org.jscience.mathematics.analysis.ode
Interface StepInterpolator

All Superinterfaces:
java.io.Externalizable, java.io.Serializable
All Known Implementing Classes:
AbstractStepInterpolator, DummyStepInterpolator

public interface StepInterpolator
extends java.io.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).

See Also:
FirstOrderIntegrator, SecondOrderIntegrator, StepHandler

Method Summary
 double getCurrentTime()
          Get the current grid point time.
 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. If setInterpolatedTime(double) has not been called, it returns the current grid point time.

Returns:
interpolation point time

setInterpolatedTime

void setInterpolatedTime(double time)
                         throws DerivativeException
Set the time of the interpolated point.

Setting the time outside of the current step is now allowed (it was not allowed up to version 5.4 of Mantissa), 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.

Parameters:
time - time of the interpolated point
Throws:
DerivativeException - if this call induces an automatic step finalization that throws one

getInterpolatedState

double[] getInterpolatedState()
Get the state vector of the interpolated point.

Returns:
state vector at time getInterpolatedTime()

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 switching function triggering.

Returns:
true if the integration variable (time) increases during integration