[Tutor] hi

[Vick]

> -----Original Message-----
> From: Oscar Benjamin [mailto:oscar.j.benjamin at gmail.com]
> Sent: Monday, 12 August, 2013 18:18
> 
> On 12 August 2013 13:08, Oscar Benjamin <oscar.j.benjamin at gmail.com>
> wrote:

> The rational approximations are intended to
> be good enough for use with double precision but are insufficient for the
30
> dps setting that you are using. The reason given by the authors for
publishing
> approximate coefficients is that (in 1981) it was deemed computationally
> intractable to compute the exact rational coefficients. However that may
not
> still be the case with modern computing power. I doubt that I'll attempt
this
> any time soon but if you're able (and bothered) to do that I'd love to
know
> what the coefficients would be.
>
[Vick] Yeah they are rational coefficients and I got them from the google
book satellites orbits which I believe I posted the links for it previously.

The problem is how are the coefficients derived? I've never seen an
algorithm to compute the coefficients of an integrator method. Anyway it
would surely involve complicated coding to start an algorithm to compute
them. If I can get it somewhere, I wouldn't mind doing the DOPRI8
computations.

Vick