[petsc-users] IS natural numbering to global numbering

[YuSh Lo]

I am getting a null PetscSF after calling DMPlexGetGlobalToNatural

YuSh Lo <ysjosh.lo at gmail.com> 於 2023年6月18日 週日 上午12:18寫道：

> Hi Matthew,
>
> After setting DMSetUseNatural to true and calling DMPlexGetGlobalToNatural,
> I call PestcSFView right away, it gives segmentation fault.
> I have also tried DMGetNaturalSF, it also gives segmentation fault when
> calling PetscSFView.
> I use PETSC_VIEWER_STDOUT_WORLD as PetscViewer
>
> Thanks,
> Josh
>
>
> Matthew Knepley <knepley at gmail.com> 於 2023年6月9日 週五 下午1:04寫道：
>
>> On Fri, Jun 9, 2023 at 1:46 PM YuSh Lo <ysjosh.lo at gmail.com> wrote:
>>
>>> Hi Barry,
>>>
>>> Is there any way to use the mapping generated by DMPlexDistribute along
>>> with AO?
>>>
>>
>> For Plex, if you turn on
>>
>>   https://petsc.org/main/manualpages/DM/DMSetUseNatural/
>>
>> before DMPlexDistribute(), it will compute and store a GlobalToNatural
>> map. This can be
>> used to map vectors back and forth, but you can extract the SF
>>
>>   DMPlexGetGlobalToNaturalSF
>> <https://petsc.org/main/manualpages/DMPlex/DMPlexGetGlobalToNaturalSF/>
>>
>> and use that to remap your IS, by extracting the indices.
>>
>>   THanks,
>>
>>      Matt
>>
>>
>>> Thanks,
>>> Josh
>>>
>>>
>>> Barry Smith <bsmith at petsc.dev> 於 2023年6月9日 週五 上午10:42寫道：
>>>
>>>>
>>>>   You might be looking for
>>>> https://petsc.org/release/manualpages/AO/AO/#ao
>>>>
>>>>
>>>> On Jun 9, 2023, at 11:02 AM, Mark Adams <mfadams at lbl.gov> wrote:
>>>>
>>>> An IS is just an array of integers. We need your context.
>>>> Is this question for sparse matrices? If so look at the documentation
>>>> on the AIJ matrix construction and the global vertex numbering system.
>>>>
>>>> Mark
>>>>
>>>> On Thu, Jun 8, 2023 at 1:15 PM YuSh Lo <ysjosh.lo at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I have an IS that contains some vertex that is in natural numbering.
>>>>> How do I map them to global numbering without being distributed?
>>>>>
>>>>> Thanks,
>>>>> Josh
>>>>>
>>>>
>>>>
>>
>> --
>> 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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