org.apache.commons.math3.ode
Class ExpandableStatefulODE

java.lang.Object
  extended by org.apache.commons.math3.ode.ExpandableStatefulODE

public class ExpandableStatefulODE
extends Object

This class represents a combined set of first order differential equations, with at least a primary set of equations expandable by some sets of secondary equations.

One typical use case is the computation of the Jacobian matrix for some ODE. In this case, the primary set of equations corresponds to the raw ODE, and we add to this set another bunch of secondary equations which represent the Jacobian matrix of the primary set.

We want the integrator to use only the primary set to estimate the errors and hence the step sizes. It should not use the secondary equations in this computation. The integrator will be able to know where the primary set ends and so where the secondary sets begin.

Since:
3.0
Version:
$Id: ExpandableStatefulODE.java 1416643 2012-12-03 19:37:14Z tn $
See Also:
FirstOrderDifferentialEquations, JacobianMatrices

Constructor Summary
ExpandableStatefulODE(FirstOrderDifferentialEquations primary)
          Build an expandable set from its primary ODE set.
 
Method Summary
 int addSecondaryEquations(SecondaryEquations secondary)
          Add a set of secondary equations to be integrated along with the primary set.
 void computeDerivatives(double t, double[] y, double[] yDot)
          Get the current time derivative of the complete state vector.
 double[] getCompleteState()
          Get the complete current state.
 FirstOrderDifferentialEquations getPrimary()
          Get the primary set of differential equations.
 EquationsMapper getPrimaryMapper()
          Get an equations mapper for the primary equations set.
 double[] getPrimaryState()
          Get primary part of the current state.
 double[] getPrimaryStateDot()
          Get primary part of the current state derivative.
 EquationsMapper[] getSecondaryMappers()
          Get the equations mappers for the secondary equations sets.
 double[] getSecondaryState(int index)
          Get secondary part of the current state.
 double[] getSecondaryStateDot(int index)
          Get secondary part of the current state derivative.
 double getTime()
          Get current time.
 int getTotalDimension()
          Return the dimension of the complete set of equations.
 void setCompleteState(double[] completeState)
          Set the complete current state.
 void setPrimaryState(double[] primaryState)
          Set primary part of the current state.
 void setSecondaryState(int index, double[] secondaryState)
          Set secondary part of the current state.
 void setTime(double time)
          Set current time.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ExpandableStatefulODE

public ExpandableStatefulODE(FirstOrderDifferentialEquations primary)
Build an expandable set from its primary ODE set.

Parameters:
primary - the primary set of differential equations to be integrated.
Method Detail

getPrimary

public FirstOrderDifferentialEquations getPrimary()
Get the primary set of differential equations.

Returns:
primary set of differential equations

getTotalDimension

public int getTotalDimension()
Return the dimension of the complete set of equations.

The complete set of equations correspond to the primary set plus all secondary sets.

Returns:
dimension of the complete set of equations

computeDerivatives

public void computeDerivatives(double t,
                               double[] y,
                               double[] yDot)
                        throws MaxCountExceededException,
                               DimensionMismatchException
Get the current time derivative of the complete state vector.

Parameters:
t - current value of the independent time variable
y - array containing the current value of the complete state vector
yDot - placeholder array where to put the time derivative of the complete state vector
Throws:
MaxCountExceededException - if the number of functions evaluations is exceeded
DimensionMismatchException - if arrays dimensions do not match equations settings

addSecondaryEquations

public int addSecondaryEquations(SecondaryEquations secondary)
Add a set of secondary equations to be integrated along with the primary set.

Parameters:
secondary - secondary equations set
Returns:
index of the secondary equation in the expanded state

getPrimaryMapper

public EquationsMapper getPrimaryMapper()
Get an equations mapper for the primary equations set.

Returns:
mapper for the primary set
See Also:
getSecondaryMappers()

getSecondaryMappers

public EquationsMapper[] getSecondaryMappers()
Get the equations mappers for the secondary equations sets.

Returns:
equations mappers for the secondary equations sets
See Also:
getPrimaryMapper()

setTime

public void setTime(double time)
Set current time.

Parameters:
time - current time

getTime

public double getTime()
Get current time.

Returns:
current time

setPrimaryState

public void setPrimaryState(double[] primaryState)
                     throws DimensionMismatchException
Set primary part of the current state.

Parameters:
primaryState - primary part of the current state
Throws:
DimensionMismatchException - if the dimension of the array does not match the primary set

getPrimaryState

public double[] getPrimaryState()
Get primary part of the current state.

Returns:
primary part of the current state

getPrimaryStateDot

public double[] getPrimaryStateDot()
Get primary part of the current state derivative.

Returns:
primary part of the current state derivative

setSecondaryState

public void setSecondaryState(int index,
                              double[] secondaryState)
                       throws DimensionMismatchException
Set secondary part of the current state.

Parameters:
index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
secondaryState - secondary part of the current state
Throws:
DimensionMismatchException - if the dimension of the partial state does not match the selected equations set dimension

getSecondaryState

public double[] getSecondaryState(int index)
Get secondary part of the current state.

Parameters:
index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
Returns:
secondary part of the current state

getSecondaryStateDot

public double[] getSecondaryStateDot(int index)
Get secondary part of the current state derivative.

Parameters:
index - index of the part to set as returned by addSecondaryEquations(SecondaryEquations)
Returns:
secondary part of the current state derivative

setCompleteState

public void setCompleteState(double[] completeState)
                      throws DimensionMismatchException
Set the complete current state.

Parameters:
completeState - complete current state to copy data from
Throws:
DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension

getCompleteState

public double[] getCompleteState()
                          throws DimensionMismatchException
Get the complete current state.

Returns:
complete current state
Throws:
DimensionMismatchException - if the dimension of the complete state does not match the complete equations sets dimension


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