[MOAB-dev] Parallel MOAB usage

[Vijay S. Mahadevan]

Hi Filipe,

> 1. Is there any method to access an element in a mesh partition from another partition? E.g., get the elements surrounding another element which could possibly belong to another processor. I've tried to use the  get_bridge_adjacencies method from moab::MeshTopoUtil but it does not seem to work this way.

Unless the elements that you are trying to access are ghosted
a-priori, there is no way to access entities on a different partition
directly. Remember that the strength of MOAB comes from the fact that
we maintain a fully parallel view of the mesh. We do not replicate the
mesh on every process. None of the adjacency calls will work unless
the element is available in the local partition (either as a owned or
ghosted element).

> 2. How the send_entities and recv_entities methods from ParallelComm class work? Is it similar to MPI_Send and MPI_Receive? I would like to know more about those methods's arguments.

Yes these methods in ParallelComm can help you exchange entities but
these are advanced methods and yes, we do utilize ISend/IRecv methods
underneath to exchange the buffers. The API documentation is available
here [1]. If you can explain your use case, perhaps we can suggest a
better way to approach it.

Vijay

[1] http://ftp.mcs.anl.gov/pub/fathom/moab-docs/classmoab_1_1ParallelComm.html#aa921ffb8f68a405ff88aba80f7597a2a

On Wed, Oct 17, 2018 at 3:31 PM Filipe Antonio Cumaru Silva Alves
<facsa at cin.ufpe.br> wrote:
>
> Hello,
> I am using MOAB to accomplish some tasks in parallel computing of meshes and I've got some doubts about it.
>
> 1. Is there any method to access an element in a mesh partition from another partition? E.g., get the elements surrounding another element which could possibly belong to another processor. I've tried to use the  get_bridge_adjacencies method from moab::MeshTopoUtil but it does not seem to work this way.
>
> 2. How the send_entities and recv_entities methods from ParallelComm class work? Is it similar to MPI_Send and MPI_Receive? I would like to know more about those methods's arguments.
>
> Thank you.
>
> --
> Atenciosamente,
> Filipe Antônio Cumaru Silva Alves
>
> Graduando em Engenharia da Computação (2016.1)
> Monitor de Interface Hardware-Software (IF817)
> Bolsista de iniciação científica CNPq no PADMEC (Processamento de Alto Desempenho na Mecânica Computacional)