Class StepNormalizer
- java.lang.Object
-
- org.apache.commons.math3.ode.sampling.StepNormalizer
-
- All Implemented Interfaces:
StepHandler
public class StepNormalizer extends java.lang.Object implements StepHandler
This class wraps an object implementingFixedStepHandler
into aStepHandler
.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 underlyingFixedStepHandler
object is called at normalized times. The normalized times can be influenced by theStepNormalizerMode
andStepNormalizerBounds
.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 - Since:
- 1.2
- See Also:
StepHandler
,FixedStepHandler
,StepNormalizerMode
,StepNormalizerBounds
-
-
Field Summary
Fields Modifier and Type Field Description private StepNormalizerBounds
bounds
The step normalizer bounds settings to use.private double
firstTime
First step time.private boolean
forward
Integration direction indicator.private double
h
Fixed time step.private FixedStepHandler
handler
Underlying step handler.private double[]
lastDerivatives
Last derivatives vector.private double[]
lastState
Last state vector.private double
lastTime
Last step time.private StepNormalizerMode
mode
The step normalizer mode to use.
-
Constructor Summary
Constructors Constructor Description StepNormalizer(double h, FixedStepHandler handler)
Simple constructor.StepNormalizer(double h, FixedStepHandler handler, StepNormalizerBounds bounds)
Simple constructor.StepNormalizer(double h, FixedStepHandler handler, StepNormalizerMode mode)
Simple constructor.StepNormalizer(double h, FixedStepHandler handler, StepNormalizerMode mode, StepNormalizerBounds bounds)
Simple constructor.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private void
doNormalizedStep(boolean isLast)
Invokes the underlying step handler for the current normalized step.void
handleStep(StepInterpolator interpolator, boolean isLast)
Handle the last accepted stepvoid
init(double t0, double[] y0, double t)
Initialize step handler at the start of an ODE integration.private boolean
isNextInStep(double nextTime, StepInterpolator interpolator)
Returns a value indicating whether the next normalized time is in the current step.private void
storeStep(StepInterpolator interpolator, double t)
Stores the interpolated information for the given time in the current state.
-
-
-
Field Detail
-
h
private double h
Fixed time step.
-
handler
private final FixedStepHandler handler
Underlying step handler.
-
firstTime
private double firstTime
First step time.
-
lastTime
private double lastTime
Last step time.
-
lastState
private double[] lastState
Last state vector.
-
lastDerivatives
private double[] lastDerivatives
Last derivatives vector.
-
forward
private boolean forward
Integration direction indicator.
-
bounds
private final StepNormalizerBounds bounds
The step normalizer bounds settings to use.
-
mode
private final StepNormalizerMode mode
The step normalizer mode to use.
-
-
Constructor Detail
-
StepNormalizer
public StepNormalizer(double h, FixedStepHandler handler)
- Parameters:
h
- fixed time step (sign is not used)handler
- fixed time step handler to wrap
-
StepNormalizer
public StepNormalizer(double h, FixedStepHandler handler, StepNormalizerMode mode)
Simple constructor. UsesFIRST
bounds setting.- Parameters:
h
- fixed time step (sign is not used)handler
- fixed time step handler to wrapmode
- step normalizer mode to use- Since:
- 3.0
-
StepNormalizer
public StepNormalizer(double h, FixedStepHandler handler, StepNormalizerBounds bounds)
Simple constructor. UsesINCREMENT
mode.- Parameters:
h
- fixed time step (sign is not used)handler
- fixed time step handler to wrapbounds
- step normalizer bounds setting to use- Since:
- 3.0
-
StepNormalizer
public StepNormalizer(double h, FixedStepHandler handler, StepNormalizerMode mode, StepNormalizerBounds bounds)
Simple constructor.- Parameters:
h
- fixed time step (sign is not used)handler
- fixed time step handler to wrapmode
- step normalizer mode to usebounds
- step normalizer bounds setting to use- Since:
- 3.0
-
-
Method Detail
-
init
public void init(double t0, double[] y0, double t)
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.
- Specified by:
init
in interfaceStepHandler
- Parameters:
t0
- start value of the independent time variabley0
- array containing the start value of the state vectort
- target time for the integration
-
handleStep
public void handleStep(StepInterpolator interpolator, boolean isLast) throws MaxCountExceededException
Handle the last accepted step- Specified by:
handleStep
in interfaceStepHandler
- Parameters:
interpolator
- 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
- true if the step is the last one- Throws:
MaxCountExceededException
- if the interpolator throws one because the number of functions evaluations is exceeded
-
isNextInStep
private boolean isNextInStep(double nextTime, StepInterpolator interpolator)
Returns a value indicating whether the next normalized time is in the current step.- Parameters:
nextTime
- the next normalized timeinterpolator
- interpolator for the last accepted step, to use to get the end time of the current step- Returns:
- value indicating whether the next normalized time is in the current step
-
doNormalizedStep
private void doNormalizedStep(boolean isLast)
Invokes the underlying step handler for the current normalized step.- Parameters:
isLast
- true if the step is the last one
-
storeStep
private void storeStep(StepInterpolator interpolator, double t) throws MaxCountExceededException
Stores the interpolated information for the given time in the current state.- Parameters:
interpolator
- interpolator for the last accepted step, to use to get the interpolated informationt
- the time for which to store the interpolated information- Throws:
MaxCountExceededException
- if the interpolator throws one because the number of functions evaluations is exceeded
-
-