[ODE] How to do iterative

[Martin C. Martin]

> A*lamda = b (plus some stuff for the LCP solver to simulate friction and
> limits..)

Once you've got a lambda, why not do this:

next_lambda = prev_lambda + delta_lambda

A * next_lambda = A * (prev_lambda + delta_lambda) = b

therefore,

A * delta_lambda = b - A * prev_lambda

So you can solve for delta_lambda directly if you make your rhs   b - A *
prev_lambda

This is why I asked whether you'd gotten all the physics out of the loop
and were left only with linear algebra...

- Martin