Iterative solver (again) [Was: Re: [ODE] Russ' plans forODE?]

[Alen Ladavac]

> you may me interested in:
>
> http://www.shaderx2.com/shaderx.PDF
>
> where a projected Jacobi method is mentioned.

Yes, I'm talking about something similar to that. Though if you are not
running massively parallel (as GPU has to), you can just use Gauss-Seidel.
But those are all just fancy-words. It is same as Jacobi, just meaning that
you immediatelly use available results.

> http://vcg.isti.cnr.it/people/vcgpeople/mendoza/jnrr.pdf
>
> if you look carefully the first jacobi iteration started with force=0 is
the same as step fast where off diagonal elements disappear. so it looks
> like that step fast is like running the first iteration, setting the force
to zero and running the first iteration again.

I believe that Mendoza uses biconjugate gradient method, but other than
that, yes, it is very similar. And it's exactly what my recent objection to
stepfast was - it does only the first iteration.

Alen