org.hipparchus.ode.nonstiff

Class StepsizeHelper

java.lang.Object

org.hipparchus.ode.nonstiff.StepsizeHelper

public class StepsizeHelper
extends Object

Helper for adaptive stepsize control.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
StepsizeHelper(double minStep, double maxStep, double[] vecAbsoluteTolerance, double[] vecRelativeTolerance) Simple constructor..
StepsizeHelper(double minStep, double maxStep, double scalAbsoluteTolerance, double scalRelativeTolerance) Simple constructor.

Method Summary

Modifier and Type	Method and Description
double	filterStep(double h, boolean forward, boolean acceptSmall) Filter the integration step.
<T extends CalculusFieldElement<T>> T	filterStep(T h, boolean forward, boolean acceptSmall) Filter the integration step.
double	getDummyStepsize() Get a dummy step size.
double	getInitialStep() Get the initial step.
int	getMainSetDimension() Get the main set dimension.
double	getMaxStep() Get the maximal step.
double	getMinStep() Get the minimal step.
double	getRelativeTolerance(int i) Get the relative tolerance for one component.
double	getTolerance(int i, double scale) Get the tolerance for one component.
<T extends CalculusFieldElement<T>> T	getTolerance(int i, T scale) Get the tolerance for one component.
void	setInitialStepSize(double initialStepSize) Set the initial step size.
protected void	setMainSetDimension(int mainSetDimension) Set main set dimension.

Methods inherited from class java.lang.Object

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

Constructor Detail

StepsizeHelper

public StepsizeHelper(double minStep,
                      double maxStep,
                      double scalAbsoluteTolerance,
                      double scalRelativeTolerance)

Simple constructor.

Parameters:

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

StepsizeHelper

public StepsizeHelper(double minStep,
                      double maxStep,
                      double[] vecAbsoluteTolerance,
                      double[] vecRelativeTolerance)

Simple constructor..

Parameters:

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

Method Detail

setMainSetDimension

protected void setMainSetDimension(int mainSetDimension)
                            throws MathIllegalArgumentException

Set main set dimension.

Parameters:

mainSetDimension - dimension of the main set

Throws:

MathIllegalArgumentException - if adaptive step size integrators tolerance arrays dimensions are not compatible with equations settings

getMainSetDimension

public int getMainSetDimension()

Get the main set dimension.

Returns:

main set dimension

getRelativeTolerance

public double getRelativeTolerance(int i)

Get the relative tolerance for one component.

Parameters:

i - component to select

Returns:

relative tolerance for selected component

getTolerance

public double getTolerance(int i,
                           double scale)

Get the tolerance for one component.

Parameters:

i - component to select

scale - scale factor for relative tolerance (i.e. y[i])

Returns:

tolerance for selected component

getTolerance

public <T extends CalculusFieldElement<T>> T getTolerance(int i,
                                                          T scale)

Get the tolerance for one component.

Type Parameters:

T - type of the field elements

Parameters:

i - component to select

scale - scale factor for relative tolerance (i.e. y[i])

Returns:

tolerance for selected component

filterStep

public double filterStep(double h,
                         boolean forward,
                         boolean acceptSmall)
                  throws MathIllegalArgumentException

Filter the integration step.

Parameters:

h - signed step

forward - forward integration indicator

acceptSmall - if true, steps smaller than the minimal value are silently increased up to this value, if false such small steps generate an exception

Returns:

a bounded integration step (h if no bound is reach, or a bounded value)

Throws:

MathIllegalArgumentException - if the step is too small and acceptSmall is false

filterStep

public <T extends CalculusFieldElement<T>> T filterStep(T h,
                                                        boolean forward,
                                                        boolean acceptSmall)
                                                 throws MathIllegalArgumentException

Filter the integration step.

Type Parameters:

T - type of the field elements

Parameters:

h - signed step

forward - forward integration indicator

acceptSmall - if true, steps smaller than the minimal value are silently increased up to this value, if false such small steps generate an exception

Returns:

a bounded integration step (h if no bound is reach, or a bounded value)

Throws:

MathIllegalArgumentException - if the step is too small and acceptSmall is false

setInitialStepSize

public void setInitialStepSize(double initialStepSize)

Set the initial step size.

This method allows the user to specify an initial positive step size instead of letting the integrator guess it by itself. If this method is not called before integration is started, the initial step size will be estimated by the integrator.

Parameters:

initialStepSize - initial step size to use (must be positive even for backward integration ; providing a negative value or a value outside of the min/max step interval will lead the integrator to ignore the value and compute the initial step size by itself)

getInitialStep

public double getInitialStep()

Get the initial step.

Returns:

initial step

getMinStep

public double getMinStep()

Get the minimal step.

Returns:

minimal step

getMaxStep

public double getMaxStep()

Get the maximal step.

Returns:

maximal step

getDummyStepsize

public double getDummyStepsize()

Get a dummy step size.

Returns:

geometric mean of getMinStep() and getMaxStep()