org.apache.commons.math.ode
Class TestProblem4

java.lang.Object
  extended by org.apache.commons.math.ode.TestProblemAbstract
      extended by 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


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