Interface StepInterpolator

 All Superinterfaces:
Externalizable
,Serializable
 All Known Implementing Classes:
AbstractStepInterpolator
,NordsieckStepInterpolator
public interface StepInterpolator extends Externalizable
This interface represents an interpolator over the last step during an ODE integration.The various ODE integrators provide objects implementing this interface to the step handlers. These objects are often custom objects tightly bound to the integrator internal algorithms. The handlers can use these objects to retrieve the state vector at intermediate times between the previous and the current grid points (this feature is often called dense output).
One important thing to note is that the step handlers may be so tightly bound to the integrators that they often share some internal state arrays. This imply that one should never use a direct reference to a step interpolator outside of the step handler, either for future use or for use in another thread. If such a need arise, the step interpolator must be copied using the dedicated
copy()
method. Since:
 1.2
 See Also:
FirstOrderIntegrator
,SecondOrderIntegrator
,StepHandler


Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description StepInterpolator
copy()
Copy the instance.double
getCurrentTime()
Get the current grid point time.double[]
getInterpolatedDerivatives()
Get the derivatives of the state vector of the interpolated point.double[]
getInterpolatedSecondaryDerivatives(int index)
Get the interpolated secondary derivatives corresponding to the secondary equations.double[]
getInterpolatedSecondaryState(int index)
Get the interpolated secondary state corresponding to the secondary equations.double[]
getInterpolatedState()
Get the state vector of the interpolated point.double
getInterpolatedTime()
Get the time of the interpolated point.double
getPreviousTime()
Get the previous grid point time.boolean
isForward()
Check if the natural integration direction is forward.void
setInterpolatedTime(double time)
Set the time of the interpolated point.
Methods inherited from interface java.io.Externalizable
readExternal, writeExternal




Method Detail

getPreviousTime
double getPreviousTime()
Get the previous grid point time. Returns:
 previous grid point time

getCurrentTime
double getCurrentTime()
Get the current grid point time. Returns:
 current grid point time

getInterpolatedTime
double getInterpolatedTime()
Get the time of the interpolated point. IfsetInterpolatedTime(double)
has not been called, it returns the current grid point time. Returns:
 interpolation point time

setInterpolatedTime
void setInterpolatedTime(double time)
Set the time of the interpolated point.Setting the time outside of the current step is now allowed, but should be used with care since the accuracy of the interpolator will probably be very poor far from this step. This allowance has been added to simplify implementation of search algorithms near the step endpoints.
Setting the time changes the instance internal state. This includes the internal arrays returned in
getInterpolatedState()
,getInterpolatedDerivatives()
,getInterpolatedSecondaryState(int)
andgetInterpolatedSecondaryDerivatives(int)
. So if their content must be preserved across several calls, user must copy them. Parameters:
time
 time of the interpolated point See Also:
getInterpolatedState()
,getInterpolatedDerivatives()
,getInterpolatedSecondaryState(int)
,getInterpolatedSecondaryDerivatives(int)

getInterpolatedState
double[] getInterpolatedState() throws MaxCountExceededException
Get the state vector of the interpolated point.The returned vector is a reference to a reused array, so it should not be modified and it should be copied if it needs to be preserved across several calls to the associated
setInterpolatedTime(double)
method. Returns:
 state vector at time
getInterpolatedTime()
 Throws:
MaxCountExceededException
 if the number of functions evaluations is exceeded See Also:
getInterpolatedDerivatives()
,getInterpolatedSecondaryState(int)
,getInterpolatedSecondaryDerivatives(int)
,setInterpolatedTime(double)

getInterpolatedDerivatives
double[] getInterpolatedDerivatives() throws MaxCountExceededException
Get the derivatives of the state vector of the interpolated point.The returned vector is a reference to a reused array, so it should not be modified and it should be copied if it needs to be preserved across several calls to the associated
setInterpolatedTime(double)
method. Returns:
 derivatives of the state vector at time
getInterpolatedTime()
 Throws:
MaxCountExceededException
 if the number of functions evaluations is exceeded Since:
 2.0
 See Also:
getInterpolatedState()
,getInterpolatedSecondaryState(int)
,getInterpolatedSecondaryDerivatives(int)
,setInterpolatedTime(double)

getInterpolatedSecondaryState
double[] getInterpolatedSecondaryState(int index) throws MaxCountExceededException
Get the interpolated secondary state corresponding to the secondary equations.The returned vector is a reference to a reused array, so it should not be modified and it should be copied if it needs to be preserved across several calls to the associated
setInterpolatedTime(double)
method. Parameters:
index
 index of the secondary set, as returned byExpandableStatefulODE.addSecondaryEquations(SecondaryEquations)
 Returns:
 interpolated secondary state at the current interpolation date
 Throws:
MaxCountExceededException
 if the number of functions evaluations is exceeded Since:
 3.0
 See Also:
getInterpolatedState()
,getInterpolatedDerivatives()
,getInterpolatedSecondaryDerivatives(int)
,setInterpolatedTime(double)

getInterpolatedSecondaryDerivatives
double[] getInterpolatedSecondaryDerivatives(int index) throws MaxCountExceededException
Get the interpolated secondary derivatives corresponding to the secondary equations.The returned vector is a reference to a reused array, so it should not be modified and it should be copied if it needs to be preserved across several calls.
 Parameters:
index
 index of the secondary set, as returned byExpandableStatefulODE.addSecondaryEquations(SecondaryEquations)
 Returns:
 interpolated secondary derivatives at the current interpolation date
 Throws:
MaxCountExceededException
 if the number of functions evaluations is exceeded Since:
 3.0
 See Also:
getInterpolatedState()
,getInterpolatedDerivatives()
,getInterpolatedSecondaryState(int)
,setInterpolatedTime(double)

isForward
boolean isForward()
Check if the natural integration direction is forward.This method provides the integration direction as specified by the integrator itself, it avoid some nasty problems in degenerated cases like null steps due to cancellation at step initialization, step control or discrete events triggering.
 Returns:
 true if the integration variable (time) increases during integration

copy
StepInterpolator copy() throws MaxCountExceededException
Copy the instance.The copied instance is guaranteed to be independent from the original one. Both can be used with different settings for interpolated time without any side effect.
 Returns:
 a deep copy of the instance, which can be used independently.
 Throws:
MaxCountExceededException
 if the number of functions evaluations is exceeded during step finalization See Also:
setInterpolatedTime(double)

