Subject: Re: Task identifiers

From: L J Clarke <[email-masked]>
Date: Thu, 4 Mar 93 12:16:27 GMT

> I think that we agreed to defer dynamic issues to a future MPI standard
> level, but I do agree that this is never guaranteed to happen, as Rusty
> has said.  
 
Unless of course we all want to and can afford from our funding more
beano trips to Dallas ;-) (joking, honest guv!)
 
> The lack of control for processes, and the lack of dynamic
> group syntax/semantics worries me.  They will almost certainly appear as
> non-portable extensions.
 
Yup, probably, over what timescale do we think? 
 
> Perhaps the original N-month limit was too short to permit the best
> possible standard.
> 
 
Perhaps, but on the other hand dynamic groups (i.e., those where the
membership changes in time during the existence of the group, if I
understand the emergent MPI jargon correctly (hey, we need a glossary of
MPI terminology, any volunteers?)) really do seem to be at an
experimental stage in our worlds.  

We have dynamic groups in the system we have implemented (CHIMP), but to
be quite honest hardly any users have really used them to implement
dynamic groups, rather they have implemented static groups (i.e., those
where the membership does not change in time during the existence of the
group, if I understand the emergent MPI jargon correctly (hey, we need a
glossary of MPI terminology, any volunteers?)).

Dynamic groups have been put into PVM3, as experimental functions which
may or may not survive in the current or some other form. 
 
In short, it seems to be just too early to try to define a standard for
dynamic groups (glossary), which is of course unfortunate.  I'd suggest
strongly that we must have an open mind toward - or even plan for - a
later invocation of MPI, at which point subjects such as dynamic group
and dynamic process models are dealt with. 

Best Wishes
Lyndon

         /--------------------------------------------------------\
    e||) | Lyndon J Clarke    Edinburgh Parallel Computing Centre | e||) 
    c||c | Tel: 031 650 5021  Email: [email-masked]  | c||c 
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