> Do you want equality or inequality constraints? Equality constraints are > naturally handled by writing a DAE.
I am looking at equality constraints only for now. But I just realized that, the constraints in VI seem only to be on variables but not on a function of it. So I guess the decoupled ODE+constraint might not have worked. On Sun, Jul 31, 2011 at 11:14 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote: > On Sun, Jul 31, 2011 at 22:11, Vijay S. Mahadevan <vijay.m at gmail.com> > wrote: >> >> I saw from the documentation that the GL methods were capable of >> handling DAE systems. But the intention of my question was about the >> usage of the newton solver with functional constraints (with VI) for a >> DAE since in a sense, the DAE systems are a composite of an ODE and a >> constraint. So I was curious whether we could use temporal methods >> that were not intended for DAEs but for stiff ODEs only and use the VI >> solver to augment/restrict the solution with constraints. The reason >> for this is due to the fact that in the creation of a stiff solver, >> there are additional coefficient constraints that need to be satisfied >> to be used for a DAE but this is less restrictive for solving ODEs. > > Do you want equality or inequality constraints? Equality constraints are > naturally handled by writing a DAE. Inequality constraints would be handled > by VI. VI is not currently available through TS, but my understanding is > that Shri is looking into this and it will eventually be available there > too.
