Package org.hipparchus.ode
Class ExpandableODE
java.lang.Object
org.hipparchus.ode.ExpandableODE
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.

Constructor Summary
ConstructorDescriptionBuild an expandable set from its primary ODE set. 
Method Summary
Modifier and TypeMethodDescriptionint
addSecondaryEquations
(SecondaryODE secondary) Add a set of secondary equations to be integrated along with the primary set.double[]
computeDerivatives
(double t, double[] y) Get the current time derivative of the complete state vector.Get the mapper for the set of equations.Get the primary set of differential equations to be integrated.void
Initialize equations at the start of an ODE integration.

Constructor Details

ExpandableODE
Build an expandable set from its primary ODE set. Parameters:
primary
 the primary set of differential equations to be integrated.


Method Details

getPrimary
Get the primary set of differential equations to be integrated. Returns:
 primary set of differential equations to be integrated

getMapper
Get the mapper for the set of equations. Returns:
 mapper for the set of equations

addSecondaryEquations
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, to be used
as the parameter to
FieldODEState.getSecondaryState(int)
andFieldODEStateAndDerivative.getSecondaryDerivative(int)
(beware index 0 corresponds to primary state, secondary states start at 1)

init
Initialize equations at the start of an ODE integration. Parameters:
s0
 state at integration startfinalTime
 target time for the integration Throws:
MathIllegalStateException
 if the number of functions evaluations is exceededMathIllegalArgumentException
 if arrays dimensions do not match equations settings

computeDerivatives
public double[] computeDerivatives(double t, double[] y) throws MathIllegalArgumentException, MathIllegalStateException Get the current time derivative of the complete state vector. Parameters:
t
 current value of the independent time variabley
 array containing the current value of the complete state vector Returns:
 time derivative of the complete state vector
 Throws:
MathIllegalStateException
 if the number of functions evaluations is exceededMathIllegalArgumentException
 if arrays dimensions do not match equations settings
