[MOAB-dev] Questions about best ways to get help with moab

[Grindeanu, Iulian R.]

Hi Michel,

You are right, calling in a loop does not work.
Let me think about it, and see how to properly implement it;
I have a branch that should work better when there is no crossing over another partition. (iulian07/ghost_layers_issue)

when some partitions are thin, this still does not work.
Sorry about it.

Iulian



________________________________________
From: Michel de Messieres <demessie at txcorp.com>
Sent: Tuesday, November 13, 2018 5:21:40 PM
To: Grindeanu, Iulian R.
Subject: Re: [MOAB-dev] Questions about best ways to get help with moab

hi,

If I can do this one layer at a time that should be completely fine.

I had tried this a while ago but probably did it incorrectly as I remember I got discouraged with that approach.

Can you briefly describe how this would look for making the 2 calls?

I think the first call is clear where I exchange 1 layer.

But for the second call, should I then be calling for 1 layer or 2?
Do I need to do anything special before doing that so moab processes the first layer which is shared between ranks correctly?

Many thanks,
Michel

PS - I’ll check why I had the shared ents - I built the demo from a moab test attempting to simplify from my application so perhaps did something wrong, but I think I was having an issue getting my global ids consistent across ranks for my error checking.

> On Nov 13, 2018, at 5:58 PM, Grindeanu, Iulian R. <iulian at mcs.anl.gov> wrote:
>
> Hi Michel,
> Sorry for the silence, this is the proper channel
>
> In general, ghosting with more than 1 layer has issues;
>
> I think the correct workaround is to ghost layer by layer
>
> the problem is related to partitions that are one layer "thick" ;
> if processor 1 has one layer of elements, but it is between partition 0 and 2, when you request 2 layers, you would expect that partition 2 to ghost something from partition 0 too; with the current code, it is not possible to do it in one run (in short, processor 0 does not know in advance it has to ghost to 2);
>
> I am not sure what kind of tests you do, it is hard to understand the code; why do you resolve shared ents again ? (I see another call to resolve shared ents)
>
>
> Iulian
>
>
> ________________________________________
> From: moab-dev <moab-dev-bounces at mcs.anl.gov> on behalf of Michel de Messieres via moab-dev <moab-dev at mcs.anl.gov>
> Sent: Tuesday, November 6, 2018 11:02:17 AM
> To: moab-dev at mcs.anl.gov
> Subject: [MOAB-dev] Questions about best ways to get help with moab
>
> Dear Moab team,
>
> I’m working at Tech-X Corporation and trying to resolve some issues we have with our MOAB code.
>
> I opened up issue #93 but noticed there is not much traffic on the issue site.
>
> So I wanted to check if that’s a good way to get some help or if I should be using other channels.
>
> Generally I need some assistance on proper use of the ghost exchange calls so I can determine if behavior I am seeing is related to bugs or improper usage.
>
> Many thanks for any assistance.
>
> cheers,
> Michel de Messieres
>