itaps-parallel Questions about iMeshP

[Tim Tautges]

Correct.

- tim

Mark Beall wrote:
> For the known examples of needing multiple partitionings is there 
> generally any correlation between the partitions (meaning that entities 
> in one partitioning end up on the same processors as entities in the 
> other partitioning)? I assuming there is a very low correlation between 
> the partitionings, almost by definition (since, otherwise, why have the 
> other partitioning). Is that correct?
> 
> mark
> 
> On Dec 21, 2009, at 11:56 AM, Tim Tautges wrote:
> 
>> Interesting.  I've thought about PIC codes in the context, but always 
>> wondered whether apps would consider it overkill to do the particles 
>> with vertices (which I think is what you're implying below?  Or not?)
>>
>> - tim
>>
>> Devine, Karen D wrote:
>>> Thanks, Tim, for providing a good example.  Here's another:  a
>>> particle-in-cell code can partition the mesh one way for force 
>>> calculations
>>> and a different way for particle calculations.  The force 
>>> calculations use a
>>> static partitioning; the particle calculations use a dynamic 
>>> partitioning
>>> that attempts to maintain particle balance.
>>> Karen
>>> On 12/18/09 9:54 AM, "Tim Tautges" <tautges at mcs.anl.gov> wrote:
>>>> The best example, brought up by both Karen and me IIRC, is of
>>>> large-deformation transient dynamics with contact, where
>>>> the FE solution of the dynamics is solved on 3d elements on one 
>>>> partition, and
>>>> the contact solution is solved on faces
>>>> on a different partition.  Many believe it was this capability that 
>>>> made truly
>>>> scalable parallel FEM with contact even
>>>> possible.  See e.g.
>>>>
>>>> Transient dynamics simulations: parallel algorithms for contact 
>>>> detection and
>>>> smoothed particle hydrodynamics,
>>>> Proceedings of the 1996 ACM/IEEE conference on Supercomputing, 1996.
>>>>
>>>> That's just one reference, there are many others for that particular 
>>>> work.
>>>>
>>>> I think the details of multiple *active* partitions still need some 
>>>> work, both
>>>> in use cases and in how they behave under
>>>> iMeshP.  Normally I wouldn't advocate such an unexplored thing being 
>>>> part of
>>>> the initial interface definition, but in
>>>> this case I think it's an important enough capability that it's 
>>>> justified.
>>>>
>>>> - tim
>>>>
>>>> Mark Beall wrote:
>>>>> As a more general context to the questions that Saurabh asked, the 
>>>>> main
>>>>> questions we have about iMeshP are issues related to having multiple
>>>>> partitions. Although we won't be supporting that for now (since our
>>>>> software doesn't support that), it would be helpful in understanding
>>>>> that need if someone could give some examples of how this 
>>>>> functionality
>>>>> would be used.
>>>>>
>>>>> mark
>>>>>
>>>>>
>>>> -- 
>>>> ================================================================
>>>> "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
>>>>
>>>>
>>>>
>>
>> -- 
>> ================================================================
>> "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
>>
> 
> 

-- 
================================================================
"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