Package nl.tudelft.simulation.jstats.ode

Class DifferentialEquation

java.lang.Object

org.djutils.event.LocalEventProducer

nl.tudelft.simulation.jstats.ode.DifferentialEquation

All Implemented Interfaces:

Serializable, Remote, DifferentialEquationInterface, EventProducer

Direct Known Subclasses:

DifferentialEquation

public abstract class DifferentialEquation
extends LocalEventProducer
implements DifferentialEquationInterface

The DifferentialEquation is the abstract basis for the DESS formalism.

Copyright (c) 2002-2023 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See for project information https://simulation.tudelft.nl. The DSOL project is distributed under a three-clause BSD-style license, which can be found at https://https://simulation.tudelft.nl/dsol/docs/latest/license.html.

Author:

Alexander Verbraeck, Peter Jacobs

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected double	lastX	the last x value, initialized with x0 to start integration.
protected double[]	lastY	the last calculated value array for lastX, initialized with the initial value array y0.
protected double	stepSize	the stepSize; can be negative or positive.

Fields inherited from interface org.djutils.event.EventProducer

FIRST_POSITION, LAST_POSITION

Constructor Summary

Constructors

Constructor	Description
DifferentialEquation(double stepSize, NumericalIntegratorType integratorType)	constructs a new DifferentialEquation with a user-specified integrator.

Method Summary

Modifier and Type	Method	Description
NumericalIntegrator	getIntegrator()
void	initialize(double x0, double[] y0)	initializes the differential equation.
protected double[]	integrateY(double x, double initialX, double[] initialY)	integrates Y.
void	setIntegrator(NumericalIntegrator integrator)
double[]	y(double x)	returns y as a function of x.

Methods inherited from class org.djutils.event.LocalEventProducer

addListener, addListener, addListener, addListener, fireEvent, fireEvent, fireEvent, fireTimedEvent, fireTimedEvent, fireTimedEvent, fireUnverifiedEvent, fireUnverifiedEvent, fireUnverifiedTimedEvent, fireUnverifiedTimedEvent, getEventListenerMap, getEventTypesWithListeners, getListenerReferences, hasListeners, numberOfListeners, removeAllListeners, removeAllListeners, removeListener

Methods inherited from class java.lang.Object

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

Methods inherited from interface nl.tudelft.simulation.jstats.ode.DifferentialEquationInterface

dy

Field Detail

lastY

protected double[] lastY

the last calculated value array for lastX, initialized with the initial value array y0.

stepSize

protected double stepSize

the stepSize; can be negative or positive.

lastX

protected double lastX

the last x value, initialized with x0 to start integration.

Constructor Detail

DifferentialEquation

public DifferentialEquation(double stepSize,
                            NumericalIntegratorType integratorType)

constructs a new DifferentialEquation with a user-specified integrator.

Parameters:

stepSize - double; the stepSize to use.

integratorType - NumericalIntegratorType; the integrator to use.

Method Detail

initialize

public void initialize(double x0,
                       double[] y0)

initializes the differential equation.

Specified by:

initialize in interface DifferentialEquationInterface

Parameters:

x0 - double; the initial x-value

y0 - double[]; the initial y-value array

y

public double[] y(double x)

returns y as a function of x.

Specified by:

y in interface DifferentialEquationInterface

Parameters:

x - double; the x-value

Returns:

y

integrateY

protected double[] integrateY(double x,
                              double initialX,
                              double[] initialY)

integrates Y.

Parameters:

x - double; the x-value

initialX - double; the initial X value, non-final (will be updated)

initialY - double[]; the initial Y value, non-final (will be updated)

Returns:

the new Y value

getIntegrator

public NumericalIntegrator getIntegrator()

Returns:

Returns the integrator.

setIntegrator

public void setIntegrator(NumericalIntegrator integrator)

Parameters:

integrator - NumericalIntegrator; The integrator to set.