[R] Euler & Runge-Kutta

[Franklin Bretschneider]

Hello Tom Mosca,

Re:

> Can someone help me with R code to perform approximations to second order differential equations and systems of first order differential equations using Euler's method and Runge-Kutta?  I am not a student and this is not for a test or graded assignment.
> 
> Examples (unrelated to each other):
> 
> h = 0.1
> 
> 1.  3(t^2)y'' - 5ty' + 5y = 0
>     y(1) = 0, y'(1) = 2/3
> 
> 2.  Lotka-Volterra
>     x' = x(3-y)
>     y' = y(x-3)
> 


For solving differential equations, the famous "lsoda" solver is best, far better than the simple Euler method, and also better than Runge & Kutta.
Angels, or very nice people, implemented solving methods using the lsoda into R. Download the package "deSolve" and the world of numerical solutions is at your feet.

Succes, Franklin
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Franklin Bretschneider
Dept of Biology
Utrecht University
bretschr at xs4all.nl