[petsc-users] Using -ts_type sundials with -snes-fd

[Peter Brune]

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
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