Package edu.wpi.first.math.system

Class NumericalIntegration

java.lang.Object

edu.wpi.first.math.system.NumericalIntegration

public final class NumericalIntegration
extends Object

Numerical integration utilities.

Method Summary

Modifier and Type	Method	Description
static <States extends Num, Inputs extends Num> Matrix<States,N1>	rk4(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds)	Performs 4th order Runge-Kutta integration of dx/dt = f(x, u) for dt.
static double	rk4(BiFunction<Double,Double,Double> f, double x, Double u, double dtSeconds)	Performs Runge Kutta integration (4th order).
static double	rk4(DoubleFunction<Double> f, double x, double dtSeconds)	Performs Runge Kutta integration (4th order).
static <States extends Num> Matrix<States,N1>	rk4(Function<Matrix<States,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, double dtSeconds)	Performs 4th order Runge-Kutta integration of dx/dt = f(x) for dt.
static <States extends Num, Inputs extends Num> Matrix<States,N1>	rkdp(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds)	Performs adaptive Dormand-Prince integration of dx/dt = f(x, u) for dt.
static <States extends Num, Inputs extends Num> Matrix<States,N1>	rkdp(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds, double maxError)	Performs adaptive Dormand-Prince integration of dx/dt = f(x, u) for dt.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

rk4

public static double rk4(DoubleFunction<Double> f, double x, double dtSeconds)

Performs Runge Kutta integration (4th order).

Parameters:

f - The function to integrate, which takes one argument x.

x - The initial value of x.

dtSeconds - The time over which to integrate.

Returns:

the integration of dx/dt = f(x) for dt.

rk4

public static double rk4(BiFunction<Double,Double,Double> f, double x, Double u, double dtSeconds)

Performs Runge Kutta integration (4th order).

Parameters:

f - The function to integrate. It must take two arguments x and u.

x - The initial value of x.

u - The value u held constant over the integration period.

dtSeconds - The time over which to integrate.

Returns:

The result of Runge Kutta integration (4th order).

rk4

public static <States extends Num, Inputs extends Num> Matrix<States,N1> rk4(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds)

Performs 4th order Runge-Kutta integration of dx/dt = f(x, u) for dt.

Type Parameters:

States - A Num representing the states of the system to integrate.

Inputs - A Num representing the inputs of the system to integrate.

Parameters:

f - The function to integrate. It must take two arguments x and u.

x - The initial value of x.

u - The value u held constant over the integration period.

dtSeconds - The time over which to integrate.

Returns:

the integration of dx/dt = f(x, u) for dt.

rk4

public static <States extends Num> Matrix<States,N1> rk4(Function<Matrix<States,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, double dtSeconds)

Performs 4th order Runge-Kutta integration of dx/dt = f(x) for dt.

Type Parameters:

States - A Num prepresenting the states of the system.

Parameters:

f - The function to integrate. It must take one argument x.

x - The initial value of x.

dtSeconds - The time over which to integrate.

Returns:

4th order Runge-Kutta integration of dx/dt = f(x) for dt.

rkdp

public static <States extends Num, Inputs extends Num> Matrix<States,N1> rkdp(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds)

Performs adaptive Dormand-Prince integration of dx/dt = f(x, u) for dt. By default, the max error is 1e-6.

Type Parameters:

States - A Num representing the states of the system to integrate.

Inputs - A Num representing the inputs of the system to integrate.

Parameters:

f - The function to integrate. It must take two arguments x and u.

x - The initial value of x.

u - The value u held constant over the integration period.

dtSeconds - The time over which to integrate.

Returns:

the integration of dx/dt = f(x, u) for dt.

rkdp

public static <States extends Num, Inputs extends Num> Matrix<States,N1> rkdp(BiFunction<Matrix<States,N1>,Matrix<Inputs,N1>,Matrix<States,N1>> f, Matrix<States,N1> x, Matrix<Inputs,N1> u, double dtSeconds, double maxError)

Performs adaptive Dormand-Prince integration of dx/dt = f(x, u) for dt.

Type Parameters:

States - A Num representing the states of the system to integrate.

Inputs - A Num representing the inputs of the system to integrate.

Parameters:

f - The function to integrate. It must take two arguments x and u.

x - The initial value of x.

u - The value u held constant over the integration period.

dtSeconds - The time over which to integrate.

maxError - The maximum acceptable truncation error. Usually a small number like 1e-6.

Returns:

the integration of dx/dt = f(x, u) for dt.