[ODE] ODE announcement: new iterative solver

Antonio_Martini at scee.net Antonio_Martini at scee.net
Tue May 18 10:46:00 MST 2004





the time step is subdivided only to minimize the energy added by the
positonal error correction.
positional errors(penetrations) are fixed by altering the relative contact
velocities(dv = dp/dt) so a smaller numerical
integration time step means less energy. Step fast would work even if the
time step is not subdivided(numerical integration out of the loop), only
the error
correction would be worse. However as it has already been pointed out in
the prveiuos posts, Step Fast is in practice a iterative method
with  worst convergence speed if compared to a basic projected block
Jacobi(or Guass-Seidel or ....) iterative solver.





"Aras Pranckevicius" <nearaz at interamotion.com>@q12.org on 17/05/2004
17:55:56

Sent by:    ode-bounces at q12.org


To:    ode at q12.org
cc:
Subject:    Re: [ODE] ODE announcement: new iterative solver


> > Sounds great.  Out of interest, how does this currently
> > compare with StepFast in terms of speed/size/stability?  I
> > think that's a more interesting comparison than with stepslow,
> > since I guess the methods are a lot closer.
>
> i'm anticipating QuickStep will be faster: it's a far simpler chunk
> of code that implements an algorithm that should converge more

Theoretically, it should be better than StepFast... As Alen recently
pointed
out, StepFast isn't "iterative" method at all, it just subdivides timestep
and does serial solving of joints.

(and I always thought that StepFast doesn't just subdivide timestep, but
really does the "iterations"! :))


Aras Pranckevicius aka NeARAZ
http://www.gim.ktu.lt/nesnausk/nearaz/

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