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Re: Help with ODE's
- From: Brian Gough <bjg at network-theory dot co dot uk>
- To: Sam Halliday <sam at neutrino dot phy dot uct dot ac dot za>
- Cc: gsl-discuss at sources dot redhat dot com
- Date: Tue, 30 Apr 2002 19:56:05 +0100 (BST)
- Subject: Re: Help with ODE's
- References: <200204271500.g3RF03IF024713@neutrino.phy.uct.ac.za>
Sam Halliday writes:
> Hello there,
> i think gsl is a fantastic project, and i've been using it in my
> simulations since i found out about it.
> i have only ever had to solve 2 ODEs at one time, and i was lucky
> enough that the example in the documentation deals with this
> scenario, however i find the API of the ODE part of the library to
> be somewhat cryptic and i am having problems changing my code to
> solve for 3 ODEs at one time.. could anyone please give me some
> pointers as to how i would do that?
Check each function call in the program against the manual to see
where you need to change 'dimension' arguments from 2 to 3.
> and also, i noticed that to do an 8th order runge-kutta i must
> declare a jacobian, could somebody please explain to me how i get
> this from my equations? i am aware of jacobians in mathematics, but
> never heard of it in numerics, i must admit i am of an analytic
> background.
The jacobian isn't needed for Runge-Kutta, you can just use an empty
function.
regards
Brian Gough