org.apache.commons.math.ode

Interface FirstOrderDifferentialEquations

All Known Subinterfaces:

ExtendedFirstOrderDifferentialEquations, ODEWithJacobians, ParameterizedODE

All Known Implementing Classes:

FirstOrderConverter

public interface FirstOrderDifferentialEquations

This interface represents a first order differential equations set.

This interface should be implemented by all real first order differential equation problems before they can be handled by the integrators FirstOrderIntegrator.integrate(org.apache.commons.math.ode.FirstOrderDifferentialEquations, double, double[], double, double[]) method.

A first order differential equations problem, as seen by an integrator is the time derivative dY/dt of a state vector Y, both being one dimensional arrays. From the integrator point of view, this derivative depends only on the current time t and on the state vector Y.

For real problems, the derivative depends also on parameters that do not belong to the state vector (dynamical model constants for example). These constants are completely outside of the scope of this interface, the classes that implement it are allowed to handle them as they want.

Since:

1.2

See Also:

FirstOrderIntegrator, FirstOrderConverter, SecondOrderDifferentialEquations

Method Summary

Modifier and Type	Method and Description
void	computeDerivatives(double t, double[] y, double[] yDot) Get the current time derivative of the state vector.
int	getDimension() Get the dimension of the problem.

Method Detail

getDimension

int getDimension()

Get the dimension of the problem.

Returns:

dimension of the problem

computeDerivatives

void computeDerivatives(double t,
                        double[] y,
                        double[] yDot)
                 throws DerivativeException

Get the current time derivative of the state vector.

Parameters:

t - current value of the independent time variable

y - array containing the current value of the state vector

yDot - placeholder array where to put the time derivative of the state vector

Throws:

DerivativeException - this user-defined exception should be used if an error is is triggered by user code