Peter, Just wanted to make sure there wasn't some Sundials-specific option for finite difference Jacobians that I was missing; despite reading the manual, it's a large package, and it's easy to miss things. If that's the case, I'd like to make a feature request for such an option.
Geoff On Jun 21, 2012, at 9:53 AM, Peter Brune wrote: > Note that in the code in ts/impls/implicit/sundials it says: > > This uses its own nonlinear solver and krylov method so PETSc SNES and KSP > options do not apply... > > - Peter > > On Jun 21, 2012 7:59 AM, "Geoff Oxberry" <goxberry at gmail.com> wrote: > Running the following example from PETSC 3.3.0-dev (changeset: > 23631:0e86ac5e4170) > > /path/to/petsc-dev/src/ts/examples/tutorials/ex8 -problem_type rober -snes_fd > -ts_type sundials > > gives the following output > > steps 1000 (0 rejected, 0 SNES fails), ftime 744.845, nonlinits 3739, linits > 3739 > WARNING! There are options you set that were not used! > WARNING! could be spelling mistake, etc! > Option left: name:-snes_fd no value > > Just to confirm, is it currently impossible to use a finite difference > Jacobian matrix in concert with CVODE? If so, could this feature be > implemented in a future release? I currently rely on Sundials to integrate > stiff systems of ODEs, and for my application, it is impractical to derive an > analytical Jacobian matrix. (It is an issue I've discussed both with Jed and > Matt on another forum.) > > Cheers, > > Geoff -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120621/fa090df4/attachment.html>
