org.hipparchus.ode

Interface SecondaryODE

All Known Subinterfaces:

SecondaryEquations

public interface SecondaryODE

This interface allows users to add secondary differential equations to a primary set of differential equations.

In some cases users may need to integrate some problem-specific equations along with a primary set of differential equations. One example is optimal control where adjoined parameters linked to the minimized hamiltonian must be integrated.

This interface allows users to add such equations to a primary set of first order differential equations thanks to the ExpandableODE.addSecondaryEquations(SecondaryODE) method.

See Also:

ExpandableODE

Method Summary

Modifier and Type	Method and Description
double[]	computeDerivatives(double t, double[] primary, double[] primaryDot, double[] secondary) Compute the derivatives related to the secondary state parameters.
int	getDimension() Get the dimension of the secondary state parameters.
default void	init(double t0, double[] primary0, double[] secondary0, double finalTime) Initialize equations at the start of an ODE integration.

Method Detail

getDimension

int getDimension()

Get the dimension of the secondary state parameters.

Returns:

dimension of the secondary state parameters

init

default void init(double t0,
                  double[] primary0,
                  double[] secondary0,
                  double finalTime)

Initialize equations at the start of an ODE integration.

This method is called once at the start of the integration. It may be used by the equations to initialize some internal data if needed.

The default implementation does nothing.

Parameters:

t0 - value of the independent time variable at integration start

primary0 - array containing the value of the primary state vector at integration start

secondary0 - array containing the value of the secondary state vector at integration start

finalTime - target time for the integration

computeDerivatives

double[] computeDerivatives(double t,
                            double[] primary,
                            double[] primaryDot,
                            double[] secondary)
                     throws MathIllegalArgumentException,
                            MathIllegalStateException

Compute the derivatives related to the secondary state parameters.

Parameters:

t - current value of the independent time variable

primary - array containing the current value of the primary state vector

primaryDot - array containing the derivative of the primary state vector

secondary - array containing the current value of the secondary state vector

Returns:

derivative of the secondary state vector

Throws:

MathIllegalStateException - if the number of functions evaluations is exceeded

MathIllegalArgumentException - if arrays dimensions do not match equations settings