[ODE] Iterative solution

[david@csworkbench.com]

My hope was that when I got down to the level of one constraint per
problem, the 1x1 system matrix would become a simple algebraic equation,
totally getting rid of the LCP solver.  Of course, I would probably get
the same benefit from optimizing the LCP solver for the single joint case.
 So I see where you are coming from.

>
>>I'm going to look into solving one constraint at a time (as opposed to
>> one joint at a time). If it works, I think the LCP solver becomes
>> solving a single variable equation, but I could be wrong...
> i think that probably might not make it much better.
> There is an ideal(problem depedent) matrix size where the O(n^3)
> is not significant anymore and splitting the matrix further would just
> increase the number of iterations making the general solution slower.
> Maximum performances
> may not be in the 'maximum splitting' strategy of the LCP matrix but
> rather in
> a balance between relaxation an sub matrices size. Solving constraints
> directly decreases
> the number of iterations needed and as long as the matrix is small the
> O(n^3)
> complexity doesn't matter that much.
>
> Antonio
>
>
>
>
>
>
> <david@csworkbench.com>@q12.org on 17/03/2003 09:46:21
>
> Sent by:    ode-admin@q12.org
>
>
> To:    <ode@q12.org>
> cc:
> Subject:    Re: [ODE] Iterative solution
>
>
>
> I'm going to look into solving one constraint at a time (as opposed to
> one joint at a time). If it works, I think the LCP solver becomes
> solving a single variable equation, but I could be wrong.....  If you
> know for sure, let me know.  I'm spending over 80% of my time making the
> (up to) 6x6 system matrix and solving it, so anything that can be done
> to speed those steps up would help.  I'd like to go back to the Cholesky
> solver, but it ceased to work ("A is not positive definite"????) when I
> took the Jacobian calculations out of the iteration loop.  It would
> really help to figure out why that is happening.
>
> David Whittaker
>
>> Have you tried the iterative method on something like box-stacking?
>> How does it compare to the regular solver on that?
>>
>> cheers,
>> m
>>
>> _______________________________________________
>> ODE mailing list
>> ODE@q12.org
>> http://q12.org/mailman/listinfo/ode
>
>
>
> _______________________________________________
> ODE mailing list
> ODE@q12.org
> http://q12.org/mailman/listinfo/ode
>
>
>
>
>
>
>
>
>
>
> **********************************************************************
> This email and any files transmitted with it are confidential and
> intended solely for the use of the individual or entity to whom they are
> addressed. If you have received this email in error please notify
> postmaster@scee.net
>
> This footnote also confirms that this email message has been checked for
> all known viruses.
>
> **********************************************************************
>  SCEE 2002
>
> _______________________________________________
> ODE mailing list
> ODE@q12.org
> http://q12.org/mailman/listinfo/ode