[MOAB-dev] GLOBAL_IDs, building map from moab mesh

[Grindeanu, Iulian R.]

yes, that would be one easy way (we assume though that build is parallel) 
maybe we should move the method to Core or some other utility

for serial it is actually easy, we can just assign ids in order, during mbconvert (few lines of code, does it really need a method?)
________________________________________
From: moab-dev-bounces at mcs.anl.gov [moab-dev-bounces at mcs.anl.gov] on behalf of Vijay S. Mahadevan [vijay.m at gmail.com]
Sent: Monday, December 07, 2015 5:21 PM
To: Nico Schlömer
Cc: moab-dev at mcs.anl.gov
Subject: Re: [MOAB-dev] GLOBAL_IDs, building map from moab mesh

The vtk file does not have a GLOBAL_ID point data defined. So MOAB
defaults this to 0 I think for all vertices when you do the
conversion. This isn't quite a bug but just that your input file is
not what MOAB expects, in a sense.

Iulian, can we add an option in mbconvert to assign global ID's ?
Should be a simple call to pcomm->assign_global_ids for all entities,
if the user wants it.

Vijay

On Mon, Dec 7, 2015 at 6:11 PM, Nico Schlömer <nico.schloemer at gmail.com> wrote:
> Nope, not playing around with anything. Simply run
> ```
> mbconvert pacman.vtk pacman.h5m
> ```
> on [1] and find the GLOBAL_IDs all zeroed out. Can you confirm? If yes, I'll
> be happy to file a bug.
>
> Cheers,
> Nico
>
> [1] http://chunk.io/f/ea2a0f63adf04a2bb57338fe853ab05b
>
> On Mon, Dec 7, 2015 at 10:29 PM Vijay S. Mahadevan <vijay.m at gmail.com>
> wrote:
>>
>> Using GLOBAL_ID for finding matching entities is the simplest way to
>> address your use case.
>>
>> > I now bumped into a bug in serial execution. I noticed that the output
>> > of
>> > `mbconvert somefile.vtk somefile.h5m` generates GLOBAL_ID list full of
>> > 0s,
>> > as opposed to the nice list of 1, 2, 3,... as generated by `mbpart`.
>> > Apparently you're not supposed to rely on GLOBAL_ID after all? Is there
>> > a
>> > better approach that also works in serial?
>>
>> This seems fishy. Are you overwriting the GLOBAL_ID or setting it
>> yourselves in memory ?
>>
>> Vijay
>>
>> On Mon, Dec 7, 2015 at 4:13 PM, Nico Schlömer <nico.schloemer at gmail.com>
>> wrote:
>> > Hi everyone,
>> >
>> > To build a map for multi-process meshes, I need to be able to identify
>> > that
>> > node N on proc 0 is the same as node M on proc 1. For this, I'm using
>> > the
>> > GLOBAL_ID property. I know that this list isn't necessarily contiguous
>> > or
>> > 1-based, but that's fine.
>> >
>> > I now bumped into a bug in serial execution. I noticed that the output
>> > of
>> > `mbconvert somefile.vtk somefile.h5m` generates GLOBAL_ID list full of
>> > 0s,
>> > as opposed to the nice list of 1, 2, 3,... as generated by `mbpart`.
>> > Apparently you're not supposed to rely on GLOBAL_ID after all? Is there
>> > a
>> > better approach that also works in serial?
>> >
>> > Cheers,
>> > Nico