[petsc-users] Change SNES/TS setting from inside context

[behzad baghapour]

Actually I want to update the domain according to the global CFL number;
e.g. dt = CFL * dx / Lambda; separately for each cell
( dx is the dimension of the cell and Lambda is the local maximum eigenvalue
of the field )

So, here shift is the maximum time step and I should adjust other cells to
this maximum value?

Thanks,




On Thu, Oct 27, 2011 at 5:49 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> On Thu, Oct 27, 2011 at 06:44, behzad baghapour <
> behzad.baghapour at gmail.com> wrote:
>
>> 2- page 120 of PETSc manual (TS): "For location-dependent
>> pseudo-timestepping, the interface function has not yet been created."
>> Is there any way to control time-step locally? (This is due to variable
>> time updating usually needed in PDE solution)
>>
>
> The documentation needs to be updated. Use TSSetIJacobian() and regard the
> "shift" as a maximum shift (corresponds to minimum time step). If you have a
> cell in which you want to take a 10x longer time step, then use shift/10 in
> that cell. Note that you can use steady-state constraints on some fields.
> For example, src/ts/examples/tutorials/ex26.c (in petsc-dev) uses no shift
> for the velocity components (enforces incompressibility in
> velocity-vorticity form).
>



-- 
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Behzad Baghapour
Ph.D. Candidate, Mechecanical Engineering
University of Tehran, Tehran, Iran
https://sites.google.com/site/behzadbaghapour
Fax: 0098-21-88020741
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