[petsc-users] Modification to ex11.c

[Matthew Knepley]

On Fri, Apr 17, 2020 at 12:52 PM Mark Adams <mfadams at lbl.gov> wrote:

> Just to be clear, you seem to be suggesting adding an interface for this
> and/or code to clone?
>

Adding an interface.

  Thanks,

    Matt


> On Fri, Apr 17, 2020 at 11:08 AM Matthew Knepley <knepley at gmail.com>
> wrote:
>
>> On Fri, Apr 17, 2020 at 10:58 AM Mark Adams <mfadams at lbl.gov> wrote:
>>
>>> Line 1528 of dmplexsnes.c ?
>>>
>>
>> Yes. This is where we add in u_t, so it would make sense to also add in
>> the source term here. If it were a function of t, s(t), you would
>> just add vol*s(t).
>>
>>   Thanks,
>>
>>     Matt
>>
>>
>>> On Fri, Apr 17, 2020 at 10:41 AM Matthew Knepley <knepley at gmail.com>
>>> wrote:
>>>
>>>> Tried it again and works for me.
>>>>
>>>>    Matt
>>>>
>>>> On Fri, Apr 17, 2020 at 10:39 AM Mark Adams <mfadams at lbl.gov> wrote:
>>>>
>>>>> Matt, that kink seems messed up.
>>>>>
>>>>> On Fri, Apr 17, 2020 at 9:18 AM Matthew Knepley <knepley at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Mark is right, you could just add in a source term for each cell this
>>>>>> way.
>>>>>>
>>>>>> If you really wanted a lower level interface, it would go here I
>>>>>> think:
>>>>>>
>>>>>>
>>>>>> https://gitlab.com/petsc/petsc/-/blob/master/src/snes/utils/dmplexsnes.c#L1528
>>>>>>
>>>>>> What would you want the interface to look like?
>>>>>>
>>>>>>   Thanks,
>>>>>>
>>>>>>     Matt
>>>>>>
>>>>>> On Fri, Apr 17, 2020 at 7:55 AM Mark Adams <mfadams at lbl.gov> wrote:
>>>>>>
>>>>>>> You can write your own DMPlexTSComputeRHSFunctionFVM method like
>>>>>>> this and give that to the dm.
>>>>>>>
>>>>>>> PetscErrorCode foo(DM dm, PetscReal time, Vec locX, Vec F, void *user)
>>>>>>> {
>>>>>>>   PetscErrorCode ierr;
>>>>>>>   PetscFunctionBegin;
>>>>>>>   ierr = DMPlexTSComputeRHSFunctionFVM(dm, time, locX, F, user);CHKERRQ(ierr);
>>>>>>> ...
>>>>>>>
>>>>>>>   PetscFunctionReturn(0);
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Apr 17, 2020 at 5:28 AM MUKKUND SUNJII <
>>>>>>> mukkundsunjii at gmail.com> wrote:
>>>>>>>
>>>>>>>> Greetings,
>>>>>>>>
>>>>>>>> I had been working on ts/tutorials/ex11.c as part of my master’s
>>>>>>>> thesis.
>>>>>>>>
>>>>>>>> In ex11.c, there is a 2D Shallow Water Model. I want to modify the
>>>>>>>> model by adding a source term to the model. This source term would factor
>>>>>>>> in the effects of bathymetry or bed elevation in addition to water height.
>>>>>>>>
>>>>>>>> I know how I will be able to achieve this if just use
>>>>>>>> TSSetRHSFunction(). However ex11.c makes use of the Riemann Solver for the
>>>>>>>> computation fluxes at the interfaces (therefore, it uses
>>>>>>>> DMTSSetRHSFunctionLocal(dm, DMPlexTSComputeRHSFunctionFVM, user)
>>>>>>>> ).
>>>>>>>>
>>>>>>>> Is there a routine that allows me to *add* a source term *for
>>>>>>>> every cell* to the RHS function?
>>>>>>>>
>>>>>>>> Thank you in advance!
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>>
>>>>>>>> Mukkund
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> --
>>>>>> 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
>>>>>>
>>>>>> https://www.cse.buffalo.edu/~knepley/
>>>>>> <http://www.cse.buffalo.edu/~knepley/>
>>>>>>
>>>>>
>>>>
>>>> --
>>>> 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
>>>>
>>>> https://www.cse.buffalo.edu/~knepley/
>>>> <http://www.cse.buffalo.edu/~knepley/>
>>>>
>>>
>>
>> --
>> 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
>>
>> https://www.cse.buffalo.edu/~knepley/
>> <http://www.cse.buffalo.edu/~knepley/>
>>
>

-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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