itaps-parallel Issues with prefix_sendEntArrToPartsPar and prefix_recvEntArrToPartsPar

[Onkar Sahni]

Part of the reason is the need for an entity to know handle/pointers of
its image on other parts (this involves entities which are non-objects and
have images on multiple parts like mesh faces on inter-part boundaries,
and also mesh edges and vertices, for a 3D case with mesh regions as
objects).

Other reason one can think of (for communications) is to determine
residence parts for non-object entities (after migration), i.e., on which
parts any non-object would exist, assuming destination part for each
object is provided.

- Onkar

> Why is a single pair not sufficient?  Does it have to do with needing to
> know the handle on the destination proc?
>
> - tim
>
> Onkar Sahni wrote:
>> The document Ting sent few days ago provides details of mesh migration
>> code, specifically how it is done in FMDB. With this document I would
>> like
>> to mention one important point.
>>
>> It is critical to realize that one set/pair of send and recv. is not
>> sufficient to keep mesh-database up to date as mesh migration is done
>> (whether for partitioning and/or for local mesh modifications).
>> Basically
>> to keep track of remote copies (independent of issue whether owner knows
>> all remote-copies or all remote-copies know all other remote-copies),
>> one
>> set/pair of send and recv. is not sufficient. Hence,
>> prefix_sendEntArrToPartsPar and prefix_recvEntArrToPartsPar will not be
>> sufficient.
>>
>> So we will have to re-visit these functions (as I remember the
>> impression
>> was that these would be enough for mesh migration for mesh-partitioning
>> and NOT mesh-modifications, where Carl and I are trying to resolve
>> issues
>> with the latter (mesh-modification) one).
>>
>> Please let me know if you have questions.
>>
>> - Onkar
>>
>>
>>> Dear All,
>>>
>>> The attached is the pseudo code of current FMDB migration algorithm and
>>> some simple explanations. Please let me know if you have any problems.
>>> Thanks.
>>>
>>> Regards,
>>>
>>> Ting
>>>
>>>
>>>
>>
>>
>>
>
> --
> ================================================================
> "You will keep in perfect peace him whose mind is
>    steadfast, because he trusts in you."               Isaiah 26:3
>
>               Tim Tautges            Argonne National Laboratory
>           (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
>           phone: (608) 263-8485      1500 Engineering Dr.
>             fax: (608) 263-4499      Madison, WI 53706
>
>