org.apache.commons.math.ode
Class TestProblem4

java.lang.Object
  org.apache.commons.math.ode.TestProblemAbstract
      org.apache.commons.math.ode.TestProblem4

All Implemented Interfaces:

org.apache.commons.math.ode.FirstOrderDifferentialEquations

public class TestProblem4
extends TestProblemAbstract

This class is used in the junit tests for the ODE integrators.

This specific problem is the following differential equation :

    x'' = -x
 

And when x decreases down to 0, the state should be changed as follows :

   x' -> -x'
 

The theoretical solution of this problem is x = |sin(t+a)|

Field Summary

Fields inherited from class org.apache.commons.math.ode.TestProblemAbstract

calls, errorScale, n, t0, t1, y0

Constructor Summary

TestProblem4()
Simple constructor.

TestProblem4(TestProblem4 problem)
Copy constructor.

Method Summary

double[]	computeTheoreticalState(double t) Compute the theoretical state at the specified time.
TestProblem4	copy() Copy operation.
void	doComputeDerivatives(double t, double[] y, double[] yDot)
org.apache.commons.math.ode.events.EventHandler[]	getEventsHandlers() Get the events handlers.

Methods inherited from class org.apache.commons.math.ode.TestProblemAbstract

computeDerivatives, getCalls, getDimension, getErrorScale, getFinalTime, getInitialState, getInitialTime, setErrorScale, setFinalConditions, setInitialConditions

Methods inherited from class java.lang.Object

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

Constructor Detail

TestProblem4

public TestProblem4()

Simple constructor.

TestProblem4

public TestProblem4(TestProblem4 problem)

Copy constructor.

Parameters:

problem - problem to copy

Method Detail

copy

public TestProblem4 copy()

Copy operation.

Specified by:

copy in class TestProblemAbstract

Returns:

a copy of the instance

getEventsHandlers

public org.apache.commons.math.ode.events.EventHandler[] getEventsHandlers()

Description copied from class: TestProblemAbstract

Get the events handlers.

Overrides:

getEventsHandlers in class TestProblemAbstract

Returns:

events handlers

doComputeDerivatives

public void doComputeDerivatives(double t,
                                 double[] y,
                                 double[] yDot)

Specified by:

doComputeDerivatives in class TestProblemAbstract

computeTheoreticalState

public double[] computeTheoreticalState(double t)

Description copied from class: TestProblemAbstract

Compute the theoretical state at the specified time.

Specified by:

computeTheoreticalState in class TestProblemAbstract

Parameters:

t - time at which the state is required

Returns:

state vector at time t