[petsc-users] DMShellSetCreateRestriction

[anton]

On 03/11/2016 11:25 PM, Barry Smith wrote:
>    Boris,
>
>      We will add this support to the DMShell and its usage from PCMG within a few days.
>
>     Barry
>

Tanks Barry. This is super-fast and very helpful.


Cheers,
Anton
>> On Mar 11, 2016, at 3:39 PM, Boris Kaus <kaus at uni-mainz.de> wrote:
>>
>>
>>> On Mar 11, 2016, at 8:53 PM, Matthew Knepley <knepley at gmail.com> wrote:
>>>
>>> On Fri, Mar 11, 2016 at 12:26 PM, Dave May <dave.mayhem23 at gmail.com> wrote:
>>> On 11 March 2016 at 18:11, anton <popov at uni-mainz.de> wrote:
>>> Hi team,
>>>
>>> I'm implementing staggered grid in a PETSc-canonical way, trying to build a custom DM object, attach it to SNES, that should later transfered it further to KSP and PC.
>>>
>>> Yet, the Galerking coarsening for staggered grid is non-symmetric. The question is how possible is it that DMShellSetCreateRestriction can be implemented and included in 3.7 release?
>>>
>>> It's a little more work than just adding a new method within the DM and a new APIs for DMCreateRestriction() and DMShellSetCreateRestriction().
>>> PCMG needs to be modified to call DMCreateRestriction().
>>>
>>> Dave is correct. Currently, PCMG only calls DMCreateInterpolation(). We would need to add a DMCreateRestriction() call.
>> The PCMG object already uses a restriction operator that is different from the interpolation parameter if it is specified with PCMGSetRestriction.
>> For consistency, one would expect a similar DMCreateRestriction object, not? I realize that this is not relevant for FEM codes, but for staggered FD it makes quite some difference.
>>
>> Other suggestions on how to best integrate staggered finite differences within the current PETSc framework are ofcourse also highly welcome.
>> Our current thinking was to pack it into a DMSHELL (which has the problem of not having a restriction interface).
>>
>> thanks,
>> Boris
>>
>>
>>
>>
>>>    Thanks,
>>>
>>>      Matt
>>>   
>>> Please, please.
>>>
>>> Thanks,
>>> Anton
>>>
>>>
>>> -- 
>>> 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