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

[Peter Brune]

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.
>
> 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
>
>
>
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