[ODE] Iterative solution

[Adam D. Moss]

Adam D. Moss wrote:
>> My next task is to optimize the dInternalStep routine with the knowledge
>> that it will always get 1 joint and either 1 or 2 bodies.  Here's the
>> question for the math/physics gurus:  Is the LCP solver even necessary if
>> you know beforehand that there is only one joint (up to 6 constraints, 1
>> per DOF I believe) in effect? 
> 
> I'm not a math/physics guru.  I do recall that when this subject was
> discussed a month or so ago, the consensus was that the 6 DOF constraint
> solving still be done with the LCP solver, but that the LCP solver
> can be optimized to death when there are just a fixed and small number
> of constraints (6) to solve.

Wait, I remember, I do have slightly more practical experience
with this than I thought at first. :)

Since you're iterating multiple times, you can attempt to resolve
each of the DOF constraints independantly and still have the
body converge upon the correct position/orientation.  Since
a body will usually have <6 constraints it can work out to less
work.  But, from an implementation point of view there /may/ be
expensive computation that's shareable between each of the
individual DOF constraint solutions.  At the moment in my non-ODE
simulation thing I iteratively resolve the DOF constraints in
sets of two or three, though there are other non-physics
constraints mixed in there so my implementation just gets a bit
strange.

--Adam
-- 
Adam D. Moss   . ,,^^   adam@gimp.org   http://www.foxbox.org/   co:3
busting makes me feel good
kthx bye