Package org.apache.commons.math3.ode.sampling

Class StepNormalizer

java.lang.Object
org.apache.commons.math3.ode.sampling.StepNormalizer
All Implemented Interfaces:
StepHandler
public class StepNormalizer extends Object implements StepHandler
This class wraps an object implementing FixedStepHandler into a StepHandler.

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 FixedStepHandler 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 timeEnd time DirectionMode BoundsOutput
0.33.1forwardINCREMENTNEITHER0.8, 1.3, 1.8, 2.3, 2.8
0.33.1forwardINCREMENTFIRST0.3, 0.8, 1.3, 1.8, 2.3, 2.8
0.33.1forwardINCREMENTLAST0.8, 1.3, 1.8, 2.3, 2.8, 3.1
0.33.1forwardINCREMENTBOTH0.3, 0.8, 1.3, 1.8, 2.3, 2.8, 3.1
0.33.1forwardMULTIPLESNEITHER0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.33.1forwardMULTIPLESFIRST0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.33.1forwardMULTIPLESLAST0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1
0.33.1forwardMULTIPLESBOTH0.3, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.1
0.03.0forwardINCREMENTNEITHER0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardINCREMENTFIRST0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardINCREMENTLAST0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardINCREMENTBOTH0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardMULTIPLESNEITHER0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardMULTIPLESFIRST0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardMULTIPLESLAST0.5, 1.0, 1.5, 2.0, 2.5, 3.0
0.03.0forwardMULTIPLESBOTH0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0
3.10.3backwardINCREMENTNEITHER2.6, 2.1, 1.6, 1.1, 0.6
3.10.3backwardINCREMENTFIRST3.1, 2.6, 2.1, 1.6, 1.1, 0.6
3.10.3backwardINCREMENTLAST2.6, 2.1, 1.6, 1.1, 0.6, 0.3
3.10.3backwardINCREMENTBOTH3.1, 2.6, 2.1, 1.6, 1.1, 0.6, 0.3
3.10.3backwardMULTIPLESNEITHER3.0, 2.5, 2.0, 1.5, 1.0, 0.5
3.10.3backwardMULTIPLESFIRST3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5
3.10.3backwardMULTIPLESLAST3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3
3.10.3backwardMULTIPLESBOTH3.1, 3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.3
3.00.0backwardINCREMENTNEITHER2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardINCREMENTFIRST3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardINCREMENTLAST2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardINCREMENTBOTH3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardMULTIPLESNEITHER2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardMULTIPLESFIRST3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardMULTIPLESLAST2.5, 2.0, 1.5, 1.0, 0.5, 0.0
3.00.0backwardMULTIPLESBOTH3.0, 2.5, 2.0, 1.5, 1.0, 0.5, 0.0

Since:
1.2
See Also:

  • Constructor Details

    • StepNormalizer

      public StepNormalizer(double h, FixedStepHandler handler)
      Simple constructor. Uses INCREMENT mode, and FIRST bounds setting, for backwards compatibility.
      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. Uses FIRST bounds setting.
      Parameters:
      h - fixed time step (sign is not used)
      handler - fixed time step handler to wrap
      mode - step normalizer mode to use
      Since:
      3.0

    • StepNormalizer

      public StepNormalizer(double h, FixedStepHandler handler, StepNormalizerBounds bounds)
      Simple constructor. Uses INCREMENT mode.
      Parameters:
      h - fixed time step (sign is not used)
      handler - fixed time step handler to wrap
      bounds - 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 wrap
      mode - step normalizer mode to use
      bounds - step normalizer bounds setting to use
      Since:
      3.0

  • Method Details

    • 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 interface StepHandler
      Parameters:
      t0 - start value of the independent time variable
      y0 - array containing the start value of the state vector
      t - target time for the integration

    • handleStep

      public void handleStep(StepInterpolator interpolator, boolean isLast) throws MaxCountExceededException
      Handle the last accepted step
      Specified by:
      handleStep in interface StepHandler
      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