R: Runge-Kutta Method for Solving Differential Equations

runge.kutta {rmutil} | R Documentation

## Runge-Kutta Method for Solving Differential Equations

### Description

`runge.kutta` numerically solves a differential equation by the fourth-order Runge-Kutta method.

### Usage

    runge.kutta(f, initial, x)

### Arguments

`f` | A function `dy/dx=func(y,x)`.
`initial` | The initial value of `y`.
`x` | A vector of values of `x` for which the values or `y` are required.

### Value

A vector of values of `y` as solution of the function `f` corresponding to the values in `x`.

### Author(s)

J.K. Lindsey

### Examples

    fn <- function(y,x) (x*y-y^2)/x^2
    soln <- runge.kutta(fn,2,seq(1,3,by=1/128))
    ## exact solution
    exact <- seq(1,3,by=1/128)/(0.5+log(seq(1,3,by=1/128)))
    rbind(soln, exact)

[Package rmutil version 1.1.3 Index]