds)

Simple constructor.

Parameters

h:double: fixed time step (sign is not used)
handler:FieldFixedStepHandler<T>: fixed time step handler to wrap
mode:StepNormalizerMode: step normalizer mode to use
bounds:StepNormalizerBounds: step normalizer bounds setting to use

Since

3.0

Method Detail

doNormalizedStep	back to summary
private void doNormalizedStep(final boolean isLast) Invokes the underlying step handler for the current normalized step. Parameters isLast:boolean true if the step is the last one

doNormalizedStep

back to summary

private void doNormalizedStep(final boolean isLast)

Invokes the underlying step handler for the current normalized step.

Parameters

isLast:boolean: true if the step is the last one

handleStep	back to summary
public void handleStep(final FieldStepInterpolator<T> interpolator, final boolean isLast) throws MaxCountExceededException Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.handleStep. Handle the last accepted step Parameters interpolator:FieldStepInterpolator<T> interpolator for the last accepted step. For efficiency purposes, the various integrators reuse the same object on each call, so if the instance wants to keep it across all calls (for example to provide at the end of the integration a continuous model valid throughout the integration range), it should build a local copy using the clone method and store this copy. isLast:boolean true if the step is the last one Exceptions MaxCountExceededException: if the interpolator throws one because the number of functions evaluations is exceeded

handleStep

back to summary

public void handleStep(final FieldStepInterpolator<T> interpolator, final boolean isLast) throws MaxCountExceededException

Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.handleStep.

Handle the last accepted step

Parameters

interpolator:FieldStepInterpolator<T>: interpolator for the last accepted step. For efficiency purposes, the various integrators reuse the same object on each call, so if the instance wants to keep it across all calls (for example to provide at the end of the integration a continuous model valid throughout the integration range), it should build a local copy using the clone method and store this copy.
isLast:boolean: true if the step is the last one

Exceptions

MaxCountExceededException:: if the interpolator throws one because the number of functions evaluations is exceeded

init	back to summary
public void init(final FieldODEStateAndDerivative<T> initialState, final T finalTime) Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.init. Doc from org.apache.commons.math3.ode.sampling.FieldStepHandler.init. Initialize step handler at the start of an ODE integration. This method is called once at the start of the integration. It may be used by the step handler to initialize some internal data if needed. Parameters initialState:FieldODEStateAndDerivative<T> initial time, state vector and derivative finalTime:T target time for the integration

init

back to summary

public void init(final FieldODEStateAndDerivative<T> initialState, final T finalTime)

Implements org.apache.commons.math3.ode.sampling.FieldStepHandler.init.

Doc from org.apache.commons.math3.ode.sampling.FieldStepHandler.init.

Initialize step handler at the start of an ODE integration.

This method is called once at the start of the integration. It may be used by the step handler to initialize some internal data if needed.

Parameters

initialState:FieldODEStateAndDerivative<T>: initial time, state vector and derivative
finalTime:T: target time for the integration

isNextInStep	back to summary
private boolean isNextInStep(final T nextTime, final FieldStepInterpolator<T> interpolator) Returns a value indicating whether the next normalized time is in the current step. Parameters nextTime:T the next normalized time interpolator:FieldStepInterpolator<T> interpolator for the last accepted step, to use to get the end time of the current step Returns:boolean value indicating whether the next normalized time is in the current step

isNextInStep

back to summary

private boolean isNextInStep(final T nextTime, final FieldStepInterpolator<T> interpolator)

Returns a value indicating whether the next normalized time is in the current step.

Parameters

nextTime:T: the next normalized time
interpolator:FieldStepInterpolator<T>: interpolator for the last accepted step, to use to get the end time of the current step

Returns:boolean

value indicating whether the next normalized time is in the current step

public Class FieldStepNormalizer<T extends RealFieldElement<T>>

Field Summary

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Field Detail

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