[MOAB-dev] question about reduce_tags behavior

[Lorenzo Alessio Botti]

Dear Tim,
thanks a lot. It works very well now.
However, plugging it in SpaFEDTe I noticed that, clearly, I have to call resolve_shared_ents before deleting and recreating the GLOBAL_ID tag.
So I'm wondering if I have the possibility to create (in parallel) a field of global ids at the vertices in order to call resolve_shared_ents only afterwards.
I've tried with assign_global_ids but had no success.
This would also be required when reading a mesh without vertex ids so I guess that there is a way to do it.

Thanks again, MOAB is great!
Lorenzo 



On May 10, 2012, at 7:36 PM, Tim Tautges wrote:

> 
> 
> On 05/04/2012 11:27 AM, Lorenzo Alessio Botti wrote:
>> I don't know if it's a bug or if I initially misunderstood the behavior of reduce_tags
>> 
>> Know it works as follows
>> 
>> pcomm->reduce_tags(gid_tag_vec, gid_tag_vec, MPI_SUM, sharedFaces);
>> provides in gid_tag_vec the sum of the tag values on shared faces, so it sums the value of the tag on the owned and on
>> the not_owned entity. This is what I need in my code.
>> 
>> pcomm->reduce_tags(gid_tag_vec, gid_sum_tag_vec, MPI_OP_NULL, sharedFaces);
>> provides in gid_sum_tag_vec the values of gid_tag_vec on the owned ents, so this call replicates the behavior of
>> exchange_tags
>> 
>> pcomm->reduce_tags(gid_tag_vec, gid_sum_tag_vec, MPI_SUM, sharedFaces);
>> provides in gid_sum_tag_vec the sum of the gid_tag on the owned entity and the gid_sum_tag on the actual process
>> (independently of the pstatus)
>> 
> 
> This should be fixed now, in R5514.  In an unusual burst of discipline, I also added a test case for it (made debugging easier, besides just being A Good Idea).  Lemme know if it doesn't appear fixed for you, and thanks for the bug report.
> 
> - tim
> 
>> Is this the expected behavior?
>> 
>> Thanks
>> Lorenzo
>> 
>>> 
>>> On May 4, 2012, at 5:46 PM, Tautges wrote:
>>> 
>>>> If I read your message right, it's a bug with when you want the result in a different tag? Will fix this soon, should
>>>> be easy.
>>>> 
>>>> On your msg about mbzoltan, the fix is much appreciated, we'll definitely get that in the code base. Dont know yet
>>>> about the option string, haven't looked at code yet.
>>>> 
>>>> - tim
>>>> 
>>>> (Sent from an Androd that dosnt autocorect as wel as an ipone)
>>>> 
>>>> 
>>>> 
>>>> -------- Original message --------
>>>> Subject: Re: question about reduce_tags behavior
>>>> From: Lorenzo Alessio Botti <ihabiamx at yahoo.it <mailto:ihabiamx at yahoo.it>>
>>>> To: Tim Tautges <tautges at mcs.anl.gov <mailto:tautges at mcs.anl.gov>>,MOAB-dev at mcs.anl.gov <mailto:MOAB-dev at mcs.anl.gov>
>>>> CC:
>>>> 
>>>> 
>>>> Hi Tim,
>>>> I've found the bug in my code...
>>>> To get the sum of a tag on shared entities I need to call
>>>> 
>>>> pcomm->reduce_tags(gid_tag_vec, gid_tag_vec, MPI_SUM, sharedFaces);
>>>> and not
>>>> pcomm->reduce_tags(gid_tag_vec, gid_sum_tag_vec, MPI_SUM, sharedFaces);
>>>> 
>>>> Here is the new version, now it works...
>>>> 
>>> 
>> 
> 
> -- 
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> 
>             Tim Tautges            Argonne National Laboratory
>         (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
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