I asked my question because it might be happening automatically. His output looked like the equation was solved. A brief google search on this makes it look like they do this anyways. In addition:
http://www.mcs.anl.gov/petsc/petsc-dev/src/ts/impls/implicit/sundials/sundials.c.html#TSView_Sundials directly refers to "Sundials no. of rhs calls for finite diff. Jacobian-vector evals." - Peter On Thu, Jun 21, 2012 at 9:48 AM, Matthew Knepley <knepley at gmail.com> wrote: > On Thu, Jun 21, 2012 at 8:45 AM, Peter Brune <prbrune at gmail.com> wrote: > >> What do you see when you run with -ts_view? >> >> - Peter >> >> >> On Thu, Jun 21, 2012 at 9:40 AM, Geoff Oxberry <goxberry at gmail.com>wrote: >> >>> 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. >>> >> > If I understand correctly, you want a MF Jacobian with Sundials. We can't > do that because Sundials is completely > closed package, which we cannot pry apart to insert something like this. > The alternative is to use the stuff solvers > we currently have in TS. I thought that you had used the Rosenbrock-W > stuff. Is this sufficient? > > Thanks, > > Matt > > >> 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 >>> >>> >>> >> > > > -- > What most experimenters take for granted before they begin their > experiments is infinitely more interesting than any results to which their > experiments lead. > -- Norbert Wiener > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120621/627e5c15/attachment.html>
