[mpich-discuss] Error: "MPIR_Get_contextid_sparse_group(1193): Too many communicators (0/2048)"

[Ted Sariyski]

Memory limitations. With one large window all processes have to allocate 
memory for the objects they own as well as for objects assigned to other 
process. May be I need to assign all objects to one process with large 
memory. After the assembly is done, data will be scattered back for 
processing. Do you have other suggestions?
Thanks,
--Ted





On 05/21/2014 05:42 PM, Balaji, Pavan wrote:
> Creating so many communicators is not a good idea.  Why can’t all processes open one large window?
>
>    — Pavan
>
> On May 21, 2014, at 4:10 PM, Ted Sariyski <tsariysk at craft-tech.com> wrote:
>
>> Hi,
>>
>> I am working on a long-range interaction problem, so that communication is "each-to-each", although very sparse. My current approach is as follow:
>>      1. If a process owns an object A,  it opens a shared window to this object.
>>      2. If another process happens to generate data which belongs to A, which is determined on the fly, it 'put' its share to A.
>>
>> The algorithm works for small number of objects, but I need millions of them. I wonder:
>>       1. Is it possible to increase the number of communicators above 2048?
>>       2. Is it a scalable  approach?
>>
>> Again, although that communication is 'each-to-each', it is extremely sparse. Any advise and comments are highly appreciated.
>>
>> Thanks in advance,
>> --Ted
>>
>>
>>
>>
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-- 
Ted Sariyski
Senior Research Scientist
Combustion Research & Flow Technology, Inc. (CRAFT Tech)
6210 Keller's Church Road, Pipersville, PA 18947-1020
Voice: (215) 766-1520 x14; Fax: (215) 766-1524
http://www.craft-tech.com