Re: Acausal systems modelling and compilation

[Arquimedes Canedo]

Francesco,


Thanks for the insightful answers.


> The solution of an initial value problem for a higher index DAE and for the
> same DAE brought to index 1 with Pantelides / Dummy Derivatives is exactly
> the same.

This is good news. The only place where we could have numerical error
is then the numerical solver itself.

> If the implicit algebraic equations have a unique solution in closed form, a
> symbolic manipulator could solve them symbolically and replace them with
> their closed-form solution. Otherwise, you typically use numerical,
> Newton-like solvers, which require to know the residuals of the implicit
> equations, and possibly their Jacobian w.r.t. the unknowns.

This sounds familiar, at least that is what Scicos/Simulink try to
handle the algebraic loops.
I guess this is all explained in detail in the books you have
recommended before. I'll try to get my hands on them soon.


Thanks,

Arquimedes